From 8d2c9ae434a9026e9a198120c9a7b6faf0346cd7 Mon Sep 17 00:00:00 2001 From: Mike Bayer Date: Sun, 29 Apr 2007 20:08:55 +0000 Subject: - mysql uses "DESCRIBE [].", catching exceptions if table doesnt exist, in order to determine if a table exists. this supports unicode table names as well as schema names. tested with MySQL5 but should work with 4.1 series as well. (#557) --- lib/sqlalchemy/databases/mysql.py | 23 ++++++++++++++++++----- 1 file changed, 18 insertions(+), 5 deletions(-) (limited to 'lib/sqlalchemy/databases/mysql.py') diff --git a/lib/sqlalchemy/databases/mysql.py b/lib/sqlalchemy/databases/mysql.py index c33b515b5..0903befe9 100644 --- a/lib/sqlalchemy/databases/mysql.py +++ b/lib/sqlalchemy/databases/mysql.py @@ -364,11 +364,24 @@ class MySQLDialect(ansisql.ANSIDialect): def has_table(self, connection, table_name, schema=None): # TODO: this does not work for table names that contain multibyte characters. - # i have tried dozens of approaches here with no luck. statements like - # DESCRIBE and SHOW CREATE TABLE work better, but they raise an error when - # the table does not exist. - cursor = connection.execute("show table status like %s", [table_name]) - return bool( not not cursor.rowcount ) + + # http://dev.mysql.com/doc/refman/5.0/en/error-messages-server.html + + # Error: 1146 SQLSTATE: 42S02 (ER_NO_SUCH_TABLE) + # Message: Table '%s.%s' doesn't exist + + # Error: 1046 SQLSTATE: 3D000 (ER_NO_DB_ERROR) + # Message: No database selected + + try: + name = schema and ("%s.%s" % (schema, table_name)) or table_name + connection.execute("DESCRIBE `%s`" % name) + return True + except exceptions.SQLError, e: + if e.orig.args[0] in (1146, 1046): + return False + else: + raise def reflecttable(self, connection, table): # reference: http://dev.mysql.com/doc/refman/5.0/en/name-case-sensitivity.html -- cgit v1.2.1