HHH-7797 Block "unique" syntax on a column if a constraint can/will be

used

hibernate-core/src/main/java/org/hibernate/dialect/Dialect.java

@@ -1977,6 +1977,11 @@ public abstract class Dialect implements ConversionContext {
 		return true;
 	}
 
+	/**
+	 * Does this dialect support columns that are both unique and not null.
+	 * 
+	 * @return True if supported, false otherwise.
+	 */
 	public boolean supportsNotNullUnique() {
 		return true;
 	}

hibernate-core/src/main/java/org/hibernate/mapping/Table.java

@@ -423,10 +423,13 @@ public class Table implements RelationalModel, Serializable {
 					alter.append( " not null" );
 				}
 
-				boolean useUniqueConstraint = column.isUnique() &&
+				// If the column is 1.) unique, 2.) the dialect supports the
-						dialect.supportsUnique() &&
+				// unique syntax, 3.) the column is nullable or supports
-						( column.isNullable() || dialect.supportsNotNullUnique() );
+				// "not null unique", and 4.) a constraint will not be created
-				if ( useUniqueConstraint ) {
+				if ( column.isUnique() && dialect.supportsUnique()
+						&& ( column.isNullable()
+								|| dialect.supportsNotNullUnique() )
+						&& !dialect.supportsUniqueConstraintInCreateAlterTable() ) {
 					alter.append( " unique" );
 				}
 
@@ -524,17 +527,21 @@ public class Table implements RelationalModel, Serializable {
 				}
 
 			}
-
+			
-			boolean useUniqueConstraint = col.isUnique() &&
+			// If the column is 1.) unique and nullable or 2.) unique,
-					( col.isNullable() || dialect.supportsNotNullUnique() );
+			// not null, and the dialect supports unique not null			
-			if ( useUniqueConstraint ) {
+			if ( col.isUnique()
-				if ( dialect.supportsUnique() ) {
+					&& ( col.isNullable()
-					buf.append( " unique" );
+							|| dialect.supportsNotNullUnique() ) ) {
-				}
+				if ( dialect.supportsUniqueConstraintInCreateAlterTable() ) {
-				else {
+					// If the constraint is supported, do not add to the column syntax.
 					UniqueKey uk = getOrCreateUniqueKey( col.getQuotedName( dialect ) + '_' );
 					uk.addColumn( col );
 				}
+				else if ( dialect.supportsUnique() ) {
+					// Otherwise, add to the column syntax if supported.
+					buf.append( " unique" );
+				}
 			}
 
 			if ( col.hasCheckConstraint() && dialect.supportsColumnCheck() ) {

hibernate-core/src/main/java/org/hibernate/mapping/UniqueKey.java

@@ -35,23 +35,21 @@ import org.hibernate.engine.spi.Mapping;
 public class UniqueKey extends Constraint {
 
 	public String sqlConstraintString(Dialect dialect) {
+		// TODO: This may not be necessary, but not all callers currently
+		// check it on their own.  Go through their logic.
+		if ( !isGenerated( dialect ) ) return null;
+		
 		StringBuilder buf = new StringBuilder( "unique (" );
-		boolean hadNullableColumn = false;
 		Iterator iter = getColumnIterator();
 		while ( iter.hasNext() ) {
 			Column column = (Column) iter.next();
-			if ( !hadNullableColumn && column.isNullable() ) {
-				hadNullableColumn = true;
-			}
 			buf.append( column.getQuotedName( dialect ) );
 			if ( iter.hasNext() ) {
 				buf.append( ", " );
 			}
 		}
-		//do not add unique constraint on DB not supporting unique and nullable columns
+		
-		return !hadNullableColumn || dialect.supportsNotNullUnique() ?
+		return buf.append( ')' ).toString();
-				buf.append( ')' ).toString() :
-				null;
 	}
 
 	@Override
@@ -60,18 +58,19 @@ public class UniqueKey extends Constraint {
 			String constraintName,
 			String defaultCatalog,
 			String defaultSchema) {
+		// TODO: This may not be necessary, but not all callers currently
+		// check it on their own.  Go through their logic.
+		if ( !isGenerated( dialect ) ) return null;
+		
 		StringBuilder buf = new StringBuilder(
-				dialect.getAddUniqueConstraintString( constraintName )
+		dialect.getAddUniqueConstraintString( constraintName ) ).append( '(' );
-		).append( '(' );
 		Iterator iter = getColumnIterator();
-		boolean nullable = false;
 		while ( iter.hasNext() ) {
 			Column column = (Column) iter.next();
-			if ( !nullable && column.isNullable() ) nullable = true;
 			buf.append( column.getQuotedName( dialect ) );
 			if ( iter.hasNext() ) buf.append( ", " );
 		}
-		return !nullable || dialect.supportsNotNullUnique() ? buf.append( ')' ).toString() : null;
+		return buf.append( ')' ).toString();
 	}
 
 	@Override
@@ -97,12 +96,13 @@ public class UniqueKey extends Constraint {
 
 	@Override
     public boolean isGenerated(Dialect dialect) {
+		if ( !dialect.supportsUniqueConstraintInCreateAlterTable() ) return false;
 		if ( dialect.supportsNotNullUnique() ) return true;
+		
 		Iterator iter = getColumnIterator();
 		while ( iter.hasNext() ) {
-			if ( ( (Column) iter.next() ).isNullable() ) {
+			// Dialect does not support "not null unique" and this column is not null.
-				return false;
+			if ( ! ( (Column) iter.next() ).isNullable() ) return false;
-			}
 		}
 		return true;
 	}

hibernate-core/src/main/java/org/hibernate/metamodel/relational/Table.java

@@ -199,16 +199,20 @@ public class Table extends AbstractTableSpecification implements Exportable {
 
 			}
 
-			boolean useUniqueConstraint = col.isUnique() &&
+			// If the column is 1.) unique and nullable or 2.) unique,
-					( col.isNullable() || dialect.supportsNotNullUnique() );
+			// not null, and the dialect supports unique not null			
-			if ( useUniqueConstraint ) {
+			if ( col.isUnique()
-				if ( dialect.supportsUnique() ) {
+					&& ( col.isNullable()
-					buf.append( " unique" );
+							|| dialect.supportsNotNullUnique() ) ) {
-				}
+				if ( dialect.supportsUniqueConstraintInCreateAlterTable() ) {
-				else {
+					// If the constraint is supported, do not add to the column syntax.
 					UniqueKey uk = getOrCreateUniqueKey( col.getColumnName().encloseInQuotesIfQuoted( dialect ) + '_' );
 					uk.addColumn( col );
 				}
+				else if ( dialect.supportsUnique() ) {
+					// Otherwise, add to the column syntax if supported.
+					buf.append( " unique" );
+				}
 			}
 
 			if ( col.getCheckCondition() != null && dialect.supportsColumnCheck() ) {

hibernate-core/src/main/java/org/hibernate/metamodel/relational/UniqueKey.java

@@ -48,21 +48,22 @@ public class UniqueKey extends AbstractConstraint implements Constraint {
 
 	@Override
     public boolean isCreationVetoed(Dialect dialect) {
-		if ( dialect.supportsNotNullUnique() ) {
+		if ( !dialect.supportsUniqueConstraintInCreateAlterTable() ) return true;
-			return false;
+		if ( dialect.supportsNotNullUnique() ) return false;
-		}
+		
-
 		for ( Column column : getColumns() ) {
-			if ( column.isNullable() ) {
+			// Dialect does not support "not null unique" and this column is not null.
-				return true;
+			if ( ! column.isNullable() ) return true;
-			}
 		}
 		return false;
 	}
 
 	public String sqlConstraintStringInCreateTable(Dialect dialect) {
+		// TODO: This may not be necessary, but not all callers currently
+		// check it on their own.  Go through their logic.
+		if ( isCreationVetoed( dialect ) ) return null;
+				
 		StringBuilder buf = new StringBuilder( "unique (" );
-		boolean hadNullableColumn = false;
 		boolean first = true;
 		for ( Column column : getColumns() ) {
 			if ( first ) {
@@ -71,23 +72,19 @@ public class UniqueKey extends AbstractConstraint implements Constraint {
 			else {
 				buf.append( ", " );
 			}
-			if ( !hadNullableColumn && column.isNullable() ) {
-				hadNullableColumn = true;
-			}
 			buf.append( column.getColumnName().encloseInQuotesIfQuoted( dialect ) );
 		}
-		//do not add unique constraint on DB not supporting unique and nullable columns
+		return buf.append( ')' ).toString();
-		return !hadNullableColumn || dialect.supportsNotNullUnique() ?
-				buf.append( ')' ).toString() :
-				null;
 	}
 
 	@Override
     public String sqlConstraintStringInAlterTable(Dialect dialect) {
+		// TODO: This may not be necessary, but not all callers currently
+		// check it on their own.  Go through their logic.
+		if ( isCreationVetoed( dialect ) ) return null;
+				
 		StringBuilder buf = new StringBuilder(
-				dialect.getAddUniqueConstraintString( getName() )
+		dialect.getAddUniqueConstraintString( getName() ) ).append( '(' );
-		).append( '(' );
-		boolean nullable = false;
 		boolean first = true;
 		for ( Column column : getColumns() ) {
 			if ( first ) {
@@ -96,11 +93,8 @@ public class UniqueKey extends AbstractConstraint implements Constraint {
 			else {
 				buf.append( ", " );
 			}
-			if ( !nullable && column.isNullable() ) {
-				nullable = true;
-			}
 			buf.append( column.getColumnName().encloseInQuotesIfQuoted( dialect ) );
 		}
-		return !nullable || dialect.supportsNotNullUnique() ? buf.append( ')' ).toString() : null;
+		return buf.append( ')' ).toString();
 	}
 }