大数据:Python操作MySQL

标签:大数据数据数据库

访客:14488  发表于:2017-05-26 09:18:57

配置

win_64

Ubuntu14.04

Python3.x

pip安装pymysql模块

直接使用pip安装 pip install pymysql

win64上直接在cmd中执行

连接本地数据库

使用模块 pymysql 连接数据库

本地数据库相关配置请参阅: http://rustfisher.github.io/2017/02/25/backend/MySQL_install/

#!/usr/bin/python

# coding=utf-8

import pymysql

# 连接本地数据库

conn = pymysql.connect(host='localhost', port=3306, user='root', passwd='a123', db='samp_db1', charset='utf8')

cursor = conn.cursor()

cursor.execute('select * from bigstu')

for row in cursor.fetchall():

print(row)

# 查

cursor.execute('select id, name from bigstu where age > 22')

for res in cursor.fetchall():

print(str(res[0]) + ", " + res[1])

cursor.close()

print('-- end --')

输出:

(1, '张三', '男', 24, datetime.date(2017, 3, 29), '13666665555')

(6, '小刚', '男', 23, datetime.date(2017, 3, 11), '778899888')

(8, '小霞', '女', 20, datetime.date(2017, 3, 13), '13712345678')

(12, '小智', '男', 21, datetime.date(2017, 3, 7), '13787654321')

1, 张三

6, 小刚

-- end --

可以直接执行sql语句。获得的结果是元组。

插入数据

插入一条数据,接上面的代码

insertSql = "insert into bigstu (name, sex, age, mobile) values ('%s','%s',%d,'%s') "

xiuji = ('秀吉', '男', 15, '13400001111')

cursor.execute(insertSql % xiuji)

conn.commit() # 别忘了提交

添加列

在mobile后面添加一列cash

addCo = "alter table bigstu add cash int after mobile"

cursor.execute(addCo)

如果要设置默认值

addCo = "alter table bigstu add cash int default 0 after mobile"

cursor.execute(addCo)

删除数据

删除 name=秀吉 的数据

deleteSql = "delete from bigstu where name = '%s'"

cursor.execute(deleteSql % '秀吉')

删除列

删除cash列

dropCo = "alter table bigstu drop cash"

cursor.execute(dropCo)

修改数据

更新符合条件的数据

updateSql = "update bigstu set sex = '%s' where name = '%s'"

updateXiuji = ('秀吉', '秀吉') # 秀吉的性别是秀吉

cursor.execute(updateSql % updateXiuji)

conn.commit()

事物处理

给某个记录的cash增加

table = "bigstu"

addCash = "update " + table + " set cash = cash + '%d' where name = '%s'"

lucky = (1000, "秀吉")

try:

cursor.execute(addCash % lucky)

except Exception as e:

conn.rollback()

print("加钱失败了")

else:

conn.commit()

直接执行SQL语句,十分方便

代码片段

给数据库添加列

从json中读取需要添加的列名,获取当前2个表中所有的列名

整理得出需要插入的列名,然后将列插入到相应的表中

import pymysql

import json

import os

import secureUtils

mapping_keys = json.load(open("key_mapping_db.json", "r"))

db_keys = [] # json中所有的key

for k in mapping_keys.values():

db_keys.append(k)

conn = pymysql.connect(host='localhost', port=3306, user='root',

passwd='*****', db='db_name', charset='utf8')

cursor = conn.cursor()

table_main = "table_main"

main_table_keys = [] # 主表的列名

cursor.execute("show columns from " + table_main)

for row in cursor.fetchall():

main_table_keys.append(row[0])

staff_table_keys = []

cursor.execute("show columns from table_second")

for row in cursor.fetchall():

staff_table_keys.append(row[0])

need_to_insert_keys = []

for k in db_keys:

if k not in staff_table_keys and k not in main_table_keys and k not in need_to_insert_keys:

need_to_insert_keys.append(k)

print("need to insert " + str(len(need_to_insert_keys)))

print(need_to_insert_keys)

for kn in need_to_insert_keys:

print("add key to db " + kn)

cursor.execute("alter table staff_table add " + kn +" text")

conn.close()

将字段字符改变

这里将main_table_keys中的所有字段改为utf8

# change column character set to utf8

for co in main_table_keys:

change_sql = "alter table " + table_main + " modify " + co + " text character set utf8"

print(change_sql)

cursor.execute(change_sql)

来源:36大数据

评论(0)

您可以在评论框内@您的好友一起参与讨论!

<--script type="text/javascript">BAIDU_CLB_fillSlot("927898");