一、pymysql的基本使用

import pymysql

user = input('user>>>:').strip()
pwd = input('password>>>:').strip()

# 建立連線
conn = pymysql.connect(
    host='127.0.0.1',
    port=3306,
    user='root',
    password='112233',
    db='db8',
    charset='utf8'
)

# 拿到遊標

cursor = conn.cursor()

# 執行sql語句
 


sql = 'select * from userinfo where user = "%s" and pwd="%s"' % (user, pwd)

rows = cursor.execute(sql)

cursor.close()
conn.close()

# 進行判斷
if rows:
    print('登陸成功')
else:
    print('登陸失敗')

二、解決sql注入問題

import pymysql

user = input('user>>>:').strip()
pwd = input('password>>>:
 
').strip()

# 建立連線
conn = pymysql.connect(
    host='127.0.0.1',
    port=3306,
    user='root',
    password='112233',
    db='db8',
    charset='utf8'
)

# 拿到遊標

cursor = conn.cursor()

# 執行sql語句

# sql = 'select * from userinfo where user = "%s" and pwd="%s"' % (user, pwd)
# print(sql)
'''
方式一
# select * from userinfo where user = "egon" -- xxxxxx" and pwd=""
# 在sql中 --之後的都代表註釋掉。所以等於只查 where user ="egon"

方式二
# select * from userinfo where user = "xxx" or 1=1 -- hahahaha" and pwd=""
# select * from userinfo where user = "xxx" or 1=1 其實是執行了這個,1=1永遠成立
 
'''

# 防止sql注入的方法,過濾到非法操作

sql = 'select * from userinfo where user = %s and pwd= %s '
rows = cursor.execute(sql, (user, pwd))  # 將使用者密碼在這裡傳入，pymysql內建的功能就能幫助你過濾

cursor.close()
conn.close()

# 進行判斷
if rows:
    print('登陸成功')
else:
    print('登陸失敗')

三、pymysql之增刪改查

# 1、增刪改
import pymysql

# 建立連結
conn = pymysql.connect(
    host='127.0.0.1',
    port=3306,
    user='root',
    password='112233',
    db='db8',
    charset='utf8'
)
# 拿遊標
cursor = conn.cursor()

# 執行sql
# 增、刪、改
sql = 'insert userinfo(user,pwd) values(%s,%s)'  # 刪改把insert換成相應的關鍵字就行
# cursor.execute(sql,('wxx','123'))

# rows = cursor.executemany(sql, [('yxx', '123'), ('egon1', '123'), ('egon2', '123')])  # 插入多條記錄
# print(rows) # 3

rows = cursor.executemany(sql,[('egon3','123'),('egon4','123'),('egon5','123')])
print(cursor.lastrowid)  # 7 插入之前id走到哪了，在插入三條就是7、8、9

conn.commit()  # 執行commit才會對資料庫進行操作

# 關閉遊標和連結
cursor.close()
conn.close()


# 2、查詢

import pymysql

# 建立連結
conn = pymysql.connect(
    host='127.0.0.1',
    port=3306,
    user='root',
    password='112233',
    db='db8',
    charset='utf8'
)
# 拿遊標
cursor = conn.cursor(pymysql.cursors.DictCursor)  # 以字典的形式取出來

# 執行sql
# 查詢
rows = cursor.execute('select * from userinfo;')
# print(rows)  6

# print(cursor.fetchone())  # 取一行,直到取到沒有就顯示None
# print(cursor.fetchone())
# print(cursor.fetchmany(5))  # 指定取幾行

# print(cursor.fetchall())  # 取全部


# cursor.scroll(3,'absolute') # 絕對位置
# print(cursor.fetchone())  # 第四條

print(cursor.fetchone())
cursor.scroll(2,mode='relative')  # 基於當前的位置往後在跳兩個
print(cursor.fetchone()) # 4 ，如果用absolute就是3


# 關閉遊標和連結
cursor.close()
conn.close()