Python访问MySQL数据库并实现其增删改查功能

概述：

对于访问数据库的操作，我想大家也都有一些了解。不过，因为最近在学习Python，以下就用Python来实现它。其中包括创建数据库和数据表、插入记录、删除记录、修改记录数据、查询数据、删除数据表、删除数据库。还有一点就是我们最好使用一个新定义的类来处理这件事。因为这会使在以后的使用过程中更加的方便（只需要导入即可，避免了重复制造轮子）。
实现功能介绍：

1.封装一个DB类

2.数据库操作：创建数据库和数据表

3.数据库操作：插入记录

4.数据库操作：一次插入多条记录

5.数据库操作：删除记录

6.数据库操作：修改记录数据

7.数据库操作：一次修改多条记录数据

8.数据库操作：查询数据

9.数据库操作：删除数据表

10.数据库操作：删除数据库
数据库类的定义：

heroDB.py

#!/usr/bin/env python

import MySQLdb

DATABASE_NAME = 'hero'

class HeroDB:
# init class and create a database
def __init__(self, name, conn, cur):
self.name = name
self.conn = conn
self.cur = cur
try:
cur.execute('create database if not exists ' + name)
conn.select_db(name)
conn.commit()
except MySQLdb.Error, e:
print "Mysql Error %d: %s" % (e.args[0], e.args[1])

# create a table
def createTable(self, name):
try:
ex = self.cur.execute
if ex('show tables') == 0:
ex('create table ' + name + '(id int, name varchar(20), sex int, age int, info varchar(50))')
self.conn.commit()
except MySQLdb.Error, e:
print "Mysql Error %d: %s" % (e.args[0], e.args[1])

# insert single record
def insert(self, name, value):
try:
self.cur.execute('insert into ' + name + ' values(%s,%s,%s,%s,%s)', value)
except MySQLdb.Error, e:
print "Mysql Error %d: %s" % (e.args[0], e.args[1])

# insert more records
def insertMore(self, name, values):
try:
self.cur.executemany('insert into ' + name + ' values(%s,%s,%s,%s,%s)', values)
except MySQLdb.Error, e:
print "Mysql Error %d: %s" % (e.args[0], e.args[1])

# update single record from table
# name: table name
# values: waiting to update data
def updateSingle(self, name, value):
try:
# self.cur.execute('update ' + name + ' set name=' + str(values[1]) + ', sex=' + str(values[2]) + ', age=' + str(values[3]) + ', info=' + str(values[4]) + ' where id=' + str(values[0]) + ';')
self.cur.execute('update ' + name + ' set name=%s, sex=%s, age=%s, info=%s where id=%s;', value)
except MySQLdb.Error, e:
print "Mysql Error %d: %s" % (e.args[0], e.args[1])

# update some record from table
def update(self, name, values):
try:
self.cur.executemany('update ' + name + ' set name=%s, sex=%s, age=%s, info=%s where id=%s;', values)
except MySQLdb.Error, e:
print "Mysql Error %d: %s" % (e.args[0], e.args[1])

# get record count from db table
def getCount(self, name):
try:
count = self.cur.execute('select * from ' + name)
return count
except MySQLdb.Error, e:
print "Mysql Error %d: %s" % (e.args[0], e.args[1])

# select first record from database
def selectFirst(self, name):
try:
self.cur.execute('select * from ' + name + ';')
result = self.cur.fetchone()
return result
except MySQLdb.Error, e:
print "Mysql Error %d: %s" % (e.args[0], e.args[1])

# select last record from database
def selectLast(self, name):
try:
self.cur.execute('SELECT * FROM ' + name + ' ORDER BY id DESC;')
result = self.cur.fetchone()
return result
except MySQLdb.Error, e:
print "Mysql Error %d: %s" % (e.args[0], e.args[1])

# select next n records from database
def selectNRecord(self, name, n):
try:
self.cur.execute('select * from ' + name + ';')
results = self.cur.fetchmany(n)
return results
except MySQLdb.Error, e:
print "Mysql Error %d: %s" % (e.args[0], e.args[1])

# select all records
def selectAll(self, name):
try:
self.cur.execute('select * from ' + name + ';')
self.cur.scroll(0, mode='absolute') # reset cursor location (mode = absolute | relative)
results = self.cur.fetchall()
return results
except MySQLdb.Error, e:
print "Mysql Error %d: %s" % (e.args[0], e.args[1])

# delete a record
def deleteByID(self, name, id):
try:
self.cur.execute('delete from ' + name + ' where id=%s;', id)
except MySQLdb.Error, e:
print "Mysql Error %d: %s" % (e.args[0], e.args[1])

# delete some record
def deleteSome(self, name):
pass

# drop the table
def dropTable(self, name):
try:
self.cur.execute('drop table ' + name + ';')
except MySQLdb.Error, e:
print "Mysql Error %d: %s" % (e.args[0], e.args[1])

# drop the database
def dropDB(self, name):
try:
self.cur.execute('drop database ' + name + ';')
except MySQLdb.Error, e:
print "Mysql Error %d: %s" % (e.args[0], e.args[1])

def __del__(self):
if self.cur != None:
self.cur.close()
if self.conn != None:
self.conn.close()

使用范例：

testHeroDB.py

#!/usr/bin/env python

import MySQLdb
from heroDB import HeroDB

def main():
conn = MySQLdb.connect(host='localhost', user='root', passwd='260606', db='hero', port=3306, charset='utf8')
cur = conn.cursor()

# ------------------------------------------- create -----------------------------------------------------
hero = HeroDB('hero', conn, cur)
hero.createTable('heros')

# ------------------------------------------- insert -----------------------------------------------------
hero.insert('heros', [3, 'Prophet', 0, 2000, 'The hero who in fairy tale.'])

# ------------------------------------------- select -----------------------------------------------------
print '-' * 60
print 'first record'
result = hero.selectFirst('heros')
print result

print '-' * 60
print 'last record'
result = hero.selectLast('heros')
print result

print '-' * 60
print 'more record'
results = hero.selectNRecord('heros', 3)
for item in results:
print item

print '-' * 60
print 'all record'
results = hero.selectAll('heros')
for item in results:
print item

# ------------------------------------------- update -----------------------------------------------------
hero.updateSingle('heros', ['Zeus', 1, 22000, 'The god.', 2])

values = []
values.append(['SunWukong', 1, 1300, 'The hero who in fairy tale.', 1])
values.append(['Zeus', 1, 50000, 'The king who in The Quartet myth.', 2])
values.append(['Prophet', 1, 20000, 'The hero who in fairy tale.3', 3])
hero.update('heros', values)

# ------------------------------------------- delete -----------------------------------------------------
hero.deleteByID('heros', 1)

hero.dropTable('heros')

hero.dropDB('hero')

if __name__ == '__main__':
main()

注：请不要不假思索地使用他们。如果你想实现某一个功能点，请最好将其他的功能点注释掉，这样才符合单元测试的规范。