pymysql基本使用
# 导入pymysql模块
import pymysql
# 连接database
conn = pymysql.connect(
host=“你的数据库地址”,
user=“用户名”,password=“密码”,
database=“数据库名”,
charset=“utf8”)
# 得到一个可以执行SQL语句的光标对象
cursor = conn.cursor() # 执行完毕返回的结果集默认以元组显示
# 得到一个可以执行SQL语句并且将结果作为字典返回的游标
#cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)
# 定义要执行的SQL语句
sql = """
CREATE TABLE USER1 (
id INT auto_increment PRIMARY KEY ,
name CHAR(10) NOT NULL UNIQUE,
age TINYINT NOT NULL
)ENGINE=innodb DEFAULT CHARSET=utf8; #注意:charset='utf8' 不能写成utf-8
"""
# 执行SQL语句
cursor.execute(sql)
# 关闭光标对象
cursor.close()
# 关闭数据库连接
conn.close()
插入单条数据
import pymysql
conn =pymysql.connect(
host ='192.168.0.103',
port = 3306,
user = 'root',
password ='123',
database ='xing',
charset ='utf8'
)
cursor =conn.cursor() #获取一个光标
sql ='insert into userinfo (user,pwd) values (%s,%s);'
name = 'wuli'
pwd = '123456789'
cursor.execute(sql, [name, pwd])
conn.commit()
cursor.close()
conn.close()
添加多条数据
import pymysql
conn = pymysql.connect(
host='192.168.0.103',
port=3306,
user='root',
password='123',
database='xing',
charset='utf8'
)
# 获取一个光标
cursor = conn.cursor()
# 定义要执行的sql语句
sql = 'insert into userinfo(user,pwd) values(%s,%s);'
data = [
('july', '147'),
('june', '258'),
('marin', '369')
]
# 拼接并执行sql语句
cursor.executemany(sql, data)
# 涉及写操作要注意提交
conn.commit()
# 关闭连接
cursor.close()
conn.close()
获取最新插入数据 (最后一条)
import pymysql
# 建立连接
conn = pymysql.connect(
host="192.168.0.103",
port=3306,
user="root",
password="123",
database="xing",
charset="utf8"
)
# 获取一个光标
cursor = conn.cursor()
# 定义将要执行的SQL语句
sql = "insert into userinfo (user, pwd) values (%s, %s);"
name = "wuli"
pwd = "123456789"
# 并执行SQL语句
cursor.execute(sql, [name, pwd])
# 涉及写操作注意要提交
conn.commit()
# 关闭连接
# 获取最新的那一条数据的ID
last_id = cursor.lastrowid
print("最后一条数据的ID是:", last_id)
cursor.close()
conn.close()
删除操作
import pymysql
# 建立连接
conn = pymysql.connect(
host="192.168.0.103",
port=3306,
user="root",
password="123",
database="xing",
charset="utf8"
)
# 获取一个光标
cursor = conn.cursor()
# 定义将要执行的SQL语句
sql = "delete from userinfo where user=%s;"
name = "june"
# 拼接并执行SQL语句
cursor.execute(sql, [name])
# 涉及写操作注意要提交
conn.commit()
# 关闭连接
cursor.close()
conn.close()
查询数据
import pymysql
conn = pymysql.connect (
host='192.168.0.103',
port=3306,
user='root',
password='123',
database='xing',
charset='utf8'
)
# 获取一个光标
cursor = conn.cursor(cursor=pymysql.cursors.DictCursor) # 返回字典数据类型
# 定义将要执行的sql语句
sql = 'select user,pwd from userinfo;'
# 拼接并执行sql语句
cursor.execute(sql)
# 取到查询结果
ret1 = cursor.fetchone() # 取一条
ret2 = cursor.fetchmany(3) # 取三条
ret3 = cursor.fetchone() # 取一条
cursor.close()
conn.close()
print(ret1)
print(ret2)
print(ret3)
1
2
3
4
5
6
# 可以获取指定数量的数据
cursor.fetchmany(3)
# 光标按绝对位置移动1
cursor.scroll(1, mode="absolute")
# 光标按照相对位置(当前位置)移动1
cursor.scroll(1, mode="relative")
数据回滚
import pymysql
# 建立连接
conn = pymysql.connect(
host="192.168.0.103",
port=3306,
user="root",
password="123",
database="xing",
charset="utf8"
)
# 获取一个光标
cursor = conn.cursor()
# 定义将要执行的SQL语句
sql1 = "insert into userinfo (user, pwd) values (%s, %s);"
sql2 = "insert into hobby (id, hobby) values (%s,%s);"
user = "july1"
pwd = "july1"
id = "我是错误的id" #id = "3"
hobby = "打游戏"
try:
# 拼接并执行SQL语句
cursor.execute(sql1, [user, pwd])
print(sql1)
cursor.execute(sql2, [id, hobby]) # 报错的SQL语句
# 涉及写操作注意要提交
conn.commit()
except Exception as e:
print(str(e))
# 有异常就回滚
conn.rollback()
# 关闭连接
cursor.close()
conn.close()
参考资料
https://www.cnblogs.com/xfxing/p/9322199.html