使用pymysql連接mysql數據庫

建立鏈接

import pymysql

conn = pymysql.connect(
    host='localhost',
    user='root',
    password='1111111',
    port=3306,
    database='demo_pymysql'
)

cursor = conn.cursor()
res = cursor.execute('select * from user;')
print(cursor.fetchall())
conn.close()

插入數據

import pymysql

conn = pymysql.connect(
    host='localhost',
    user='root',
    password='22222',
    port=3306,
    database='demo_pymysql'
)

cursor = conn.cursor()


sql = """
insert into user(id, username, age, password) values(null, %s, %s, %s)
"""
username = 'dd'
age = 21
password = '123123'
cursor.execute(sql, (username, age, password))
conn.commit()
# 注意需要coomit後纔會插入
res = cursor.execute('select * from user;')
print(cursor.fetchall())

conn.close()

查找數據

使用pymysql查詢數據。可以使用fetch方法
1、fetchone():這個方法每次獲取一條數據
2、fetchall():這個方法接收全部的返回值
3、fetchmany()：這個方法可以返回指定條數的數據

import pymysql

conn = pymysql.connect(
    host='localhost',
    user='root',
    password='',
    port=3306,
    database='demo_pymysql'
)

cursor = conn.cursor()
sql = """
select username, age from user where id > 2;
"""
cursor.execute(sql)
res = cursor.fetchmany(10)
print(res)
conn.close()

刪除數據

sql = """
delete from user where id=3
"""
cursor.execute(sql)
conn.commit()

需要注意的是在執行刪除語句後，需要commit才能生效

更新數據

sql = """
update user set username='luole'  where id=1
"""
cursor.execute(sql)
conn.commit()

需要注意的是在執行更新語句後，需要commit才能生效