Rao Rao - 5 months ago 18
SQL Question

Update database with multiple SQL Statments

I am using mysql connector.Python 1.0.9 downloaded from MySQL site.

I have a sample table here

DROP TABLE IF EXISTS my_table;
CREATE TABLE my_table
(id INT NOT NULL AUTO_INCREMENT UNIQUE,
Shot VARCHAR(4),
sec varchar(5),
lay VARCHAR(15) NOT NULL,
lay_status VARCHAR(15) NOT NULL,
blk VARCHAR(10) NOT NULL,
blk_status VARCHAR(15) NOT NULL,
pri VARCHAR(10) NOT NULL,
pri_status VARCHAR(15) NOT NULL,
ani VARCHAR(10) NOT NULL,
ani_status VARCHAR(15) NOT NULL,
status VARCHAR(5)
);

INSERT INTO my_table VALUES
(1,'SH01','3','1863','yes','1863','yes','P4645','yes','P4557','yes','Over'),
(2,'SH02','2.5','1863','yes','P4645','no','P4557','yes','1863','no','Over'),
(3,'SH03','0.5','P4645','yes','P4557','yes','1863','yes','1863','yes','WIP'),
(4,'SH04','1.25','1863','no','P4645','no','P4557','yes','1863','yes','RTK'),
(5,'SH05','1','1863','yes','1863','yes','P4645','yes','P4557','yes','WIP'),
(6,'SH06','6','P4557','yes','P4645','yes','P4645','yes','P4557','yes','WIP');


i am able to execute a single SQL statment as below.

import mysql.connector

cnx = mysql.connector.connect(user='scott', database='test')
cursor = cnx.cursor()

SQL = '''
update my_table
set
LAY = 'P6682'
, BLK = 'P6682'
, ANI = 'P6682'
where
Shot = 'SH01';
'''

cursor.execute(SQL)


and everything is fine and database gets updated correctly.

now when i am trying to update the database with multiple statements as below

import mysql.connector

cnx = mysql.connector.connect(user='scott', database='test')
cursor = cnx.cursor()

SQL = '''
update my_table
set
LAY = 'P6682'
, BLK = 'P6682'
, ANI = 'P6682'
where
Shot = 'SH01';

update my_table
set
LAY = '1863'
, BLK = '1863'
, ANI = '1863'
where
Shot = 'SH02'
'''

cursor.execute(SQL)
cnx.commit()
cur.close()
cnx.close()
cnx.disconnect()


I get below trackback error

Traceback (most recent call last):
File "Test_Module.py", line 24, in
File "C:\Python26\Lib\site-packages\mysql\connector\cursor.py", line 396, in execute
"Use multi=True when executing multiple statements")
InterfaceError: Use multi=True when executing multiple statements


I update my command as below

cursor.execute(SQL,multi = True)

cnx.commit()
cur.close()
cnx.close()
cnx.disconnect()


Now i dont get any error/Traceback. But the database is not getting updated.

Can any one tell me where am i doing wrong.

Rao Rao
Answer

At-last after a long research on docs and help. I could able to solve the issue. Here i am posting the solution so other can be benefited.

using a for loop at cursur.execute with ,multi=True worked. i dont know why we need to loop through.

for result in cursor.execute(SQL,multi = True):
    pass

without loop just cursor.execute(SQL,multi = True) did not do any changes in the database.

import mysql.connector

cnx = mysql.connector.connect(user='scott', database='test')
cursor = cnx.cursor()

SQL = '''
    update my_table 
    set 
    LAY = 'P6682'
    , BLK = 'P6682'
    , ANI = 'P6682'
    where
    Shot = 'SH01';

    update my_table 
    set 
    LAY = '1863'
    , BLK = '1863'
    , ANI = '1863'
    where
    Shot = 'SH02'
'''

for result in cursor.execute(SQL,multi = True):
    pass

cnx.commit()
cur.close()
cnx.close()
cnx.disconnect()
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