The SQLAlchemy of Python tools

Source: Internet
Author: User
Tags sql using

Tool Description: SQLAlchemy is an ORM framework in the Python programming language, built on top of the database API, using relational object mappings for database operations, in short: converting objects to SQL and then executing SQL using the data API and getting execution results.

How to work: manipulate a database by defining a class, a table in a database, a row of data in a class object corresponding to a table, inserting data into a database table by instantiating a class, and getting the value of the corresponding field in the table by using the object. Field name.

Take a specific example to illustrate:

#!/usr/bin/env python# -*- coding:utf-8 -*-from sqlalchemy.ext.declarative  import declarative_basefrom sqlalchemy import column, integer, string,  Datetimefrom sqlalchemy.orm import sessionmakerfrom sqlalchemy import create_ engine#  configuration of the MySQL database connection information in the form of a dictionary mysql_dic = {    ' mysql_user ': ' Test ',     ' mysql_pass ': ' 1234 ',    ' mysql_ip ': ' ',    ' mysql_port ': 3306,     ' mysql_db ': ' Test ',}class connect (object):           #  create a class that specifically connects to the database    base = declarative_base ()      #  base class for creating objects    def __init__ (self):       mysql_str  =  "mysql+mysqldb://{mysql_user}:{mysql_pass}@{mysql_ip}:{mysql_port}/{mysql_db}"      #  command line to connect to a database       mysql_con = mysql_str.format (**mysql_dic)                   #  formatting Commands        self.engine = create_engine (mysql_con, max_overflow=5)     #   Initializing database connection       session = sessionmaker (bind=self.engine)                   #  Create a session to manipulate the database       self.session = session ()    def  Create_table (self):       "Look for all subclasses of base, generate corresponding data table information in the database according to the structure of the subclass"        connect.base.metadata.create_all (Self.engine) class server (Connect.Base):     #  define a class (actually a database table) inherit base base class    __tablename__ =  ' server '      #  table names, all of the following fields are table fields    id = column (integer,autoincrement=1,primary_key=true)    date =  Column (DATETIME)    user = column (String)    ip = column ( String (())    group = column (string) if __name__ ==  ' __main__ ':    c = connect ()     #  connect the database and create a session between the program and the database     C.create_table ()  #  create a defined server table           #  Add Data     s = server (user= ' test ', ip= ' ', group= ' monitor ')  #  Instantiate a Class object     c.session.add (s)  #  add a row of data (a class object) to the table through session sessions          # c.session.add_all ([    #      server (user= ' test ', ip= ' ', group= ' monitor '),    #      server (user= ' test ', ip=' ', group= ' monitor '),     # ])     #  add more than one data at a time         c.session.commit ()     #  submit               #  Delete data (delete data in the server table with IDs greater than 2)      c.session.query (Server). Filter ( > 2). Delete ()      C.session.commit ()         #  Modify the data (the Group field value for modifying data with IDs greater than 2 in the server table is Java)     c.session.query (server). Filter (  > 2). Update ({' Group '  :  ' JAVA '})     c.session.commit ()          #  Querying data (querying all data in the server table for which the user field value is test)     ret =  C.session.query (Server). filter_by (user= ' test '). All ()     for i in ret:         print i.ip    #  gets the value of the IP field in the data that meets the criteria               c.session.close ()      #  Close session

part of the blog content and ideas organized from Wu Jianzi blog .

This article from "A rookie on the Sky" blog, please be sure to keep this source

The SQLAlchemy of Python tools

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