pgmigrate.py 文件源码

def _is_initialized(cursor):
    """
    Check that database is initialized
    """
    cursor.execute('SELECT EXISTS(SELECT 1 FROM '
                   'information_schema.tables '
                   'WHERE table_schema = %s '
                   'AND table_name = %s)',
                   ('public', 'schema_version'))
    table_exists = cursor.fetchone()[0]

    if not table_exists:
        return False

    cursor.execute('SELECT * from public.schema_version limit 1')

    colnames = [desc[0] for desc in cursor.description]

    if colnames != REF_COLUMNS:
        raise MalformedSchema(
            'Table schema_version has unexpected '
            'structure: {struct}'.format(struct='|'.join(colnames)))

    return True