Question

在这里，我有两个表Customer_Account和Cust_Transaction，它们具有下面的属性，但没有太多细节，需要指出的是，表之间的关系是Account_ID：

Cust_Account(
Account_ID PK,
Account_Name,
Account_Balance)

Cust_Transaction(
Trn_ID PK,
Trn_Date,
Trn_Amount,
Trn_Type,
Account_ID FK)

表中的数据如下：

    |---------------------------------------|
    |Account_ID|Account_Name|Account_Balance|
    |---------------------------------------|
    |    0001  |    Ahmad   |      0        |
    |---------------------------------------|



    |-----------------------------------------------|
    |Trn_ID|Trn_Date |Trn_Amount|Trn_Type|Account_ID|
    |---------------------------------------------- |
    | 001  |01/01/20 |   4000   | Credit |  001     |
    |-----------------------------------------------|

我想要一个解决方案，每当我使用以上数据输入Cust_Transaction时，它还应将金额添加到他在Account_Balance中的帐户，并且无论何时“提取”，都应减去{{ 1}}同时删除交易时，它也应减去Account_Balance。请以哪种方式解决我。谢谢，

Answer 1

您可以在交易表上创建TRIGGER，它会完美地处理表中的余额：

CREATE OR ALTER TRIGGER TR_Cust_Transaction ON Cust_Transaction
FOR INSERT, UPDATE, DELETE
AS
BEGIN
    SET NOCOUNT ON
    UPDATE CA SET Account_Balance = ISNULL(Account_Balance,0) + ISNULL(I.Trn_Amount,0) - ISNULL(D.Trn_Amount,0) 
    FROM Cust_Account CA 
    LEFT JOIN (SELECT Account_Id, SUM(Trn_Amount * IIF(Trn_Type = 'Credit', 1, -1)) Trn_Amount FROM INSERTED GROUP BY Account_Id) I ON CA.Account_Id = I.Account_Id
    LEFT JOIN (SELECT Account_Id, SUM(Trn_Amount * IIF(Trn_Type = 'Credit', 1, -1)) Trn_Amount FROM DELETED GROUP BY Account_Id) D ON CA.Account_Id = D.Account_Id
END

了解更多here。

提示：如果您永远不会在Cust_Transaction上插入/更新/删除多条记录，则可以直接连接到Inserted和Deleted表，而无需按account_id按数据分组。

客户帐户余额如何受到SQL Server中客户交易表的影响？

1 个答案: