Python-MySQL CRUD操作

安装PyMySQL

pip install pymysql

对象类比

访问数据库流程

connection对象

con = pymysql.connect(host = '',
                      port = '',
                      user = '',
                      passwd = '',
                      db = '',
                      charset = 'utf-8' )     

游标对象cursor

one = cur.fetchone()
print(one)
#获取剩余的3条记录
three = cur.fetchmany(3)
print(three)
# 获取剩余所有记录列表
rows = cur.fetchall()
print("表中剩余所有记录:", rows)
print("number of records:", len(rows))

结果如下

(1, 'aaa')
((2, 'bbb'), (3, 'ccc'), (4, 'ddd'))
表中所有记录: ((5, 'eee'), (6, 'fff'))
number of records: 2

事务回滚

try:
    cur.execute();  
    db.commit()
    print("Success")
except Exception as e:
    print(e)
    db.rollback()

execute执行流程

CRUD操作
增加(Create)、读取查询(Retrieve)、更新(Update)和删除(Delete)

import pymysql
conn = pymysql.connect("IP或者域名","mysql账户名","mysql密码","数据库名")
cur = conn.cursor()
#如果表存在,删除表
cur.execute("DROP TABLE IF EXISTS demo")
#建立表 (列名 类型)
cur.execute('CREATE TABLE demo(num int ,str varchar(20));')
#插入
#两种方式均可,但必须用双引号
cur.execute("INSERT INTO demo VALUES(%d, '%s')" % (1,'aaa'))
cur.execute("INSERT INTO demo VALUES(2,'bbb')")
#更新
cur.execute("UPDATE demo SET str ='ccc' where num = 1")
#查询
cur.execute("SELECT * FROM demo")
# 获取所有记录列表
rows = cur.fetchall()
print("表中所有记录:",rows)
print("number of records:",len(rows))
for i in rows:
    print("num=%s,str=%s" % i)
#提交事务,使上述操作生效
conn.commit()
#关闭游标对象
cur.close()
#关闭数据库连接
conn.close()