mysql的数据存储

# pycharm 连接mysql

import pymysql

username = input("输入用户名:")
pwd = input("输入密码:")

# 建立连接
conn = pymysql.connect(
    host = 'localhost',
    user='root',
    password='',
    database='pymysql',
    port=3306,
    charset='utf8'
)

# 创建游标
cur = conn.cursor()
sql = 'select * from user（表名） where username（字段）="%s"'%(username)
print(sql)

ret = cur.execute(sql)
print(ret) # 1 说明连接成功

#关闭游标
cur.close()
conn.close()

插入

# 插入
import pymysql

username = input("输入用户名:")
password = input("输入密码:")

# 建立连接
conn = pymysql.connect(
    host = 'localhost',
    user='root',
    password='',
    database='pymysql',
    port=3306,
    charset='utf8'
)

# 创建游标
cur = conn.cursor()
# sql = 'select * from user（表名） where username（字段）= "%s"'%(username)
# print(sql)

sql = """insert into user（表名）(id,username,password) values(null,%s,%s)"""

cur.execute(sql,(username,password))
conn.commit()

#关闭游标
cur.close()
conn.close()

# 查找
import pymysql

# 建立连接
conn = pymysql.connect(
    host = 'localhost',
    user='root',
    password='',
    database='pymysql',
    port=3306,
    charset='utf8'
)

# 创建游标
cur = conn.cursor()
# sql = 'select * from user（表名） where username（字段） ="%s"'%(username)
# print(sql)

# select username,password from user where id = 1
# select * from user

sql = """
select * from user
"""
cur.execute(sql)
# result = cur.fetchall()
result = cur.fetchmany(2)

print(result)

#关闭游标
cur.close()
conn.close()

# 删除
import pymysql

# 建立连接
conn = pymysql.connect(
    host = 'localhost',
    user='root',
    password='',
    database='pymysql',
    port=3306,
    charset='utf8'
)

# 创建游标
cur = conn.cursor()

# sql = """
# delete from user where id= 1
# """
# cur.execute(sql)
# conn.commit()

sql = """
update user（表名） set username（字段）= 'aaa' where id（字段） = 2
"""
cur.execute(sql)
conn.commit()

#关闭游标
cur.close()
conn.close()