Some quick syntax reminders for common tasks using DB-API2 modules.
| task | postgresql | sqlite | MySQL | Oracle | ODBC | oursql |
|---|---|---|---|---|---|---|
| create database | createdb mydb | created automatically when opened with sqlite3 | created with Oracle XE install | |||
| command-line tool | psql -d mydb | sqlite3 mydb.sqlite | mysql testdb | sqlplus scott/tiger | ||
| GUI tool | pgadmin3 | mysql-admin | sqldeveloper | |||
| install module | easy_install psycopg2 | included in Python 2.5 standard library | easy_install mysql-python or apt-get install python-mysqldb | easy_install cx_oracle (but see note) | ||
| import | from psycopg2 import * | from sqlite3 import * | from MySQLdb import * | from cx_Oracle import * | ||
| connect | conn = connect("dbname='testdb' user='me' host='localhost' password='mypassword'”) | conn = connect('mydb.sqlite') or conn=connect(':memory:') | conn = connect (host="localhost", db="testdb", user="me", passwd="mypassword") | conn=connect('scott/tiger@xe') | conn = odbc.odbc('DBALIAS') or odbc.odbc('DBALIAS/USERNAME/PASSWORD') | |
| get cursor | curs = conn.cursor() | curs = conn.cursor() | curs = conn.cursor() | curs = conn.cursor() | ||
| execute SELECT | curs.execute('SELECT * FROM tbl') | curs.execute('SELECT * FROM tbl') | curs.execute('SELECT * FROM tbl') | curs.execute('SELECT * FROM tbl') | ||
| fetch | curs.fetchone(); curs.fetchall(); curs.fetchmany() | curs.fetchone(); curs.fetchall(); curs.fetchmany() | curs.fetchone(); curs.fetchall(); curs.fetchmany() | curs.fetchone(); curs.fetchall(); curs.fetchmany(); for r in curs | ||
| use bind variables | curs.execute('SELECT * FROM tbl WHERE col = %(varnm)s', {'varnm':22}) | curs.execute('SELECT * FROM tbl WHERE col = ?', [22]) | curs.execute('SELECT * FROM tbl WHERE col = %s', [22]) | curs.execute('SELECT * FROM tbl WHERE col = :varnm', {'varnm':22}) | curs.execute('SELECT * FROM tbl WHERE col = ?', (22,)) | |
| commit | conn.commit() (required) | conn.commit() (required) | conn.commit() (required) | conn.commit() (required) |
See also DbApiModuleComparison, DatabaseProgramming