连接数据库操作
mysql主机:
1. 创建一个可以远程登陆的用户；
2. 给这个用户授权， 可以对哪个数据库操作;
3. 看防火墙是否管理;
python3主机:
1. 测试是否可以成功连接mysql主机?
2. 修改pycharm的解释器(安装pymysql模块)位置， 编写mysql代码，
***如何自动提交对数据库的操作:
1. # conn.commit()
2. 创建连接时，就指定:
pymysql.connect(host='192.168.122.170', user='hello',
password='hello', charset='utf8', autocommit=True)
"""
import pymysql
# 1. 连接数据库， host, user, passwd, charset
conn = pymysql.connect(user='root',
password='971203', charset='utf8', autocommit=True)
# 2. 创建一个游标， 用来给数据库发送sql语句的；
cur = conn.cursor()
# 3. 对于数据库实现增删改查操作
# 选择需要操作的数据库
conn.select_db('westos')
try:
# 要执行的sql
# create_sql = 'create table myuser (name varchar(30), age int );'
# # delete_sql
# # update_sql
# cur.execute(create_sql)
#
#
# insert_sqli1 = 'insert into myuser VALUES ("user3", 100);'
# insert_sqli2 = 'insert into myuser VALUES ("user4", 100);'
# cur.execute(insert_sqli1)
# cur.execute(insert_sqli2)
#
#
# delete_sqli = 'delete from myuser where name="user2";'
# cur.execute(delete_sqli)
# # 提交所有对数据库的操作;
# conn.commit()
#
#
# # **************批量对数据实现增删改;
# users = [('user'+str(i), i) for i in range(100)]
# insert_sqli = 'insert into myuser VALUES (%s, %s);'
# cur.executemany(insert_sqli, users)
#
#
select_sqli = 'select * from myuser;'
res = cur.execute(select_sqli)
# print("查看语句的返回结果:", res)
# *****************88查看查看表中的数据
# # cur.fetchone类似与文件的操作f.readline, 每次只读取一条记录;
print("查找一条记录:", cur.fetchone())
print("查找一条记录:", cur.fetchone())
print("查找一条记录:", cur.fetchone())
print("查找一条记录:", cur.fetchone())
# cur.fetchmany， 类似于f.readlines, 返回的是一个元组；
print("查找5条记录:",cur.fetchmany(5))
# cur.fetchall返回的是一个元组；
print("查找1所有记录", cur.fetchall())
# 移动游标的位置, 到记录的最开始
# cur.scroll(0, mode='absolute')
# print("查找2所有记录", cur.fetchall())
cur.scroll(-10, mode='relative')
print("查找2所有记录", cur.fetchall())
except Exception as e:
print("Fail:", e)
else:
print("Success")
# 4. 先关闭游标
cur.close()
# 5. 关闭数据库连接
conn.close()
获取字段名和信息
import pymysql
conn = pymysql.connect(user='root',
password='971203', charset='utf8', autocommit=True,
db='westos')
with conn:
print("is_open", conn.open)
cur = conn.cursor()
res = cur.execute('select * from westosuser;')
desc = cur.description
print("表的描述:",desc )
print(res)
print("表头", ",".join([item[0] for item in desc]))
cur.close()
银行转账操作
import pymysql
class TransferMoney(object):
def __init__(self, conn):
self.conn = conn
self.cursor = conn.cursor()
def transfer(self, source_accid, target_accid, money):
"""
转账方法:
# 1. source_accid帐号是否存在；
# 2. target_accid帐号是否存在；
# 3. 是否有足够的钱
# 4. source_accid扣钱
# 5. target_acci加钱
# 6. 提交对数据库的操作
:param source_accid: 源帐号id
:param target_accid: 目标帐号id
:param money: 转账金额
:return: bool
"""
self.check_account_avaiable(source_accid)
self.check_account_avaiable(target_accid)
self.has_enough_money(source_accid, money)
try:
self.reduce_money(source_accid, money)
print(a)
self.add_money(target_accid, money)
self.conn.commit()
except Exception as e:
self.conn.rollback()
else:
print("%s给%s转账%s成功" %(source_accid, target_accid, money))
def check_account_avaiable(self, accid):
"""判断帐号是否存在， 传递参数为帐号id"""
select_sqli = 'select * from bankData where id=%s' %(accid)
print("execute sql:", select_sqli)
res = self.cursor.execute(select_sqli)
if res == 1:
return True
else:
raise Exception("帐号%s不存在" %(accid))
def has_enough_money(self, accid, money):
"""是否有足够的钱"""
select_sqli = 'select money from bankData where id=%s' %(accid)
print('execute sql:', select_sqli)
self.cursor.execute(select_sqli)
acc_money = self.cursor.fetchone()[0]
print(acc_money, type(acc_money))
if acc_money >= money:
return True
else:
raise Exception("账户%s没有足够的金额， 当前余额为%s" %(accid, acc_money))
def reduce_money(self, accid, money):
try:
update_sqli = 'update bankData set money=money-%s where id="%s"' %(money, accid)
print("redcue_money sql:", update_sqli)
self.cursor.execute(update_sqli)
except Exception as e:
print('Error:',e)
def add_money(self, accid, money):
try:
update_sqli = 'update bankData set money=money+%s where id="%s"' %(money, accid)
print("add_money sql:", update_sqli)
self.cursor.execute(update_sqli)
except Exception as e:
print('Error:',e)
def __del__(self):
self.cursor.close()
if __name__ == '__main__':
conn = pymysql.connect(user='root',
password='971203', charset='utf8',
db='westos')
trans = TransferMoney(conn)
try:
assert trans.check_account_avaiable('610001') == True
except AssertionError as e:
print(e)
else:
print("测试用例全部通过.....")
trans.has_enough_money('610001', 1000)
trans.has_enough_money('610001', 1001)
trans.reduce_money('610001', 200)
trans.add_money('610001', 200)
trans.transfer('610003', '610002', 100)
def create_data():
conn = pymysql.connect(user='root',
password='971203', charset='utf8',
autocommit=True, db='westos')
cur = conn.cursor()
try:
create_sqli = 'create table bankData( id int PRIMARY KEY, ' \
'name varchar(10), money FLOAT);'
cur.execute(create_sqli)
except Exception as e:
print("Error: 表已经创建", e)
else:
print("表创建成功")
a = 'set names latin1;'
cur.execute(a)
try:
users = [(610001, '张三', 1000), (610002, '李四', 1000),(610003, '粉条', 1000)]
insert_sqli = 'insert into bankData VALUES (%s, %s, %s);'
cur.executemany(insert_sqli, users)
except Exception as e:
print('Error:', e)
else:
print("初始化数据成功!")
cur.close()
conn.close()
