32-Python3 MySQL(mysql-connector)

32-Python3 MySQL(mysql-connector)

'''
创建数据库连接
'''
import pymysql

mydb = pymysql.connect(
host = '127.0.0.1',
user = 'root',
passwd = 'root',
db = 'jo_db1',
port = 3306,
charset = 'utf8'
)
print('mydb:',mydb)

mycursor = mydb.cursor()

'''
创建数据库
'''
# mycursor.execute('CREATE DATABASE runoob_db1') ##CREATE DATABASE必须为大写，否则报语法错误

##输出所有数据库列表
mycursor.execute('SHOW DATABASES')
for x in mycursor:
    print(x)

'''
创建数据库表
'''
import  pymysql
mydb = pymysql.connect(
host = '127.0.0.1',
user = 'root',
passwd = 'root',
database = 'runoob_db1'
)
mycursor = mydb.cursor()

##创建数据库
mycursor.execute('CREATE TABLE site(name VARCHAR(255),url VARCHAR(255))')

##打印输出数据库中所有的表
mycursor.execute('SHOW TABLES')
for x in mycursor:
    print(x)

##主键设置:给已创建的表添加主键
mycursor.execute('ALTER TABLE site ADD COLUMN id INT AUTO_INCREMENT PRIMARY KEY')

##主键设置:创建表时添加主键
import pymysql
mydb = pymysql.connect(host = '127.0.0.1',user = 'root',passwd = 'root',database = 'runoob_db1' )

mycursor = mydb.cursor()
mycursor.execute('CREATE TABLE site2 (id INT AUTO_INCREMENT PRIMARY KEY ,name VARCHAR (255),site VARCHAR (255))')
'''
插入数据
'''
import pymysql
mydb = pymysql.connect(host = '127.0.0.1',user = 'root',passwd = 'root',database = 'runoob_db1' )
mycursor = mydb.cursor()
mycursor.execute('CREATE TABLE site2 (id INT AUTO_INCREMENT PRIMARY KEY ,name VARCHAR (255),site VARCHAR (255))')
##插入一条数据
val =('RUNOOB','https://www.runoob.com')
mycursor.execute(sql,val)
mydb.commit()
print(mycursor.rowcount,'记录插入成功。')

##批量插入
val = [
('TAOBAO','https://www.taobao.com'),
('Google','https://google.com'),
('BaiDu','https://baidu.com'),
]
mycursor.executemany(sql,val)
mydb.commit()
print(mycursor.rowcount,'批量记录插入成功。')
##获取插入数的id
val = ('Zhihu','https://www.zhihu.com')
mycursor.execute(sql,val)
mydb.commit()
print('1条记录已插入，ID为：',mycursor.lastrowid)

'''
查询数据
'''
import pymysql

mydb = pymysql.connect(host = '127.0.0.1',user = 'root',passwd = 'root',database = 'runoob_db1')
mycursor = mydb.cursor()
mycursor.execute('SELECT * FROM site2')

##获取所有数据
# myresult = mycursor.fetchall()

##如果只想获取一条数据的话
myresult = mycursor.fetchone()

for x in myresult:
    print(x)

##where条件语句(完整版)------------------------------------------------------
import pymysql
mydb = pymysql.connect(host = '127.0.0.1',user = 'root',passwd = 'root',database = 'runoob_db1')
mycursor = mydb.cursor()
sql = "select * from site2 where name = 'runoob'"
mycursor.execute(sql)
myresult = mycursor.fetchall()
for x in myresult:
    print(x)
##模糊查询完整版
import pymysql
mydb = pymysql.connect(host = '127.0.0.1',user = 'root',passwd = 'root',database = 'runoob_db1')
mycursor = mydb.cursor()
sql = "select * from site2 where site like '%oo%'"
#sql2 = "select * from site2"
mycursor.execute(sql)
myresult = mycursor.fetchall()
for x in myresult:
    print(x)
##防止sql注入的
pass
##排序（完整版）
import pymysql
mydb = pymysql.connect(host = '127.0.0.1',user = 'root',passwd = 'root',database = 'runoob_db1')
mycursor = mydb.cursor()
#sql = "select * from site2 order by name "  #默认的正排序
sql = "select * from site2 order by name desc"  #倒排序
sql = "select * from "
mycursor.execute(sql)
myresult = mycursor.fetchall()
for x in myresult:
    print(x)
##Limit
import pymysql
mydb = pymysql.connect(host = '127.0.0.1',user = 'root',passwd = 'root',database = 'runoob_db1')
mycursor = mydb.cursor()
sql = "select * from site2"
#sql = "select * from site2 order by name "  #默认的正排序
#sql = "select * from site2 order by name desc"  #倒排序
#sql = "select * from site2 limit 3" # 查询前3条记录
#sql = "select * from site2 limit 2 offset 1"  #从第1条数据开始向上取3条记录
mycursor.execute(sql)
myresult = mycursor.fetchall()
for x in myresult:
    print(x)

'''
删除记录
'''
import pymysql
mydb = pymysql.connect(host = '127.0.0.1',user = 'root',passwd = 'root',database = 'runoob_db1')
mycursor = mydb.cursor()

#插入数据
sql= "insert into site2 (name,site) values (%s,%s)"
val = ('Heheda','https://wwww.heheda.com')
mycursor.execute(sql,val)
mydb.commit()

#查询所有结果
sql = "select * from site2"
mycursor.execute(sql)
myresult = mycursor.fetchall()
for x in myresult:
    print(x)

#删除数据
sql = "delete from site2 where name = 'Heheda'"
mycursor.execute(sql)
mydb.commit()

'''
更新表数据
'''

'''
删除表
'''