主页 / 问题 / 1406972
Accepted
MayorLeon19
Asked:2022-07-06 02:46:29 +0000 UTC2022-07-06 02:46:29 +0000 UTC

如何使sqlite3在更改python中的值时没有负数

  • 772

如何使其在 sqlite3 中更改值时没有负数（检查）在此处输入图像描述

编码：

@slash.slash(
    name="takecash",
    description="- вычесть количество ар",
    guild_ids=[924384808187093032],
    options=[
        create_option(
            name="member",
            description="пользователь",
            required=True,
            option_type=6,
        ),
        create_option(
            name="amount",
            description="количество аров",
            required=True,
            option_type=10,
        ),
    ]
)

@commands.has_any_role(971817475543035975)
async def takecash(ctx, member: discord.Member, amount:str):
    if amount < 1:
        await ctx.send(f"**{ctx.author}**, укажите сумму больше 1")
    else:
        cursor.execute("UPDATE users SET cash = cash - {} WHERE id = {}".format(amount, member.id))
        connection.commit()
python

3 个回答

  1. 在数据库级别，您可以添加

    ALTER TABLE USERS
   ADD CONSTRAINT checkCashIsPositive CHECK(CASH >= 0);

    那么数据库将不允许输入这样的值，抛出异常。

    • 0

  2. 如果很清楚，那么您可以这样做：

    这样的解决方案将可以正确处理案例（向用户发送消息，阻止帐户等）而不会导致程序异常

    from pathlib import Path
from sqlite3 import connect

conn = connect(Path('test.sqlite'))

cur = conn.cursor()
conn.execute(
    """
        create table if not exists test
    (
        key integer primary key ,
        val integer
    );
    """
)
cur.execute(
    """
    insert into test (key, val) VALUES (1, 150) 
      on conflict (key) do update set val = excluded.val;
    """
)
conn.commit()

for _ in range(20):
    cur.execute(
        """
        update test set val = val - ? where key = ? returning val;
        """, [
            20,
            1
        ]
    )
    val, = cur.fetchone()
    if val >= 0:
        print(val)
        conn.commit()
        continue
    else:
        print('do something')
        conn.rollback()
        break

cur.execute(
    """
    select val from test where key = ?;
    """, [1]
)
val, = cur.fetchone()
print(
    f'check val in db `{val = }`'
)


# 130
# 110
# 90
# 70
# 50
# 30
# 10
# do something
# check val in db `val = 10`
    • 0
  3. Best Answer

    已解决：创建类型变量

    member_cash = cursor.execute("SELECT cash FROM users WHERE id = {}".format(member.id)).fetchone()[0]

    接着

    if amount > member_cash:
  print('err')
else:
  print('pass')
    • 0

相关问题