Python | 关系数据库mysql基本操作练习

import pymysql
"""1.创建数据库"""
db=pymysql.connect(host='localhost',user='root',password='123456',port=3306)   #连接mysql
cursor=db.cursor()  #z设置光标
sql='CREATE DATABASE pymysql_test' #sql语句
cursor.execute(sql)  #执行
db.close() #关闭链接
"""2.创建表"""
db=pymysql.connect(host="localhost",user='root',password='123456',port=3306,db='pymysql_test')
cursor=db.cursor()
sql='CREATE TABLE test(id varchar(255) not null ,name varchar(255) not null ,age varchar(255) not null ,primary key (id))'
try:
    cursor.execute(sql)
    print('ok')
except Exception as e:
    print('eorr',e)
"""3.增"""
'第一种：写的比较死版'
db=pymysql.connect(host="localhost",user='root',password='123456',port=3306,db='pymysql_test')
cursor=db.cursor()
sql='insert into test(id,name,age) values (01,"tom",12)'
try:
    cursor.execute(sql)
    db.commit()
    print('ok')
except Exception as e:
    print('erro',e)

'第二种：灵活的写法'
data={
    'id':'02',
    'name':'alex',
    'age':'12'
}
keys=','.join(data.keys())
values=','.join(['%s']*len(data))
db=pymysql.connect(host="localhost",user='root',password='123456',port=3306,db='pymysql_test')
cursor=db.cursor()
sql='insert into test({keys}) values ({values})'.format(keys=keys,values=values)
try:
    cursor.execute(sql,tuple(data.values()))
    db.commit()
    print('ok')
except Exception as e:
    print('erro',e)
"""4.删"""
db=pymysql.connect(host="localhost",user='root',password='123456',port=3306,db='pymysql_test')
cursor=db.cursor()
sql='DELETE FROM test where name="tom"'
try:
    cursor.execute(sql)
    db.commit()
    print('ok')
except Exception as e:
    print('erro',e)
"""5.改"""
db=pymysql.connect(host="localhost",user='root',password='123456',port=3306,db='pymysql_test')
cursor=db.cursor()
sql='UPDATE test SET age="200" where id="02"'
try:
    cursor.execute(sql)
    db.commit()
    print('ok')
except Exception as e:
    print('erro',e)
"""6.查"""
db=pymysql.connect(host="localhost",user='root',password='123456',port=3306,db='pymysql_test')
cursor=db.cursor()
sql='SELECT * FROM test'
try:
    cursor.execute(sql)
    data1=cursor.fetchone()
    data2 = cursor.fetchall()
    print('ok')
    print(data1)
    print(data2)
except Exception as e:
    print('erro',e)