Python 操作 MySQL Python操作使用MySQL数据库的实例代码
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Python 操作 MySQL
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
#!/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。
增
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
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)
改
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)
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