diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/clickhouse/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/clickhouse/1.1.sql
index 6effd3ba3..0ac710ba4 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/clickhouse/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/clickhouse/1.1.sql
@@ -24,6 +24,11 @@ create table drop_ref_one (
   parent_id                     UInt32
 ) ENGINE = Log();
 
+create table drop_ref_one_to_one (
+  id                            UInt32,
+  parent_id                     UInt32
+) ENGINE = Log();
+
 create table migtest_e_test_binary (
   id                            UInt32,
   test_byte16                   String,
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/clickhouse/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/clickhouse/1.4__dropsFor_1.3.sql
index d66b81f56..54c4cfbfb 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/clickhouse/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/clickhouse/1.4__dropsFor_1.3.sql
@@ -21,6 +21,7 @@ drop table if exists drop_main;
 drop table if exists drop_main_drop_ref_many;
 drop table if exists drop_ref_many;
 drop table if exists drop_ref_one;
+drop table if exists drop_ref_one_to_one;
 drop table if exists migtest_e_test_binary;
 drop table if exists migtest_e_test_json;
 drop table if exists migtest_e_test_lob;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/clickhouse/idx_clickhouse.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/clickhouse/idx_clickhouse.migrations
index f6de06da5..a065cdf68 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/clickhouse/idx_clickhouse.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/clickhouse/idx_clickhouse.migrations
@@ -1,6 +1,6 @@
 193400547,      1.0__initial.sql
-1036221356,     1.1.sql
+-1021430823,    1.1.sql
 688811494,      1.2__dropsFor_1.1.sql
 1015552567,     1.3.sql
--252580551,     1.4__dropsFor_1.3.sql
+1436420661,     1.4__dropsFor_1.3.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/cockroach/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/cockroach/1.1.sql
index a450821e0..b0c756a54 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/cockroach/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/cockroach/1.1.sql
@@ -33,6 +33,13 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer generated by default as identity not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer generated by default as identity not null,
   test_byte16                   bytea,
@@ -217,6 +224,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/cockroach/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/cockroach/1.4__dropsFor_1.3.sql
index 099bdbad8..b2cc3a496 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/cockroach/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/cockroach/1.4__dropsFor_1.3.sql
@@ -24,6 +24,8 @@ drop table if exists drop_ref_many cascade;
 drop sequence if exists drop_ref_many_seq;
 drop table if exists drop_ref_one cascade;
 drop sequence if exists drop_ref_one_seq;
+drop table if exists drop_ref_one_to_one cascade;
+drop sequence if exists drop_ref_one_to_one_seq;
 drop table if exists migtest_e_test_binary cascade;
 drop sequence if exists migtest_e_test_binary_seq;
 drop table if exists migtest_e_test_json cascade;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/cockroach/idx_cockroach.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/cockroach/idx_cockroach.migrations
index 8688ba882..1a7b300b6 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/cockroach/idx_cockroach.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/cockroach/idx_cockroach.migrations
@@ -1,7 +1,7 @@
 1434934404,     1.0__initial.sql
--1445091875,    1.1.sql
+-645855838,     1.1.sql
 856096334,      1.2__dropsFor_1.1.sql
 -279468991,     1.3.sql
--1398154763,    1.4__dropsFor_1.3.sql
+-1416035730,    1.4__dropsFor_1.3.sql
 561281075,      R__order_views.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/db2fori/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/db2fori/1.1.sql
index cff474433..354006bde 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/db2fori/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/db2fori/1.1.sql
@@ -107,6 +107,12 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer generated by default as identity not null,
+  parent_id                     integer,
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer generated by default as identity not null,
   test_byte16                   varbinary(16),
@@ -306,6 +312,7 @@ alter table table_history add column "select" varchar(255);
 alter table table_history add column textfield2 varchar(255);
 call sysproc.admin_cmd('reorg table table_history');
 -- apply post alter
+create unique index uq_drop_ref_one_to_one_parent_id on drop_ref_one_to_one(parent_id) exclude null keys;
 alter table migtest_e_basic add constraint ck_migtest_e_basic_status check ( status in ('N','A','I','?'));
 create unique index uq_migtest_e_basic_description on migtest_e_basic(description) exclude null keys;
 update migtest_e_basic set new_boolean_field = old_boolean;
@@ -337,6 +344,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/db2fori/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/db2fori/1.4__dropsFor_1.3.sql
index 38f8b7c59..d103a5885 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/db2fori/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/db2fori/1.4__dropsFor_1.3.sql
@@ -73,6 +73,14 @@ if exists (select seqschema from syscat.sequences where seqschema = current_sche
   execute stmt;
 end if;
 end$$;
+drop table drop_ref_one_to_one;
+delimiter $$
+begin
+if exists (select seqschema from syscat.sequences where seqschema = current_schema and ucase(seqname) = 'DROP_REF_ONE_TO_ONE_SEQ') then
+  prepare stmt from 'drop sequence drop_ref_one_to_one_seq';
+  execute stmt;
+end if;
+end$$;
 drop table migtest_e_test_binary;
 delimiter $$
 begin
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/db2fori/idx_db2.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/db2fori/idx_db2.migrations
index e080749fa..32546b4dc 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/db2fori/idx_db2.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/db2fori/idx_db2.migrations
@@ -1,7 +1,7 @@
 -1467839063,    1.0__initial.sql
-1392865974,     1.1.sql
+638526085,      1.1.sql
 -1187336846,    1.2__dropsFor_1.1.sql
 -1811865535,    1.3.sql
-1864105401,     1.4__dropsFor_1.3.sql
+2087595324,     1.4__dropsFor_1.3.sql
 561281075,      R__order_views.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/db2legacy/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/db2legacy/1.1.sql
index 08008a18a..6885cdf6a 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/db2legacy/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/db2legacy/1.1.sql
@@ -33,6 +33,13 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer auto_increment not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer auto_increment not null,
   test_byte16                   varbinary(16),
@@ -220,6 +227,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/db2legacy/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/db2legacy/1.4__dropsFor_1.3.sql
index d66b81f56..54c4cfbfb 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/db2legacy/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/db2legacy/1.4__dropsFor_1.3.sql
@@ -21,6 +21,7 @@ drop table if exists drop_main;
 drop table if exists drop_main_drop_ref_many;
 drop table if exists drop_ref_many;
 drop table if exists drop_ref_one;
+drop table if exists drop_ref_one_to_one;
 drop table if exists migtest_e_test_binary;
 drop table if exists migtest_e_test_json;
 drop table if exists migtest_e_test_lob;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/db2legacy/idx_generic.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/db2legacy/idx_generic.migrations
index 4adfd909a..14d94ff8a 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/db2legacy/idx_generic.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/db2legacy/idx_generic.migrations
@@ -1,6 +1,6 @@
 -1547037623,    1.0__initial.sql
-275373095,      1.1.sql
+563570833,      1.1.sql
 688811494,      1.2__dropsFor_1.1.sql
 674925120,      1.3.sql
--252580551,     1.4__dropsFor_1.3.sql
+1436420661,     1.4__dropsFor_1.3.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/db2luw/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/db2luw/1.1.sql
index be023a9de..de6745d0b 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/db2luw/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/db2luw/1.1.sql
@@ -107,6 +107,12 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer generated by default as identity not null,
+  parent_id                     integer,
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer generated by default as identity not null,
   test_byte16                   varbinary(16),
@@ -306,6 +312,7 @@ alter table table_history add column "select" varchar(255);
 alter table table_history add column textfield2 varchar(255);
 call sysproc.admin_cmd('reorg table table_history');
 -- apply post alter
+create unique index uq_drop_ref_one_to_one_parent_id on drop_ref_one_to_one(parent_id) exclude null keys;
 alter table migtest_e_basic add constraint ck_migtest_e_basic_status check ( status in ('N','A','I','?'));
 create unique index uq_migtest_e_basic_description on migtest_e_basic(description) exclude null keys;
 update migtest_e_basic set new_boolean_field = old_boolean;
@@ -337,6 +344,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/db2luw/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/db2luw/1.4__dropsFor_1.3.sql
index 38f8b7c59..d103a5885 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/db2luw/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/db2luw/1.4__dropsFor_1.3.sql
@@ -73,6 +73,14 @@ if exists (select seqschema from syscat.sequences where seqschema = current_sche
   execute stmt;
 end if;
 end$$;
+drop table drop_ref_one_to_one;
+delimiter $$
+begin
+if exists (select seqschema from syscat.sequences where seqschema = current_schema and ucase(seqname) = 'DROP_REF_ONE_TO_ONE_SEQ') then
+  prepare stmt from 'drop sequence drop_ref_one_to_one_seq';
+  execute stmt;
+end if;
+end$$;
 drop table migtest_e_test_binary;
 delimiter $$
 begin
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/db2luw/idx_db2.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/db2luw/idx_db2.migrations
index c2926700d..e3d6882e5 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/db2luw/idx_db2.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/db2luw/idx_db2.migrations
@@ -1,8 +1,8 @@
 1307787475,     I__create_tablespaces.sql
 2058232717,     1.0__initial.sql
-372361421,      1.1.sql
+-1168453954,    1.1.sql
 -1187336846,    1.2__dropsFor_1.1.sql
 469192394,      1.3.sql
-1864105401,     1.4__dropsFor_1.3.sql
+2087595324,     1.4__dropsFor_1.3.sql
 561281075,      R__order_views.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/db2zos/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/db2zos/1.1.sql
index be023a9de..de6745d0b 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/db2zos/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/db2zos/1.1.sql
@@ -107,6 +107,12 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer generated by default as identity not null,
+  parent_id                     integer,
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer generated by default as identity not null,
   test_byte16                   varbinary(16),
@@ -306,6 +312,7 @@ alter table table_history add column "select" varchar(255);
 alter table table_history add column textfield2 varchar(255);
 call sysproc.admin_cmd('reorg table table_history');
 -- apply post alter
+create unique index uq_drop_ref_one_to_one_parent_id on drop_ref_one_to_one(parent_id) exclude null keys;
 alter table migtest_e_basic add constraint ck_migtest_e_basic_status check ( status in ('N','A','I','?'));
 create unique index uq_migtest_e_basic_description on migtest_e_basic(description) exclude null keys;
 update migtest_e_basic set new_boolean_field = old_boolean;
@@ -337,6 +344,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/db2zos/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/db2zos/1.4__dropsFor_1.3.sql
index 38f8b7c59..d103a5885 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/db2zos/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/db2zos/1.4__dropsFor_1.3.sql
@@ -73,6 +73,14 @@ if exists (select seqschema from syscat.sequences where seqschema = current_sche
   execute stmt;
 end if;
 end$$;
+drop table drop_ref_one_to_one;
+delimiter $$
+begin
+if exists (select seqschema from syscat.sequences where seqschema = current_schema and ucase(seqname) = 'DROP_REF_ONE_TO_ONE_SEQ') then
+  prepare stmt from 'drop sequence drop_ref_one_to_one_seq';
+  execute stmt;
+end if;
+end$$;
 drop table migtest_e_test_binary;
 delimiter $$
 begin
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/db2zos/idx_db2.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/db2zos/idx_db2.migrations
index 930929aa3..ac0ae9443 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/db2zos/idx_db2.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/db2zos/idx_db2.migrations
@@ -1,7 +1,7 @@
 2058232717,     1.0__initial.sql
-372361421,      1.1.sql
+-1168453954,    1.1.sql
 -1187336846,    1.2__dropsFor_1.1.sql
 469192394,      1.3.sql
-1864105401,     1.4__dropsFor_1.3.sql
+2087595324,     1.4__dropsFor_1.3.sql
 561281075,      R__order_views.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/generic/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/generic/1.1.sql
index 08008a18a..6885cdf6a 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/generic/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/generic/1.1.sql
@@ -33,6 +33,13 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer auto_increment not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer auto_increment not null,
   test_byte16                   varbinary(16),
@@ -220,6 +227,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/generic/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/generic/1.4__dropsFor_1.3.sql
index d66b81f56..54c4cfbfb 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/generic/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/generic/1.4__dropsFor_1.3.sql
@@ -21,6 +21,7 @@ drop table if exists drop_main;
 drop table if exists drop_main_drop_ref_many;
 drop table if exists drop_ref_many;
 drop table if exists drop_ref_one;
+drop table if exists drop_ref_one_to_one;
 drop table if exists migtest_e_test_binary;
 drop table if exists migtest_e_test_json;
 drop table if exists migtest_e_test_lob;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/generic/idx_generic.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/generic/idx_generic.migrations
index 4adfd909a..14d94ff8a 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/generic/idx_generic.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/generic/idx_generic.migrations
@@ -1,6 +1,6 @@
 -1547037623,    1.0__initial.sql
-275373095,      1.1.sql
+563570833,      1.1.sql
 688811494,      1.2__dropsFor_1.1.sql
 674925120,      1.3.sql
--252580551,     1.4__dropsFor_1.3.sql
+1436420661,     1.4__dropsFor_1.3.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/h2/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/h2/1.1.sql
index 5b15b853f..a5e3ff8dc 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/h2/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/h2/1.1.sql
@@ -33,6 +33,13 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer generated by default as identity not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer generated by default as identity not null,
   test_byte16                   varbinary(16),
@@ -264,6 +271,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/h2/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/h2/1.4__dropsFor_1.3.sql
index 7dd46268a..840a5dd95 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/h2/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/h2/1.4__dropsFor_1.3.sql
@@ -50,6 +50,8 @@ drop table if exists drop_ref_many;
 drop sequence if exists drop_ref_many_seq;
 drop table if exists drop_ref_one;
 drop sequence if exists drop_ref_one_seq;
+drop table if exists drop_ref_one_to_one;
+drop sequence if exists drop_ref_one_to_one_seq;
 drop table if exists migtest_e_test_binary;
 drop sequence if exists migtest_e_test_binary_seq;
 drop table if exists migtest_e_test_json;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/h2/idx_h2.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/h2/idx_h2.migrations
index 1a613da0d..46aefebb6 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/h2/idx_h2.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/h2/idx_h2.migrations
@@ -1,8 +1,8 @@
 -1854589550,    1.0__initial.sql
--505431855,     1.1.sql
+768680300,      1.1.sql
 1579867974,     1.2__dropsFor_1.1.sql
 64466326,       1.3.sql
--232694612,     1.4__dropsFor_1.3.sql
+334448611,      1.4__dropsFor_1.3.sql
 783227075,      R__multi_comments.sql
 561281075,      R__order_views.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/hana/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/hana/1.1.sql
index 84800ffc7..af98ef4af 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/hana/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/hana/1.1.sql
@@ -81,6 +81,13 @@ create column table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create column table drop_ref_one_to_one (
+  id                            integer generated by default as identity not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create column table migtest_e_test_binary (
   id                            integer generated by default as identity not null,
   test_byte16                   varbinary(16),
@@ -295,6 +302,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 -- explicit index "ix_drop_ref_one_parent_id" for single column "parent_id" of table "drop_ref_one" is not necessary;
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 -- explicit index "ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c" for single column "migtest_mtm_c_id" of table "migtest_mtm_c_migtest_mtm_m" is not necessary;
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/hana/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/hana/1.4__dropsFor_1.3.sql
index ba054e40e..1d0778757 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/hana/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/hana/1.4__dropsFor_1.3.sql
@@ -39,6 +39,7 @@ drop table drop_main cascade;
 drop table drop_main_drop_ref_many cascade;
 drop table drop_ref_many cascade;
 drop table drop_ref_one cascade;
+drop table drop_ref_one_to_one cascade;
 drop table migtest_e_test_binary cascade;
 drop table migtest_e_test_json cascade;
 drop table migtest_e_test_lob cascade;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/hana/idx_hana.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/hana/idx_hana.migrations
index 825081509..47cac48d2 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/hana/idx_hana.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/hana/idx_hana.migrations
@@ -1,8 +1,8 @@
 -745347271,     I__create_procs.sql
 -2017770851,    1.0__initial.sql
-2126049978,     1.1.sql
+-475843596,     1.1.sql
 1535221752,     1.2__dropsFor_1.1.sql
 1459381570,     1.3.sql
--490709749,     1.4__dropsFor_1.3.sql
+1613562845,     1.4__dropsFor_1.3.sql
 1906063401,     R__order_views_hana.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/hsqldb/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/hsqldb/1.1.sql
index db5e03b99..cde67e99a 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/hsqldb/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/hsqldb/1.1.sql
@@ -33,6 +33,13 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer generated by default as identity (start with 1)  not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer generated by default as identity (start with 1)  not null,
   test_byte16                   varbinary(16),
@@ -220,6 +227,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/hsqldb/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/hsqldb/1.4__dropsFor_1.3.sql
index 42ed7a01d..564997379 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/hsqldb/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/hsqldb/1.4__dropsFor_1.3.sql
@@ -24,6 +24,8 @@ drop table if exists drop_ref_many;
 drop sequence if exists drop_ref_many_seq;
 drop table if exists drop_ref_one;
 drop sequence if exists drop_ref_one_seq;
+drop table if exists drop_ref_one_to_one;
+drop sequence if exists drop_ref_one_to_one_seq;
 drop table if exists migtest_e_test_binary;
 drop sequence if exists migtest_e_test_binary_seq;
 drop table if exists migtest_e_test_json;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/hsqldb/idx_hsqldb.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/hsqldb/idx_hsqldb.migrations
index f8ca1056c..c0d8fb075 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/hsqldb/idx_hsqldb.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/hsqldb/idx_hsqldb.migrations
@@ -1,7 +1,7 @@
 1833930558,     1.0__initial.sql
--432003541,     1.1.sql
+277065890,      1.1.sql
 -848622216,     1.2__dropsFor_1.1.sql
 -1921508585,    1.3.sql
--1547659386,    1.4__dropsFor_1.3.sql
+-1765256531,    1.4__dropsFor_1.3.sql
 861001272,      R__order_views_hsqldb.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb-noprocs/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb-noprocs/1.1.sql
index 13a754cea..0199128d8 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb-noprocs/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb-noprocs/1.1.sql
@@ -30,6 +30,13 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer auto_increment not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer auto_increment not null,
   test_byte16                   varbinary(16),
@@ -209,6 +216,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb-noprocs/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb-noprocs/1.4__dropsFor_1.3.sql
index 81e4368e2..d550977b0 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb-noprocs/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb-noprocs/1.4__dropsFor_1.3.sql
@@ -27,6 +27,8 @@ drop table if exists drop_ref_many;
 drop sequence if exists drop_ref_many_seq;
 drop table if exists drop_ref_one;
 drop sequence if exists drop_ref_one_seq;
+drop table if exists drop_ref_one_to_one;
+drop sequence if exists drop_ref_one_to_one_seq;
 drop table if exists migtest_e_test_binary;
 drop sequence if exists migtest_e_test_binary_seq;
 drop table if exists migtest_e_test_json;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb-noprocs/idx_mariadb.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb-noprocs/idx_mariadb.migrations
index 09c4f565f..e6c87869a 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb-noprocs/idx_mariadb.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb-noprocs/idx_mariadb.migrations
@@ -1,7 +1,7 @@
 -2111548334,    1.0__initial.sql
-1717242095,     1.1.sql
+1085383251,     1.1.sql
 919151678,      1.2__dropsFor_1.1.sql
 -413458006,     1.3.sql
--177212756,     1.4__dropsFor_1.3.sql
+-924292968,     1.4__dropsFor_1.3.sql
 561281075,      R__order_views.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb/1.1.sql
index 13a754cea..0199128d8 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb/1.1.sql
@@ -30,6 +30,13 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer auto_increment not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer auto_increment not null,
   test_byte16                   varbinary(16),
@@ -209,6 +216,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb/1.4__dropsFor_1.3.sql
index 2e57704e8..5e501fc5e 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb/1.4__dropsFor_1.3.sql
@@ -27,6 +27,8 @@ drop table if exists drop_ref_many;
 drop sequence if exists drop_ref_many_seq;
 drop table if exists drop_ref_one;
 drop sequence if exists drop_ref_one_seq;
+drop table if exists drop_ref_one_to_one;
+drop sequence if exists drop_ref_one_to_one_seq;
 drop table if exists migtest_e_test_binary;
 drop sequence if exists migtest_e_test_binary_seq;
 drop table if exists migtest_e_test_json;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb/idx_mariadb.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb/idx_mariadb.migrations
index 784e32fd0..365fded3a 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb/idx_mariadb.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/mariadb/idx_mariadb.migrations
@@ -1,8 +1,8 @@
 -1933396282,    I__create_procs.sql
 -2111548334,    1.0__initial.sql
-1717242095,     1.1.sql
+1085383251,     1.1.sql
 1187950993,     1.2__dropsFor_1.1.sql
 -413458006,     1.3.sql
--1494509099,    1.4__dropsFor_1.3.sql
+-298825700,     1.4__dropsFor_1.3.sql
 561281075,      R__order_views.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/model/1.1.model.xml b/ebean-test/src/test/resources/migrationtest/dbmigration/model/1.1.model.xml
index d23d982ee..4fded216b 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/model/1.1.model.xml
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/model/1.1.model.xml
@@ -29,6 +29,10 @@
             <column name="id" type="integer" primaryKey="true"/>
             <column name="parent_id" type="integer" references="drop_main.id" foreignKeyName="fk_drop_ref_one_parent_id" foreignKeyIndex="ix_drop_ref_one_parent_id"/>
         </createTable>
+        <createTable name="drop_ref_one_to_one" pkName="pk_drop_ref_one_to_one">
+            <column name="id" type="integer" primaryKey="true"/>
+            <column name="parent_id" type="integer" uniqueOneToOne="uq_drop_ref_one_to_one_parent_id" references="drop_main.id" foreignKeyName="fk_drop_ref_one_to_one_parent_id"/>
+        </createTable>
         <alterColumn columnName="status" tableName="migtest_e_basic" currentType="varchar(1)" defaultValue="'A'" notnull="true" currentNotnull="false" checkConstraint="check ( status in ('N','A','I','?'))" checkConstraintName="ck_migtest_e_basic_status"/>
         <alterColumn columnName="status2" tableName="migtest_e_basic" type="varchar(127)" currentType="varchar(1)" defaultValue="DROP DEFAULT" notnull="false" currentNotnull="true" dropCheckConstraint="ck_migtest_e_basic_status2"/>
         <alterColumn columnName="description" tableName="migtest_e_basic" unique="uq_migtest_e_basic_description">
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/model/1.3.model.xml b/ebean-test/src/test/resources/migrationtest/dbmigration/model/1.3.model.xml
index bd902b317..560192cc9 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/model/1.3.model.xml
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/model/1.3.model.xml
@@ -94,6 +94,7 @@
         <dropTable name="drop_main_drop_ref_many"/>
         <dropTable name="drop_ref_many" sequenceCol="id"/>
         <dropTable name="drop_ref_one" sequenceCol="id"/>
+        <dropTable name="drop_ref_one_to_one" sequenceCol="id"/>
         <dropTable name="migtest_e_test_binary" sequenceCol="id"/>
         <dropTable name="migtest_e_test_json" sequenceCol="id"/>
         <dropTable name="migtest_e_test_lob" sequenceCol="id"/>
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/model/1.4__dropsFor_1.3.model.xml b/ebean-test/src/test/resources/migrationtest/dbmigration/model/1.4__dropsFor_1.3.model.xml
index 84b6f2c41..53fefa911 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/model/1.4__dropsFor_1.3.model.xml
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/model/1.4__dropsFor_1.3.model.xml
@@ -22,6 +22,7 @@
         <dropTable name="drop_main_drop_ref_many"/>
         <dropTable name="drop_ref_many" sequenceCol="id"/>
         <dropTable name="drop_ref_one" sequenceCol="id"/>
+        <dropTable name="drop_ref_one_to_one" sequenceCol="id"/>
         <dropTable name="migtest_e_test_binary" sequenceCol="id"/>
         <dropTable name="migtest_e_test_json" sequenceCol="id"/>
         <dropTable name="migtest_e_test_lob" sequenceCol="id"/>
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/mysql/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/mysql/1.1.sql
index 210723440..8b37ed409 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/mysql/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/mysql/1.1.sql
@@ -30,6 +30,13 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer auto_increment not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer auto_increment not null,
   test_byte16                   varbinary(16),
@@ -327,6 +334,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/mysql/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/mysql/1.4__dropsFor_1.3.sql
index 02bf03425..2849d5398 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/mysql/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/mysql/1.4__dropsFor_1.3.sql
@@ -81,6 +81,7 @@ drop table if exists drop_main;
 drop table if exists drop_main_drop_ref_many;
 drop table if exists drop_ref_many;
 drop table if exists drop_ref_one;
+drop table if exists drop_ref_one_to_one;
 drop table if exists migtest_e_test_binary;
 drop table if exists migtest_e_test_json;
 drop table if exists migtest_e_test_lob;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/mysql/idx_mysql.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/mysql/idx_mysql.migrations
index 84edad999..88c675441 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/mysql/idx_mysql.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/mysql/idx_mysql.migrations
@@ -1,8 +1,8 @@
 -1933396282,    I__create_procs.sql
 1980830787,     1.0__initial.sql
--847541300,     1.1.sql
+-151422898,     1.1.sql
 -1097227916,    1.2__dropsFor_1.1.sql
 141196883,      1.3.sql
-1044119359,     1.4__dropsFor_1.3.sql
+261977585,      1.4__dropsFor_1.3.sql
 561281075,      R__order_views.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/mysql55/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/mysql55/1.1.sql
index 210723440..8b37ed409 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/mysql55/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/mysql55/1.1.sql
@@ -30,6 +30,13 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer auto_increment not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer auto_increment not null,
   test_byte16                   varbinary(16),
@@ -327,6 +334,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/mysql55/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/mysql55/1.4__dropsFor_1.3.sql
index 02bf03425..2849d5398 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/mysql55/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/mysql55/1.4__dropsFor_1.3.sql
@@ -81,6 +81,7 @@ drop table if exists drop_main;
 drop table if exists drop_main_drop_ref_many;
 drop table if exists drop_ref_many;
 drop table if exists drop_ref_one;
+drop table if exists drop_ref_one_to_one;
 drop table if exists migtest_e_test_binary;
 drop table if exists migtest_e_test_json;
 drop table if exists migtest_e_test_lob;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/mysql55/idx_mysql.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/mysql55/idx_mysql.migrations
index 69f8a0317..6b5f289f7 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/mysql55/idx_mysql.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/mysql55/idx_mysql.migrations
@@ -1,8 +1,8 @@
 -1933396282,    I__create_procs.sql
 369577572,      1.0__initial.sql
--847541300,     1.1.sql
+-151422898,     1.1.sql
 -1097227916,    1.2__dropsFor_1.1.sql
 141196883,      1.3.sql
-1044119359,     1.4__dropsFor_1.3.sql
+261977585,      1.4__dropsFor_1.3.sql
 561281075,      R__order_views.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/nuodb/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/nuodb/1.1.sql
index b1e603bc7..ab07e1cc9 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/nuodb/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/nuodb/1.1.sql
@@ -33,6 +33,13 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer generated by default as identity not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer generated by default as identity not null,
   test_byte16                   varbinary(16),
@@ -351,6 +358,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id);
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id);
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id);
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/nuodb/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/nuodb/1.4__dropsFor_1.3.sql
index 1eda03867..9d8eb8bf6 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/nuodb/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/nuodb/1.4__dropsFor_1.3.sql
@@ -90,6 +90,8 @@ drop table if exists drop_ref_many;
 drop sequence if exists drop_ref_many_seq;
 drop table if exists drop_ref_one;
 drop sequence if exists drop_ref_one_seq;
+drop table if exists drop_ref_one_to_one;
+drop sequence if exists drop_ref_one_to_one_seq;
 drop table if exists migtest_e_test_binary;
 drop sequence if exists migtest_e_test_binary_seq;
 drop table if exists migtest_e_test_json;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/nuodb/idx_nuodb.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/nuodb/idx_nuodb.migrations
index 85b584cd4..3be3ee1e3 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/nuodb/idx_nuodb.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/nuodb/idx_nuodb.migrations
@@ -1,7 +1,7 @@
 390216918,      1.0__initial.sql
--303196611,     1.1.sql
+-1064172809,    1.1.sql
 1530685455,     1.2__dropsFor_1.1.sql
 -956168377,     1.3.sql
-1047623430,     1.4__dropsFor_1.3.sql
+-381446847,     1.4__dropsFor_1.3.sql
 561281075,      R__order_views.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/oracle/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/oracle/1.1.sql
index c222cc8a5..e94b9ac47 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/oracle/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/oracle/1.1.sql
@@ -78,6 +78,13 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            number(10) generated by default as identity not null,
+  parent_id                     number(10),
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            number(10) generated by default as identity not null,
   test_byte16                   raw(16),
@@ -265,6 +272,8 @@ alter table drop_main_drop_ref_many add constraint fk_drp_mn_drp_rf_mny_dr_joesl
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id);
 
+alter table drop_ref_one_to_one add constraint fk_drp_rf_n_t_n_prnt_d foreign key (parent_id) references drop_main (id);
+
 create index ix_mgtst_mtm_c_mgtst_mt_3ug4ok on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_mgtst_mtm_c_mgtst_mt_93awga foreign key (migtest_mtm_c_id) references migtest_mtm_c (id);
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/oracle/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/oracle/1.4__dropsFor_1.3.sql
index 2a70d5211..c1a01787c 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/oracle/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/oracle/1.4__dropsFor_1.3.sql
@@ -51,6 +51,17 @@ exception
   when expected_error then null;
 end;
 $$;
+drop table drop_ref_one_to_one cascade constraints purge;
+delimiter $$
+declare
+  expected_error exception;
+  pragma exception_init(expected_error, -2289);
+begin
+  execute immediate 'drop sequence drop_ref_one_to_one_seq';
+exception
+  when expected_error then null;
+end;
+$$;
 drop table migtest_e_test_binary cascade constraints purge;
 delimiter $$
 declare
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/oracle/idx_oracle.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/oracle/idx_oracle.migrations
index 7aff21509..4d4d33fa7 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/oracle/idx_oracle.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/oracle/idx_oracle.migrations
@@ -1,8 +1,8 @@
 1757923548,     1.0__initial.sql
--1862781653,    1.1.sql
+-130678137,     1.1.sql
 930172034,      1.2__dropsFor_1.1.sql
 -647790612,     1.3.sql
--116456403,     1.4__dropsFor_1.3.sql
+1480920634,     1.4__dropsFor_1.3.sql
 1357801733,     R__oracle_only_views.sql
 561281075,      R__order_views.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/oracle11/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/oracle11/1.1.sql
index 59d29e649..c30c11571 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/oracle11/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/oracle11/1.1.sql
@@ -81,6 +81,14 @@ create table drop_ref_one (
 );
 create sequence drop_ref_one_seq;
 
+create table drop_ref_one_to_one (
+  id                            number(10) not null,
+  parent_id                     number(10),
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+create sequence drop_ref_one_to_one_seq;
+
 create table migtest_e_test_binary (
   id                            number(10) not null,
   test_byte16                   raw(16),
@@ -273,6 +281,8 @@ alter table drop_main_drop_ref_many add constraint fk_drp_mn_drp_rf_mny_dr_joesl
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id);
 
+alter table drop_ref_one_to_one add constraint fk_drp_rf_n_t_n_prnt_d foreign key (parent_id) references drop_main (id);
+
 create index ix_mgtst_mtm_c_mgtst_mt_3ug4ok on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_mgtst_mtm_c_mgtst_mt_93awga foreign key (migtest_mtm_c_id) references migtest_mtm_c (id);
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/oracle11/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/oracle11/1.4__dropsFor_1.3.sql
index 2a70d5211..c1a01787c 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/oracle11/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/oracle11/1.4__dropsFor_1.3.sql
@@ -51,6 +51,17 @@ exception
   when expected_error then null;
 end;
 $$;
+drop table drop_ref_one_to_one cascade constraints purge;
+delimiter $$
+declare
+  expected_error exception;
+  pragma exception_init(expected_error, -2289);
+begin
+  execute immediate 'drop sequence drop_ref_one_to_one_seq';
+exception
+  when expected_error then null;
+end;
+$$;
 drop table migtest_e_test_binary cascade constraints purge;
 delimiter $$
 declare
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/oracle11/idx_oracle.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/oracle11/idx_oracle.migrations
index e1d314b8c..b34cc6bdd 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/oracle11/idx_oracle.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/oracle11/idx_oracle.migrations
@@ -1,8 +1,8 @@
 -1422254768,    1.0__initial.sql
-661141209,      1.1.sql
+1418539051,     1.1.sql
 930172034,      1.2__dropsFor_1.1.sql
 1369863782,     1.3.sql
--116456403,     1.4__dropsFor_1.3.sql
+1480920634,     1.4__dropsFor_1.3.sql
 1357801733,     R__oracle_only_views.sql
 561281075,      R__order_views.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/postgres/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/postgres/1.1.sql
index e116daece..331821319 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/postgres/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/postgres/1.1.sql
@@ -36,6 +36,13 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer generated by default as identity not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer generated by default as identity not null,
   test_byte16                   bytea,
@@ -422,6 +429,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/postgres/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/postgres/1.4__dropsFor_1.3.sql
index 28f59c8e6..784d289fb 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/postgres/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/postgres/1.4__dropsFor_1.3.sql
@@ -120,6 +120,8 @@ drop table if exists drop_ref_many cascade;
 drop sequence if exists drop_ref_many_seq;
 drop table if exists drop_ref_one cascade;
 drop sequence if exists drop_ref_one_seq;
+drop table if exists drop_ref_one_to_one cascade;
+drop sequence if exists drop_ref_one_to_one_seq;
 drop table if exists migtest_e_test_binary cascade;
 drop sequence if exists migtest_e_test_binary_seq;
 drop table if exists migtest_e_test_json cascade;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/postgres/idx_postgres.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/postgres/idx_postgres.migrations
index b919977c3..b615a9879 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/postgres/idx_postgres.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/postgres/idx_postgres.migrations
@@ -1,8 +1,8 @@
 1942370812,     1.0__initial.sql
--150823045,     1.1.sql
+-1945546744,    1.1.sql
 -261111052,     1.2__dropsFor_1.1.sql
 788727457,      1.3.sql
--1352224731,    1.4__dropsFor_1.3.sql
+1188958800,     1.4__dropsFor_1.3.sql
 783227075,      R__multi_comments.sql
 561281075,      R__order_views.sql
 283077354,      R__pg_indexes.sql
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/postgres9/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/postgres9/1.1.sql
index dd0d1827c..4b29b2691 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/postgres9/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/postgres9/1.1.sql
@@ -36,6 +36,13 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            serial not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            serial not null,
   test_byte16                   bytea,
@@ -422,6 +429,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/postgres9/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/postgres9/1.4__dropsFor_1.3.sql
index 28f59c8e6..784d289fb 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/postgres9/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/postgres9/1.4__dropsFor_1.3.sql
@@ -120,6 +120,8 @@ drop table if exists drop_ref_many cascade;
 drop sequence if exists drop_ref_many_seq;
 drop table if exists drop_ref_one cascade;
 drop sequence if exists drop_ref_one_seq;
+drop table if exists drop_ref_one_to_one cascade;
+drop sequence if exists drop_ref_one_to_one_seq;
 drop table if exists migtest_e_test_binary cascade;
 drop sequence if exists migtest_e_test_binary_seq;
 drop table if exists migtest_e_test_json cascade;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/postgres9/idx_postgres.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/postgres9/idx_postgres.migrations
index e2da8048e..d351b282a 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/postgres9/idx_postgres.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/postgres9/idx_postgres.migrations
@@ -1,8 +1,8 @@
 -1015076364,    1.0__initial.sql
-328269371,      1.1.sql
+-1624208025,    1.1.sql
 -261111052,     1.2__dropsFor_1.1.sql
 -1811829200,    1.3.sql
--1352224731,    1.4__dropsFor_1.3.sql
+1188958800,     1.4__dropsFor_1.3.sql
 783227075,      R__multi_comments.sql
 561281075,      R__order_views.sql
 283077354,      R__pg_indexes.sql
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlanywhere/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlanywhere/1.1.sql
index 3383de4ad..d5db941ff 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlanywhere/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlanywhere/1.1.sql
@@ -33,6 +33,13 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer auto_increment not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer auto_increment not null,
   test_byte16                   varbinary(16),
@@ -220,6 +227,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlanywhere/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlanywhere/1.4__dropsFor_1.3.sql
index d66b81f56..54c4cfbfb 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlanywhere/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlanywhere/1.4__dropsFor_1.3.sql
@@ -21,6 +21,7 @@ drop table if exists drop_main;
 drop table if exists drop_main_drop_ref_many;
 drop table if exists drop_ref_many;
 drop table if exists drop_ref_one;
+drop table if exists drop_ref_one_to_one;
 drop table if exists migtest_e_test_binary;
 drop table if exists migtest_e_test_json;
 drop table if exists migtest_e_test_lob;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlanywhere/idx_sqlanywhere.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlanywhere/idx_sqlanywhere.migrations
index e5f698839..e8b8aa9ca 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlanywhere/idx_sqlanywhere.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlanywhere/idx_sqlanywhere.migrations
@@ -1,6 +1,6 @@
 -391639901,     1.0__initial.sql
-974884972,      1.1.sql
+1808590378,     1.1.sql
 688811494,      1.2__dropsFor_1.1.sql
 1199670482,     1.3.sql
--252580551,     1.4__dropsFor_1.3.sql
+1436420661,     1.4__dropsFor_1.3.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlite/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlite/1.1.sql
index 0560f36e7..3229b641f 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlite/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlite/1.1.sql
@@ -36,6 +36,14 @@ create table drop_ref_one (
   foreign key (parent_id) references drop_main (id) on delete restrict on update restrict
 );
 
+create table drop_ref_one_to_one (
+  id                            integer not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id),
+  foreign key (parent_id) references drop_main (id) on delete restrict on update restrict
+);
+
 create table migtest_e_test_binary (
   id                            integer not null,
   test_byte16                   varbinary(16),
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlite/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlite/1.4__dropsFor_1.3.sql
index d66b81f56..54c4cfbfb 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlite/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlite/1.4__dropsFor_1.3.sql
@@ -21,6 +21,7 @@ drop table if exists drop_main;
 drop table if exists drop_main_drop_ref_many;
 drop table if exists drop_ref_many;
 drop table if exists drop_ref_one;
+drop table if exists drop_ref_one_to_one;
 drop table if exists migtest_e_test_binary;
 drop table if exists migtest_e_test_json;
 drop table if exists migtest_e_test_lob;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlite/idx_sqlite.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlite/idx_sqlite.migrations
index fe71e16d3..3e3e462d2 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlite/idx_sqlite.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlite/idx_sqlite.migrations
@@ -1,7 +1,7 @@
 -1527127682,    1.0__initial.sql
--321125092,     1.1.sql
+728006469,      1.1.sql
 688811494,      1.2__dropsFor_1.1.sql
 142780650,      1.3.sql
--252580551,     1.4__dropsFor_1.3.sql
+1436420661,     1.4__dropsFor_1.3.sql
 2034589659,     R__order_views_sqlite.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver16/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver16/1.1.sql
index 11db228e6..2bba9c7b9 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver16/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver16/1.1.sql
@@ -35,6 +35,12 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer identity(1,1) not null,
+  parent_id                     integer,
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer identity(1,1) not null,
   test_byte16                   image,
@@ -219,6 +225,7 @@ alter table migtest_e_history6 alter column test_number2 integer;
 alter table migtest_e_softdelete add deleted bit default 0 not null;
 alter table migtest_oto_child add master_id bigint;
 -- apply post alter
+create unique nonclustered index uq_drop_ref_one_to_one_parent_id on drop_ref_one_to_one(parent_id) where parent_id is not null;
 alter table migtest_e_basic add constraint ck_migtest_e_basic_status check ( status in ('N','A','I','?'));
 create unique nonclustered index uq_migtest_e_basic_description on migtest_e_basic(description) where description is not null;
 update migtest_e_basic set new_boolean_field = old_boolean;
@@ -244,6 +251,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id);
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id);
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id);
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver16/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver16/1.4__dropsFor_1.3.sql
index 1595c2e4f..b2c3ff60a 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver16/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver16/1.4__dropsFor_1.3.sql
@@ -43,6 +43,8 @@ IF OBJECT_ID('drop_ref_many', 'U') IS NOT NULL drop table drop_ref_many;
 IF OBJECT_ID('drop_ref_many_seq', 'SO') IS NOT NULL drop sequence drop_ref_many_seq;
 IF OBJECT_ID('drop_ref_one', 'U') IS NOT NULL drop table drop_ref_one;
 IF OBJECT_ID('drop_ref_one_seq', 'SO') IS NOT NULL drop sequence drop_ref_one_seq;
+IF OBJECT_ID('drop_ref_one_to_one', 'U') IS NOT NULL drop table drop_ref_one_to_one;
+IF OBJECT_ID('drop_ref_one_to_one_seq', 'SO') IS NOT NULL drop sequence drop_ref_one_to_one_seq;
 IF OBJECT_ID('migtest_e_test_binary', 'U') IS NOT NULL drop table migtest_e_test_binary;
 IF OBJECT_ID('migtest_e_test_binary_seq', 'SO') IS NOT NULL drop sequence migtest_e_test_binary_seq;
 IF OBJECT_ID('migtest_e_test_json', 'U') IS NOT NULL drop table migtest_e_test_json;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver16/idx_sqlserver.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver16/idx_sqlserver.migrations
index c011a6900..161248043 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver16/idx_sqlserver.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver16/idx_sqlserver.migrations
@@ -1,8 +1,8 @@
 891357544,      I__create_procs.sql
 -1455820494,    1.0__initial.sql
--88313995,      1.1.sql
+-2020672101,    1.1.sql
 -1431095657,    1.2__dropsFor_1.1.sql
 1846195516,     1.3.sql
--225579996,     1.4__dropsFor_1.3.sql
+-1281693740,    1.4__dropsFor_1.3.sql
 1607822082,     R__order_views_mssql.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver17/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver17/1.1.sql
index b79765243..02edd6dbb 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver17/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver17/1.1.sql
@@ -38,6 +38,13 @@ create table drop_ref_one (
 );
 create sequence drop_ref_one_seq as bigint start with 1;
 
+create table drop_ref_one_to_one (
+  id                            integer not null,
+  parent_id                     integer,
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+create sequence drop_ref_one_to_one_seq as bigint start with 1;
+
 create table migtest_e_test_binary (
   id                            integer not null,
   test_byte16                   varbinary(16),
@@ -227,6 +234,7 @@ alter table migtest_e_history6 alter column test_number2 integer;
 alter table migtest_e_softdelete add deleted bit default 0 not null;
 alter table migtest_oto_child add master_id bigint;
 -- apply post alter
+create unique nonclustered index uq_drop_ref_one_to_one_parent_id on drop_ref_one_to_one(parent_id) where parent_id is not null;
 alter table migtest_e_basic add constraint ck_migtest_e_basic_status check ( status in ('N','A','I','?'));
 create unique nonclustered index uq_migtest_e_basic_description on migtest_e_basic(description) where description is not null;
 update migtest_e_basic set new_boolean_field = old_boolean;
@@ -252,6 +260,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id);
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id);
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id);
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver17/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver17/1.4__dropsFor_1.3.sql
index 1595c2e4f..b2c3ff60a 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver17/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver17/1.4__dropsFor_1.3.sql
@@ -43,6 +43,8 @@ IF OBJECT_ID('drop_ref_many', 'U') IS NOT NULL drop table drop_ref_many;
 IF OBJECT_ID('drop_ref_many_seq', 'SO') IS NOT NULL drop sequence drop_ref_many_seq;
 IF OBJECT_ID('drop_ref_one', 'U') IS NOT NULL drop table drop_ref_one;
 IF OBJECT_ID('drop_ref_one_seq', 'SO') IS NOT NULL drop sequence drop_ref_one_seq;
+IF OBJECT_ID('drop_ref_one_to_one', 'U') IS NOT NULL drop table drop_ref_one_to_one;
+IF OBJECT_ID('drop_ref_one_to_one_seq', 'SO') IS NOT NULL drop sequence drop_ref_one_to_one_seq;
 IF OBJECT_ID('migtest_e_test_binary', 'U') IS NOT NULL drop table migtest_e_test_binary;
 IF OBJECT_ID('migtest_e_test_binary_seq', 'SO') IS NOT NULL drop sequence migtest_e_test_binary_seq;
 IF OBJECT_ID('migtest_e_test_json', 'U') IS NOT NULL drop table migtest_e_test_json;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver17/idx_sqlserver.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver17/idx_sqlserver.migrations
index e843dc30d..004589b70 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver17/idx_sqlserver.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/sqlserver17/idx_sqlserver.migrations
@@ -1,8 +1,8 @@
 891357544,      I__create_procs.sql
 1574627056,     1.0__initial.sql
-1681608861,     1.1.sql
+1141454658,     1.1.sql
 -1431095657,    1.2__dropsFor_1.1.sql
 486442698,      1.3.sql
--225579996,     1.4__dropsFor_1.3.sql
+-1281693740,    1.4__dropsFor_1.3.sql
 1607822082,     R__order_views_mssql.sql
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/yugabyte/1.1.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/yugabyte/1.1.sql
index 64478fe81..c20522fc4 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/yugabyte/1.1.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/yugabyte/1.1.sql
@@ -33,6 +33,13 @@ create table drop_ref_one (
   constraint pk_drop_ref_one primary key (id)
 );
 
+create table drop_ref_one_to_one (
+  id                            integer generated by default as identity not null,
+  parent_id                     integer,
+  constraint uq_drop_ref_one_to_one_parent_id unique (parent_id),
+  constraint pk_drop_ref_one_to_one primary key (id)
+);
+
 create table migtest_e_test_binary (
   id                            integer generated by default as identity not null,
   test_byte16                   bytea,
@@ -421,6 +428,8 @@ alter table drop_main_drop_ref_many add constraint fk_drop_main_drop_ref_many_dr
 create index ix_drop_ref_one_parent_id on drop_ref_one (parent_id);
 alter table drop_ref_one add constraint fk_drop_ref_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
 
+alter table drop_ref_one_to_one add constraint fk_drop_ref_one_to_one_parent_id foreign key (parent_id) references drop_main (id) on delete restrict on update restrict;
+
 create index ix_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c on migtest_mtm_c_migtest_mtm_m (migtest_mtm_c_id);
 alter table migtest_mtm_c_migtest_mtm_m add constraint fk_migtest_mtm_c_migtest_mtm_m_migtest_mtm_c foreign key (migtest_mtm_c_id) references migtest_mtm_c (id) on delete restrict on update restrict;
 
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/yugabyte/1.4__dropsFor_1.3.sql b/ebean-test/src/test/resources/migrationtest/dbmigration/yugabyte/1.4__dropsFor_1.3.sql
index 28f59c8e6..784d289fb 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/yugabyte/1.4__dropsFor_1.3.sql
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/yugabyte/1.4__dropsFor_1.3.sql
@@ -120,6 +120,8 @@ drop table if exists drop_ref_many cascade;
 drop sequence if exists drop_ref_many_seq;
 drop table if exists drop_ref_one cascade;
 drop sequence if exists drop_ref_one_seq;
+drop table if exists drop_ref_one_to_one cascade;
+drop sequence if exists drop_ref_one_to_one_seq;
 drop table if exists migtest_e_test_binary cascade;
 drop sequence if exists migtest_e_test_binary_seq;
 drop table if exists migtest_e_test_json cascade;
diff --git a/ebean-test/src/test/resources/migrationtest/dbmigration/yugabyte/idx_yugabyte.migrations b/ebean-test/src/test/resources/migrationtest/dbmigration/yugabyte/idx_yugabyte.migrations
index a5907171d..a81041bae 100644
--- a/ebean-test/src/test/resources/migrationtest/dbmigration/yugabyte/idx_yugabyte.migrations
+++ b/ebean-test/src/test/resources/migrationtest/dbmigration/yugabyte/idx_yugabyte.migrations
@@ -1,7 +1,7 @@
 -1646972843,    1.0__initial.sql
-1912842724,     1.1.sql
+-698093883,     1.1.sql
 -261111052,     1.2__dropsFor_1.1.sql
 -526466104,     1.3.sql
--1352224731,    1.4__dropsFor_1.3.sql
+1188958800,     1.4__dropsFor_1.3.sql
 561281075,      R__order_views.sql