#699 - DB Migration not generating sql to alter check constraints

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/platform/BaseTableDdl.java

@@ -635,6 +635,13 @@ public class BaseTableDdl implements TableDdl {
       alterColumnAddUniqueOneToOneConstraint(writer, alterColumn);
     }
 
+
+    boolean alterCheckConstraint = hasValue(alterColumn.getCheckConstraint());
+
+    if (alterCheckConstraint) {
+      // drop constraint before altering type etc
+      dropCheckConstraint(writer, alterColumn);
+    }
     boolean alterBaseAttributes = false;
     if (hasValue(alterColumn.getType())) {
       alterColumnType(writer, alterColumn);
@@ -648,10 +655,13 @@ public class BaseTableDdl implements TableDdl {
       alterColumnNotnull(writer, alterColumn);
       alterBaseAttributes = true;
     }
-
     if (alterBaseAttributes) {
       alterColumnBaseAttributes(writer, alterColumn);
     }
+    if (alterCheckConstraint) {
+      // add constraint last (after potential type change)
+      addCheckConstraint(writer, alterColumn);
+    }
   }
 
   /**
@@ -705,6 +715,22 @@ public class BaseTableDdl implements TableDdl {
     }
   }
 
+  protected void dropCheckConstraint(DdlWrite writer, AlterColumn alter) throws IOException {
+
+    String ddl = platformDdl.alterTableDropConstraint(alter.getTableName(), alter.getCheckConstraintName());
+    if (hasValue(ddl)) {
+      writer.apply().append(ddl).endOfStatement();
+    }
+  }
+
+  protected void addCheckConstraint(DdlWrite writer, AlterColumn alter) throws IOException {
+
+    String ddl = platformDdl.alterTableAddCheckConstraint(alter.getTableName(), alter.getCheckConstraintName(), alter.getCheckConstraint());
+    if (hasValue(ddl)) {
+      writer.apply().append(ddl).endOfStatement();
+    }
+  }
+
   protected void alterColumnNotnull(DdlWrite writer, AlterColumn alter) throws IOException {
 
     String ddl = platformDdl.alterColumnNotnull(alter.getTableName(), alter.getColumnName(), alter.isNotnull());

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/platform/MySqlDdl.java

@@ -38,8 +38,13 @@ public class MySqlDdl extends PlatformDdl {
   }
 
   @Override
-  public String alterColumnType(String tableName, String columnName, String type) {
+  public String alterTableDropConstraint(String tableName, String constraintName) {
+    // drop constraint not supported
+    return null;
+  }
 
+  @Override
+  public String alterColumnType(String tableName, String columnName, String type) {
     // can't alter itself - done in alterColumnBaseAttributes()
     return null;
   }

src/main/java/com/avaje/ebean/dbmigration/ddlgeneration/platform/PlatformDdl.java

@@ -67,8 +67,12 @@ public class PlatformDdl {
 
   protected String alterColumn = "alter column";
 
+  protected String dropConstraint = "drop constraint";
+
   protected String dropUniqueConstraint = "drop constraint";
 
+  protected String addConstraint = "add constraint";
+
   protected String columnSetType = "";
 
   protected String columnSetDefault = "set default";
@@ -327,12 +331,19 @@ public class PlatformDdl {
   }
 
   /**
-   * Drop a unique constraint from the table.
+   * Drop a unique constraint from the table (Sometimes this is an index).
    */
   public String alterTableDropUniqueConstraint(String tableName, String uniqueConstraintName) {
     return "alter table " + tableName + " " + dropUniqueConstraint + " " + uniqueConstraintName;
   }
 
+  /**
+   * Drop a unique constraint from the table.
+   */
+  public String alterTableDropConstraint(String tableName, String constraintName) {
+    return "alter table " + tableName + " " + dropConstraint + " " + constraintName;
+  }
+
   /**
    * Add a unique constraint to the table.
    * <p>
@@ -377,6 +388,14 @@ public class PlatformDdl {
     return "alter table " + tableName + " " + alterColumn + " " + columnName + " " + suffix;
   }
 
+  /**
+   * Alter table adding the check constraint.
+   */
+  public String alterTableAddCheckConstraint(String tableName, String checkConstraintName, String checkConstraint) {
+
+    return "alter table " + tableName + " " + addConstraint + " " + checkConstraintName + " " + checkConstraint;
+  }
+
   /**
    * Return true if the default value is the special DROP DEFAULT value.
    */

src/main/java/com/avaje/ebean/dbmigration/model/MColumn.java

@@ -317,7 +317,7 @@ public class MColumn {
 
     if (different(checkConstraint, newColumn.checkConstraint)) {
       AlterColumn alter = getAlterColumn(tableName, tableWithHistory);
-      if (hasValue(checkConstraint)) {
+      if (hasValue(checkConstraint) && !hasValue(newColumn.checkConstraint)) {
         alter.setDropCheckConstraint(checkConstraintName);
       }
       if (hasValue(newColumn.checkConstraint)) {

src/main/java/com/avaje/ebean/dbmigration/runner/MigrationMetaRow.java

@@ -49,7 +49,6 @@ class MigrationMetaRow {
     version = row.getString("mversion");
     comment = row.getString("mcomment");
     checksum = row.getInteger("mchecksum");
-    runOn = row.getTimestamp("run_on");
     runBy = row.getString("run_by");
     runTime = row.getLong("run_time");
   }

src/main/java/com/avaje/ebean/dbmigration/runner/MigrationTable.java

@@ -142,7 +142,11 @@ public class MigrationTable {
    * Return true if the table exists.
    */
   private boolean tableExists(Connection connection) throws SQLException {
-    return databasePlatform.tableExists(connection, catalog, schema, table);
+    boolean exists = databasePlatform.tableExists(connection, catalog, schema, table);
+    if (!exists) {
+      exists = databasePlatform.tableExists(connection, catalog, schema, table.toUpperCase());
+    }
+    return exists;
   }
 
   /**