#2206 - Postgres DDL generation - for create index use "if not exists" clause

ebean-ddl-generator/src/main/java/io/ebeaninternal/dbmigration/ddlgeneration/platform/PlatformDdl.java

@@ -3,7 +3,6 @@ package io.ebeaninternal.dbmigration.ddlgeneration.platform;
 import io.ebean.annotation.ConstraintMode;
 import io.ebean.config.DatabaseConfig;
 import io.ebean.config.DbConstraintNaming;
-import io.ebean.config.ServerConfig;
 import io.ebean.config.dbplatform.DatabasePlatform;
 import io.ebean.config.dbplatform.DbDefaultValue;
 import io.ebean.config.dbplatform.DbIdentity;
@@ -113,6 +112,7 @@ public class PlatformDdl {
 
   protected String uniqueIndex = "unique";
   protected String indexConcurrent = "";
+  protected String createIndexIfNotExists = "";
 
   /**
    * Set false for MsSqlServer to allow multiple nulls for OneToOne mapping.
@@ -414,6 +414,9 @@ public class PlatformDdl {
     if (create.isConcurrent()) {
       buffer.append(indexConcurrent);
     }
+    if (create.isNotExistsCheck()) {
+      buffer.append(createIndexIfNotExists);
+    }
     buffer.append(maxConstraintName(create.getIndexName())).append(" on ").append(create.getTableName());
     appendColumns(create.getColumns(), buffer);
     return buffer.toString();

ebean-ddl-generator/src/main/java/io/ebeaninternal/dbmigration/ddlgeneration/platform/PostgresDdl.java

@@ -18,6 +18,7 @@ public class PostgresDdl extends PlatformDdl {
     this.dropTableCascade = " cascade";
     this.columnSetType = "type ";
     this.alterTableIfExists = "if exists ";
+    this.createIndexIfNotExists = "if not exists ";
     this.columnSetNull = "drop not null";
     this.addForeignKeySkipCheck = " not valid";
     this.indexConcurrent = "concurrently ";

ebean-ddl-generator/src/main/java/io/ebeaninternal/dbmigration/ddlgeneration/platform/WriteCreateIndex.java

@@ -12,7 +12,11 @@ class WriteCreateIndex {
   private final boolean unique;
   private final boolean concurrent;
   private final String definition;
+  private final boolean notExistsCheck;
 
+  /**
+   * Create index for foreign key.
+   */
   WriteCreateIndex(String indexName, String tableName, String[] columns, boolean unique) {
     this.indexName = indexName;
     this.tableName = tableName;
@@ -20,8 +24,12 @@ class WriteCreateIndex {
     this.unique = unique;
     this.concurrent = false;
     this.definition = null;
+    this.notExistsCheck = false;
   }
 
+  /**
+   * Create non-foreign key index.
+   */
   public WriteCreateIndex(CreateIndex index) {
     this.indexName = index.getIndexName();
     this.tableName = index.getTableName();
@@ -29,6 +37,7 @@ class WriteCreateIndex {
     this.unique = Boolean.TRUE.equals(index.isUnique());
     this.concurrent = Boolean.TRUE.equals(index.isConcurrent());
     this.definition = index.getDefinition();
+    this.notExistsCheck = true;
   }
 
   public String getIndexName() {
@@ -58,4 +67,8 @@ class WriteCreateIndex {
   public boolean useDefinition() {
     return definition != null && !definition.isEmpty();
   }
+
+  public boolean isNotExistsCheck() {
+    return notExistsCheck;
+  }
 }