python pymysql操作mysql

连接数据库

conn = pymysql.connect(host='127.0.0.1', user='root', password='root', database='demo')
cur = conn.cursor()  # 游标
# cur = conn.cursor(cursor=pymysql.cursors.DictCursor)    # 获取字典形式数据
#cur.rowcount()   # 获取查出多少行，便于fetchone()取所有数据

cur.execute("select * from student")    # sql语句

cur.close()
conn.close()

 

增删改查

# 查询
cur.rowcount()   # 获取查出多少行，便于fetchone()取所有数据
for i in range(cur.rowcount):
    ret = cur.fetchone()
    print(ret)

# 获取数据会有游标记录，如下面会获取第1条数据、获取2到第11条、获取12到最后数据
ret = cur.fetchone()  # 获取一条数据
print(ret)
ret1 = cur.fetchmany(10)  # 获取指定数量数据
print(ret1)
ret2 = cur.fetchall()  # 获取所有数据
print(ret2)


# 增加、删、该
try:
    cur.execute('insert into student values(21,"路飞",18)')            # 添加数据
    cur.execute('update student set name = "布鲁克" where id = 17')    # 修改数据
    cur.execute('delete from student where id = 16')                    # 删除数据
    conn.commit()           # 提交数据库
except Exception as e:
    print(e)
    conn.rollback()         # 错误回滚

 

sql注入

# 数据注入
usr = input("user")
pwd = input("pwd")
cur = conn.cursor()
sql = "select * from login where user = %s and password = %s"    # 不要在这里进行数据拼接
cur.execute(sql, (usr, pwd))        # 防止sql注入
print(cur.fetchone())