protected override IEnumerable <Command> OnCreate(IMetadata sourceMetadata, IMetadata targetMetadata, IComparerContext context)
{
var command = new Command();
command.Append($"ALTER TABLE {RelationName.AsSqlIndentifier()}");
if (!SqlHelper.IsImplicitIntegrityConstraintName(ConstraintName))
{
command.Append($" ADD CONSTRAINT {ConstraintName.AsSqlIndentifier()}");
}
else
{
command.Append(" ADD");
}
switch (RelationConstraintType)
{
case RelationConstraintType.Check:
command.Append($" {Triggers[0].TriggerSource}");
break;
case RelationConstraintType.NotNull:
break;
case RelationConstraintType.ForeignKey:
case RelationConstraintType.PrimaryKey:
case RelationConstraintType.Unique:
{
var fields =
Index
.Segments
.OrderBy(s => s.FieldPosition)
.Select(s => s.FieldName);
command.Append($" {RelationConstraintType.ToDescription()} ({string.Join(", ", fields)})");
if (RelationConstraintType == RelationConstraintType.ForeignKey)
{
var referenceConstraint = sourceMetadata.MetadataConstraints.ReferenceConstraintsByName[ConstraintName];
var referenceRelationConstraint = referenceConstraint.RelationConstraintUq;
var primaryKeyFields =
referenceRelationConstraint
.Index
.Segments
.OrderBy(s => s.FieldPosition)
.Select(s => s.FieldName);
command
.AppendLine()
.Append($" REFERENCES {referenceRelationConstraint.RelationName} ({string.Join(", ", primaryKeyFields)})");
if (referenceConstraint.UpdateRule != ConstraintRule.Restrict)
{
command
.AppendLine()
.Append($" ON UPDATE {referenceConstraint.UpdateRule.ToDescription()}");
}
if (referenceConstraint.DeleteRule != ConstraintRule.Restrict)
{
command
.AppendLine()
.Append($" ON DELETE {referenceConstraint.DeleteRule.ToDescription()}");
}
if (referenceConstraint.UpdateRule != ConstraintRule.Restrict || referenceConstraint.DeleteRule != ConstraintRule.Restrict)
{
command.AppendLine();
}
}
command.Append(AddConstraintUsingIndex(sourceMetadata, targetMetadata, context));
break;
}
default:
throw new ArgumentOutOfRangeException($"Unknown relation constraint type: {RelationConstraintType}.");
}
yield return(command);
}
protected override IEnumerable <Command> OnDrop(IMetadata sourceMetadata, IMetadata targetMetadata, IComparerContext context)
{
yield return(new Command()
.Append($"ALTER TABLE {RelationName.AsSqlIndentifier()} DROP CONSTRAINT {ConstraintName.AsSqlIndentifier()}"));
}
