protected override void Generate(
            AlterColumnOperation operation,
            IModel model,
            MigrationCommandListBuilder builder)
        {
            Check.NotNull(operation, nameof(operation));
            Check.NotNull(builder, nameof(builder));

            DropDefaultConstraint(operation.Schema, operation.Table, operation.Name, builder);

            builder
                .Append("ALTER TABLE ")
                .Append(SqlGenerationHelper.DelimitIdentifier(operation.Table, operation.Schema))
                .Append(" ALTER COLUMN ");

            ColumnDefinition(
                operation.Schema,
                operation.Table,
                operation.Name,
                operation.ClrType,
                operation.ColumnType,
                operation.IsUnicode,
                operation.MaxLength,
                operation.IsRowVersion,
                operation.IsNullable,
                /*defaultValue:*/ null,
                /*defaultValueSql:*/ null,
                operation.ComputedColumnSql,
                /*identity:*/ false,
                operation,
                model,
                builder);

            builder.AppendLine(SqlGenerationHelper.StatementTerminator);

            if ((operation.DefaultValue != null)
                || (operation.DefaultValueSql != null))
            {
                builder
                    .Append("ALTER TABLE ")
                    .Append(SqlGenerationHelper.DelimitIdentifier(operation.Table, operation.Schema))
                    .Append(" ADD");
                DefaultValue(operation.DefaultValue, operation.DefaultValueSql, builder);
                builder
                    .Append(" FOR ")
                    .Append(SqlGenerationHelper.DelimitIdentifier(operation.Name))
                    .AppendLine(SqlGenerationHelper.StatementTerminator);
            }

            EndStatement(builder);
        }
 protected override void Generate(AlterColumnOperation operation, IModel model, RelationalCommandListBuilder builder)
 {
 }
        protected override void Generate(AlterColumnOperation operation, IModel model, MigrationCommandListBuilder builder)
        {
            Check.NotNull(operation, nameof(operation));
            Check.NotNull(builder, nameof(builder));

            // TODO: There is probably duplication here with other methods. See ColumnDefinition.

            //TODO: this should provide feature parity with the EF6 provider, check if there's anything missing for EF7

            var type = operation.ColumnType;
            if (operation.ColumnType == null)
            {
                var property = FindProperty(model, operation.Schema, operation.Table, operation.Name);
                type = property != null
                    ? TypeMapper.GetMapping(property).StoreType
                    : TypeMapper.GetMapping(operation.ClrType).StoreType;
            }

            var serial = operation.FindAnnotation(MyCatAnnotationNames.Prefix + MyCatAnnotationNames.Serial);
            var isSerial = serial != null && (bool)serial.Value;

            var identifier = SqlGenerationHelper.DelimitIdentifier(operation.Table, operation.Schema);
            var alterBase = $"ALTER TABLE {identifier} MODIFY COLUMN {SqlGenerationHelper.DelimitIdentifier(operation.Name)}";

            // TYPE
            builder.Append(alterBase)
                .Append(" ")
                .Append(type)
                .Append(operation.IsNullable ? " NULL" : " NOT NULL")
                .AppendLine(SqlGenerationHelper.StatementTerminator);

            alterBase = $"ALTER TABLE {identifier} ALTER COLUMN {SqlGenerationHelper.DelimitIdentifier(operation.Name)}";

            builder.Append(alterBase);

            if (operation.DefaultValue != null)
            {
                builder.Append(" SET DEFAULT ")
                    .Append(SqlGenerationHelper.GenerateLiteral((dynamic)operation.DefaultValue))
                    .AppendLine(SqlGenerationHelper.BatchTerminator);
            }
            else if (!string.IsNullOrWhiteSpace(operation.DefaultValueSql))
            {
                builder.Append(" SET DEFAULT ")
                    .Append(operation.DefaultValueSql)
                    .AppendLine(SqlGenerationHelper.BatchTerminator);
            }
            else if (isSerial)
            {
                builder.Append(" SET DEFAULT ");

                switch (type)
                {
                    case "smallint":
                    case "int":
                    case "bigint":
                    case "real":
                    case "double precision":
                    case "numeric":
                        //TODO: need function CREATE SEQUENCE IF NOT EXISTS and set to it...
                        //Until this is resolved changing IsIdentity from false to true
                        //on types int2, int4 and int8 won't switch to type serial2, serial4 and serial8
                        throw new NotImplementedException("Not supporting creating sequence for integer types");
                    case "char(38)":
                    case "uuid":
                    case "uniqueidentifier":
                        builder.Append("UUID()");
                        break;
                    default:
                        throw new NotImplementedException($"Not supporting creating IsIdentity for {type}");

                }
            }
            else
            {
                builder.Append(" DROP DEFAULT ");
            }
        }
 protected override void Generate(AlterColumnOperation operation, IModel model, MigrationCommandListBuilder builder)
 {
     throw new NotSupportedException(SqliteStrings.InvalidMigrationOperation(operation.GetType().Name));
 }