Executing several SQL queries with MySQLdb

问题

How would you go about executing several SQL statements (script mode) with python?

Trying to do something like this:

import MySQLdb
mysql = MySQLdb.connect(host='host...rds.amazonaws.com', db='dbName', user='userName', passwd='password')
sql = """
insert into rollout.version (`key`, `value`) VALUES ('maxim0', 'was here0');
insert into rollout.version (`key`, `value`) VALUES ('maxim1', 'was here1');
insert into rollout.version (`key`, `value`) VALUES ('maxim2', 'was here1');
"""
mysql.query(sql)

Fails with:

ProgrammingError: (2014, "Commands out of sync; you can't run this command now")

I'm writing an deployment engine that would accept SQL delta changes from several people and apply them to the DB on version deployment.

I've looked into this code http://sujitpal.blogspot.com/2009/02/python-sql-runner.html and implemented __sanitize_sql:

def __sanitize_sql(sql):
    # Initial implementation from http://sujitpal.blogspot.com/2009/02/python-sql-runner.html
    sql_statements = []

    incomment = False
    in_sqlcollect = False

    sql_statement = None
    for sline in sql.splitlines():
        # Remove white space from both sides.
        sline = sline.strip()

        if sline.startswith("--") or len(sline) == 0:
            # SQL Comment line, skip
            continue

        if sline.startswith("/*"):
            # start of SQL comment block
            incomment = True
        if incomment and sline.endswith("*/"):
            # end of SQL comment block
            incomment = False
            continue

        # Collect line which is part of 
        if not incomment:
            if sql_statement is None:
                sql_statement = sline
            else:
                sql_statement += sline

            if not sline.endswith(";"):
                in_sqlcollect = True

            if not in_sqlcollect:
                sql_statements.append(sql_statement)
                sql_statement = None
                in_sqlcollect = False

    if not incomment and not sql_statement is None and len(sql_statement) != 0:
        sql_statements.append(sql_statement)

    return sql_statements

if __name__ == "__main__":
    sql = sql = """update tbl1;
/* This
is my
beautiful 
comment*/
/*this is comment #2*/
some code...;
-- comment
sql code
"""
    print __sanitize_sql(sql)

Don't know if it's the best solution but seems to work for not too complex to parse SQL statements.

The question now how to run this code, I can do something like this dude but it seems ugly, I'm not a python expert (we've been doing python here for just the past 2 weeks) but it seems that abusing cursor this way is hackish and not a good practice.

Ideas / blog posts would be helpful.

Thanks you,
Maxim.

回答1:

Here is how you could use executemany():

import MySQLdb
connection = MySQLdb.connect(host='host...rds.amazonaws.com', db='dbName', user='userName', passwd='password')
cursor = connection.cursor()

my_data_to_insert = [['maxim0', 'was here0'], ['maxim1', 'was here1'], ['maxim2', 'was here1']]
sql = "insert into rollout.version (`key`, `value`) VALUES (%s, %s);"

cursor.executemany(sql, my_data_to_insert)

connection.commit()
connection.close()

回答2:

Call the executemany method on the cursor object. More info here: http://mysql-python.sourceforge.net/MySQLdb.html

来源：https://stackoverflow.com/questions/4615271/executing-several-sql-queries-with-mysqldb

标签

python

sql

batch-processing

sql-scripts