pymysql库对数据库进行查询

import pymysql

# 和数据库创建连接
# host：需要连接的数据库地址；port：端口号；database：数据库
conn = pymysql.Connect(host='127.0.0.1', port=3306, database='books',
                       user='root', password='root', charset='utf8')
# 创建对象
cursor = conn.cursor()

# 发送sql语句
sql = 'select * from t_book'

# 执行sql语句
cursor.execute(sql)

# 结果获取,获取所有结果
rows = cursor.fetchall()
# print('所有结果：', rows)
# 遍历每一个数据
for row in rows:
    print(row)

# 结果获取，获取行数
print('响应结果行数：', cursor.rowcount)

# 资源释放
cursor.close()
conn.close()

pymysql库对数据库进行增加

import pymysql

# 创建连接
conn = pymysql.Connect(host='127.0.0.1', port=3306, database='books',
                       user='root', password='root', charset='utf8', autocommit=True)
# 创建对象
cursor = conn.cursor()

# 发送 sql
sql = "insert into t_book values(4,'水浒传','2021-03-13',100,50,0)"
cursor.execute(sql)
print('新增的行数：', cursor.rowcount)
cursor.execute('select * from t_book')
rows = cursor.fetchall()
for row in rows:
    print(row)
    
# 释放资源
cursor.close()
conn.close()

pymysql库对数据库进行删除

import pymysql

conn = pymysql.Connect(host='127.0.0.1', port=3306, database='books',
                       user='root', password='root', charset='utf8', autocommit=True)
cursor = conn.cursor()

sql = "delete from t_book where id=4"
cursor.execute(sql)
print('删除的行数：', cursor.rowcount)

cursor.close()
conn.close()

pymysql库对数据库进行修改

import pymysql

conn = pymysql.Connect(host='127.0.0.1', port=3306, database='books',
                       user='root', password='root', charset='utf8', autocommit=True)
cursor = conn.cursor()

sql = "update t_book set title='西游记后传' where id=4"
cursor.execute(sql)
print('修改的行数：', cursor.rowcount)
cursor.execute('select * from t_book')
rows = cursor.fetchall()
for row in rows:
    print(row)

cursor.close()
conn.close()