SQLite - Python
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最近需要用Python写一个简易通讯录，但是对于数据存储很发愁。大家都知道，使用 Python 中的列表和字典进行存储数据是很不靠谱的，所以就想到Python有没有内置的数据库模块。 SQLite3简介SQLite3 可使用 sqlite3 模块与 Python 进行集成。sqlite3 模块是由 Gerhard Haring 编写的。它提供了一个与 PEP 249 描述的 DB-API 2.0 规范兼容的 SQL 接口。您不需要单独安装该模块，因为 Python 2.5.x 以上版本默认自带了该模块。 怎么样，听起来不错吧！那就快来学习使用吧。 连接数据库下面的 Python 代码显示了如何连接到一个现有的数据库。如果数据库不存在，那么它就会被创建，最后将返回一个数据库对象。 #-*- coding:utf-8 -*-
import sqlite3
conn = sqlite3.connect('mysql_person.db')
print "Opened database successfully";
在这里，您也可以把数据库名称复制为特定的名称 :memory:，这样就会在 RAM 中创建一个数据库。现在，让我们来运行上面的程序，在当前目录中创建我们的数据库 mysql_person.db。您可以根据需要改变路径。保存上面代码到 sqlite.py 文件中，并按如下所示执行。如果数据库成功创建，那么会显示下面所示的消息： $chmod +x sqlite.py
$./sqlite.py
Open database successfully
创建表下面的 Python 代码段将用于在先前创建的数据库中创建一个表： #-*- coding:utf-8 -*-
import sqlite3
conn = sqlite3.connect('mysql_person.db')
print "Opened database successfully";
conn.execute('''CREATE TABLE MT (ID INT PRIMARY KEY NOT NULL,NAME TEXT NOT NULL,AGE INT NOT NULL,ADDRESS CHAR(50),SALARY REAL);''')
print "Table created successfully";
conn.close()
上述程序执行时，它会在 test.db 中创建 MT 表，并显示下面所示的消息： Opened database successfully
Table created successfully
INSERT 操作下面的 Python 程序显示了如何在上面创建的 MT 表中创建记录： #-*- coding:utf-8 -*-
import sqlite3
conn = sqlite3.connect('mysql_person.db')
print "Opened database successfully";
conn.execute("INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) VALUES (1,'Paul',32,'California',20000.00 )");
conn.execute("INSERT INTO COMPANY (ID,SALARY) VALUES (2,'Allen',25,'Texas',15000.00 )");
conn.execute("INSERT INTO COMPANY (ID,SALARY) VALUES (3,'Teddy',23,'Norway',SALARY) VALUES (4,'Mark','Rich-Mond ',65000.00 )");
conn.commit()
print "Records created successfully";
conn.close()
上述程序执行时，它会在 MT 表中创建给定记录，并会显示以下两行： Opened database successfully
Records created successfully
SELECT 操作下面的 Python 程序显示了如何从前面创建的 MT 表中获取并显示记录： #-*- coding:utf-8 -*-
import sqlite3
conn = sqlite3.connect('mysql_person.db')
print "Opened database successfully";
cursor = conn.execute("SELECT id,name,address,salary from MT")
for row in cursor:
print "ID = ",row[0]
print "NAME = ",row[1]
print "ADDRESS = ",row[2]
print "SALARY = ",row[3],"n"
print "Operation done successfully";
conn.close()
上述程序执行时，它会产生以下结果： Opened database successfully
ID = 1
NAME = Paul
ADDRESS = California
SALARY = 20000.0
ID = 2
NAME = Allen
ADDRESS = Texas
SALARY = 15000.0
ID = 3
NAME = Teddy
ADDRESS = Norway
SALARY = 20000.0
ID = 4
NAME = Mark
ADDRESS = Rich-Mond
SALARY = 65000.0
Operation done successfully
UPDATE 操作下面的 Python 代码显示了如何使用 UPDATE 语句来更新任何记录，然后从 COMPANY 表中获取并显示更新的记录： #-*- coding:utf-8 -*-
import sqlite3
conn = sqlite3.connect('mysql_person.db')
print "Opened database successfully";
conn.execute("UPDATE COMPANY set SALARY = 25000.00 where ID=1")
conn.commit()
print "Total number of rows updated :",conn.total_changes
cursor = conn.execute("SELECT id,"n"
print "Operation done successfully";
conn.close()
上述程序执行时，它会产生以下结果： Opened database successfully
Total number of rows updated : 1
ID = 1
NAME = Paul
ADDRESS = California
SALARY = 25000.0
ID = 2
NAME = Allen
ADDRESS = Texas
SALARY = 15000.0
ID = 3
NAME = Teddy
ADDRESS = Norway
SALARY = 20000.0
ID = 4
NAME = Mark
ADDRESS = Rich-Mond
SALARY = 65000.0
Operation done successfully
DELETE 操作下面的 Python 代码显示了如何使用 DELETE 语句删除任何记录，然后从 COMPANY 表中获取并显示剩余的记录： #-*- coding:utf-8 -*-
import sqlite3
conn = sqlite3.connect('mysql_person.db')
print "Opened database successfully";
conn.execute("DELETE from COMPANY where ID=2;")
conn.commit()
print "Total number of rows deleted :","n"
print "Operation done successfully";
conn.close()
上述程序执行时，它会产生以下结果： Opened database successfully
Total number of rows deleted : 1
ID = 1
NAME = Paul
ADDRESS = California
SALARY = 20000.0
ID = 3
NAME = Teddy
ADDRESS = Norway
SALARY = 20000.0
ID = 4
NAME = Mark
ADDRESS = Rich-Mond
SALARY = 65000.0
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