[SOLVED] Suggested way to run multiple sql statements in python?

Issue

What would be the suggested way to run something like the following in python:

self.cursor.execute('SET FOREIGN_KEY_CHECKS=0; DROP TABLE IF EXISTS %s; SET FOREIGN_KEY_CHECKS=1' % (table_name,))

For example, should this be three separate self.cursor.execute(...) statements? Is there a specific method that should be used other than cursor.execute(...) to do something like this, or what is the suggested practice for doing this? Currently the code I have is as follows:

self.cursor.execute('SET FOREIGN_KEY_CHECKS=0;')
self.cursor.execute('DROP TABLE IF EXISTS %s;' % (table_name,))
self.cursor.execute('SET FOREIGN_KEY_CHECKS=1;')
self.cursor.execute('CREATE TABLE %s select * from mytable;' % (table_name,))

As you can see, everything is run separately…so I’m not sure if this is a good idea or not (or rather — what the best way to do the above is). Perhaps BEGIN...END ?

Solution

I would create a stored procedure:

DROP PROCEDURE IF EXISTS CopyTable;
DELIMITER $$
CREATE PROCEDURE CopyTable(IN _mytable VARCHAR(64), _table_name VARCHAR(64))
BEGIN
    SET FOREIGN_KEY_CHECKS=0;
    SET @stmt = CONCAT('DROP TABLE IF EXISTS ',_table_name);
    PREPARE stmt1 FROM @stmt;
    EXECUTE stmt1;
    SET FOREIGN_KEY_CHECKS=1;
    SET @stmt = CONCAT('CREATE TABLE ',_table_name,' as select * from ', _mytable);
    PREPARE stmt1 FROM @stmt;
    EXECUTE stmt1;
    DEALLOCATE PREPARE stmt1;
END$$
DELIMITER ;

and then just run:

args = ['mytable', 'table_name']
cursor.callproc('CopyTable', args)

keeping it simple and modular. Of course you should do some kind of error checking and you could even have the stored procedure return a code to indicate success or failure.

Answered By – Dan M

Answer Checked By – Candace Johnson (BugsFixing Volunteer)