Explanation of basic operation examples of SQLite3 in Python
这篇文章主要介绍了Python2.7编程中SQLite3基本操作方法,涉及Python2.7操作sqlite3数据库的增删改查及防注入等相关技巧,需要的朋友可以参考下
本文实例讲述了Python2.7中SQLite3基本操作方法。分享给大家供大家参考,具体如下:
1、基本操作
# -*- coding: utf-8 -*- #!/usr/bin/env python import sqlite3 def mykey(x): return x[3] conn=sqlite3.connect("D:\\demo\\my_db.db") sql = "CREATE TABLE IF NOT EXISTS mytb ( a char , b int , c real, d DATE)" # a char , b int , c real 表示该表有三个字段, # a 是字符串类型, b 是整数类型, c 是实数类型。 conn.execute( sql ) cs = conn.cursor() #cs.execute("DELETE FROM mytb WHERE A='张三' ") cs.execute("DELETE FROM mytb ") #删除所有记录 ''''' cs.execute( "INSERT INTO mytb ( a,b,c,d ) values('Zhang San',25, 120, '2014-03-04')" ) cs.execute( "INSERT INTO mytb ( a,b,c,d ) values( 'Wang Wu',24, 110, '2014-05-01')" ) cs.execute( "INSERT INTO mytb ( a,b,c,d ) values( 'Li Si',23, 130, '2014-04-06')" ) ''' #批量注入,batchdata是一个列表,列表里每一个元素都是一个元组 batchdata=[('Zhang San',25, 120, '2014-03-04'), ( 'Wang Wu',24, 110, '2014-05-01'), ( 'Li Si',23, 130, '2014-04-06')] cs.executemany('INSERT INTO mytb values (?,?,?,?)',batchdata) conn.commit() #将加入的记录保存到磁盘,非常重要! cs.execute("SELECT name, sql FROM sqlite_master WHERE type='table'") recs = cs.fetchall( ) print ( recs ) cs.execute( "SELECT * FROM mytb ")#打开数据表 recs = cs.fetchall()#取出所有记录 print ( "there is ", len(recs)," notes." ) print recs recs.sort(key = mykey) print recs cs.close() conn.close()
2、删除一条记录,使用sql字符串变量可以实现带参数的删除
sql="DELETE FROM my_table WHERE number='" + my_num + "'" cs.execute(sql)
3、查询某一条或多条记录
如果SQLite3查找的数据库记录中含有中文,取出到Python时要对数据进行decode处理。当时我上网查的时候说要用GBK解码,但我自己却解码失败了,换成utf-8解码才成功显示。 另外,如果只查询一条可以用fetchone语句,或者fetchall之后再通过python把它找出来。
sql="SELECT name FROM my_table WHERE number ='" + my_num + "'" cs.execute(sql) the_name=(cs.fetchall())[0][0].decode('utf-8')
4、避免重复注入
有时候我们会有重复的记录,为了避免把相同的记录多次插入到数据库,可以使用如下语句:
sql="INSERT OR REPLACE INTO "+my_table+" values (?,?,?,?,?,?,?) " #假设my_table有7项
5、插入中文记录至SQLite3
Python是unicode编码,但数据库对中文是使用GBK编码,比如stock_name变量含有中文,则需要做unicode(name, "gbk")处理
batch=[(stock_num, unicode(stock_name, "gbk") )] cs.executemany( "INSERT OR REPLACE INTO my_table values (?,?) ",batch)
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