base.py 文件源码

def get_column_specification(self, column, **kwargs):
        colspec = self.preparer.format_column(column) + " " + \
            self.dialect.type_compiler.process(
                column.type, type_expression=column)

        if column.table is None:
            raise exc.CompileError(
                "The Sybase dialect requires Table-bound "
                "columns in order to generate DDL")
        seq_col = column.table._autoincrement_column

        # install a IDENTITY Sequence if we have an implicit IDENTITY column
        if seq_col is column:
            sequence = isinstance(column.default, sa_schema.Sequence) \
                and column.default
            if sequence:
                start, increment = sequence.start or 1, \
                    sequence.increment or 1
            else:
                start, increment = 1, 1
            if (start, increment) == (1, 1):
                colspec += " IDENTITY"
            else:
                # TODO: need correct syntax for this
                colspec += " IDENTITY(%s,%s)" % (start, increment)
        else:
            default = self.get_column_default_string(column)
            if default is not None:
                colspec += " DEFAULT " + default

            if column.nullable is not None:
                if not column.nullable or column.primary_key:
                    colspec += " NOT NULL"
                else:
                    colspec += " NULL"

        return colspec