python database interfaces

Database interfaces

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Python database interfaces

Generic Database Interfaces and APIs

• ODBC Supporto pyodbco mxODBC

• ADO Supporto adodbapi

• JDBC Supporto Integrated in Jython

Fall 2012


• Connect to a DatabaseMake a direct connection to a database and create a cursor.

pyodbc

Fall 2012

import pyodbccnxn = pyodbc.connect('DRIVER={SQL Server}; SERVER=localhost; DATABASE=testdb; UID=user; PWD=pass')cursor = cnxn.cursor()


• Selecting Some DataExecute query then fetch results.

Fall 2012

pyodbc

cursor.execute("select user_id, user_name from users")row = cursor.fetchone()print 'name:', row[1] # access by column indexprint 'name:', row.user_name # or access by name

cursor.execute("select user_id, user_name from users")rows = cursor.fetchall()for row in rows: print row.user_id, row.user_name


• Inserting or deletingExecute query then commit changes.

Fall 2012

pyodbc

cursor.execute("insert into products(id, name) values ('pyodbc', 'awesome')")cnxn.commit()

deleted = cursor.execute("delete from products where id <> 'pyodbc'").rowcountcnxn.commit()


• General Purpose Database Systems

• Database Systems for Embedding Into Applications

Fall 2012

Interfaces for Relational Database Systems


General Purpose Database Systems

• Microsoft SQL Server• Oracle• MySQL• IBM DB2• PostgreSQL• Firebird (and Interbase)• Informix• SAP DB (also known as "MaxDB")• …

Fall 2012


• mssqlo MS SQL Server module for Python

• pymssqlo A fast MS SQL server client library for Python directly using C

API instead of ODBC.

Fall 2012

Python database interfaces Fall 2012

• cx_Oracleo Lite Oracle DB Server module for Python

• DCOracle2o Advanced Python DB API 2.0 adapter for Oracle from

Zope company.


• MySQLdbo The most famous library for connecting MySQL

in python.

• PyMySQLo Pure-Python MySQL client library.


MySQLdb

Fall 2012

import MySQLdbconn = mysql.connect(‘localhost’, ‘username’, ‘password’, ‘db name’)cursor = conn.cursor()cursor.execute(“Example query”)cursor.commit() #needed for insert and delete

• Benefits:o Very fast and optimized ( written in C)o Has big communityo Defense SQL injectiono very efficient


• Ibm_dbo Python support for IBM DB2 and IBM Informix

• PyDB2o Pure-Python DB2 interface library.


• Psycopgo The most popular PostgreSQL adapter for the Python

• PyGreSQLo Open-source Python module that interfaces to

a PostgreSQL database


Interfaces for Non-Relational Database Systems

• MetaKit• ZODB• Berkeley DB• Durus• Atop

Fall 2012


Native Python Databases

• Buzhugo buzhug is a fast, portable, pure-Python database engine, using

a pythonic non-SQL syntax for all operations.

• SnakeSQLo SnakeSQL is a pure Python SQL database written to

remove the dependence of the Python Web Modules on 3rd party drivers for non-Python databases.

Fall 2012


Django is a high-level Python Web framework that encourages rapid development and clean, pragmatic

design.


Set database server

DATABASES = { 'default': { 'ENGINE': 'django.db.backends.’ # Add 'postgresql_psycopg2', 'mysql', 'sqlite3' or 'oracle'. 'NAME': 'main_db.db', # Or path to database file if using sqlite3. 'USER': '', 'PASSWORD': '', 'HOST': '', # Set to empty string for localhost. 'PORT': '', # Set to empty string for default. }}

Fall 2012


Using multiple database

• DATABASES = { 'default': {

'NAME': 'app_data', 'ENGINE': 'django.db.backends.postgresql_psycopg2', 'USER': 'postgres_user', 'PASSWORD': 's3krit' },

'users': { 'NAME': 'user_data',

'ENGINE': 'django.db.backends.mysql', 'USER': 'mysql_user', 'PASSWORD': 'priv4te' } }

Fall 2012


Resources

Fall 2012

• Expert Python Programming


Resources

Fall 2012

• wiki.python.org

• www.djangoproject.com


THANK YOU

Fall 2012

python database interfaces

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