protected override IEnumerable<MigrationOperation> Diff(IProperty source, IProperty target)
{
var operations = base.Diff(source, target).ToList();
var sourceValueGenerationStrategy = GetValueGenerationStrategy(source);
var targetValueGenerationStrategy = GetValueGenerationStrategy(target);
var alterColumnOperation = operations.OfType<AlterColumnOperation>().SingleOrDefault();
if (alterColumnOperation == null
&& (source.SqlServer().ComputedExpression != target.SqlServer().ComputedExpression
|| sourceValueGenerationStrategy != targetValueGenerationStrategy))
{
alterColumnOperation = new AlterColumnOperation
{
Schema = source.EntityType.Relational().Schema,
Table = source.EntityType.Relational().Table,
Name = source.Relational().Column,
Type = TypeMapper.GetTypeMapping(target).StoreTypeName,
IsNullable = target.IsNullable,
DefaultValue = target.Relational().DefaultValue,
DefaultExpression = target.Relational().DefaultExpression
};
operations.Add(alterColumnOperation);
}
if (alterColumnOperation != null)
{
if (targetValueGenerationStrategy == SqlServerValueGenerationStrategy.Identity)
{
alterColumnOperation[SqlServerAnnotationNames.Prefix + SqlServerAnnotationNames.ValueGeneration] =
targetValueGenerationStrategy.ToString();
}
if (target.SqlServer().ComputedExpression != null)
{
alterColumnOperation[SqlServerAnnotationNames.Prefix + SqlServerAnnotationNames.ColumnComputedExpression] =
target.SqlServer().ComputedExpression;
alterColumnOperation.IsDestructiveChange |= source.SqlServer().ComputedExpression == null;
}
}
return operations;
}
public override void Generate(AlterColumnOperation operation, IModel model, SqlBatchBuilder builder)
{
throw new NotImplementedException();
}