Writing MySQL-Based Programs - MySQL - page 38

#!/usr/bin/python
# connect.py: connect to the MySQL server
import mysql.connector
try :
conn = mysql . connector . connect ( database = "cookbook" ,
host = "localhost" ,
user = "cbuser" ,
password = "cbpass" )
print ( "Connected" )
except :
print ( "Cannot connect to server" )
else :
conn . close ()
print ( "Disconnected" )
To try connect.py , locate it under the api directory of the recipes distribution and run
it from the command line. The program should print two lines indicating that it con‐
nected and disconnected successfully:
% python connect.py
Connected
Disconnected
For background on running Python programs, read “Executing Programs from the
Command Line” on the companion website (see the Preface ).
The import line tells Python to load the mysql.connector module. Then the script
attempts to establish a connection to the MySQL server by calling connect() to obtain
a connection object. Python scripts in this topic conventionally use conn to signify
connection objects.
If the connect() method fails, Connector/Python raises an exception. To handle ex‐
ceptions, put the statements that might fail inside a try statement and use an except
clause that contains the error-handling code. Exceptions that occur at the top level of a
script (that is, outside of any try statement) are caught by the default exception handler,
which prints a stack trace and exits. Recipe 2.2 discusses error handling further.
The else clause contains statements that execute if the try clause produces no excep‐
tion. It's used here to close the successfully opened connection.
Because the connect() call uses named arguments, their order does not matter. If you
omit the host argument from the connect() call, its default value is 127.0.0.1 . To select
no default database, omit the database argument or pass a database value of "" (the
empty string) or None .
Another way to connect is to specify the parameters using a Python dictionary and pass
the dictionary to connect() :