Question

我的更新触发器：

    declare @NewValue NVARCHAR(4000) = '';
        declare @OldValue NVARCHAR(4000) = '';

    select @OldValue =''
                + CASE WHEN i.Name <> d.Name THEN '"Name": "'+ d.Name +'", ' ELSE '' END+
                + CASE WHEN i.Address1 <> d.Address1 THEN '"Address1": "'+ d.Address1 +'", ' ELSE '' END+
                '' FROM 
                inserted i
                JOIN deleted d on (i.AccountId = d.AccountId) ;

    select @NewValue = ''
                + CASE WHEN d.Name = NULL OR i.Name <> d.Name THEN '"Name": "'+ i.Name +'", ' ELSE '' END+
                + CASE WHEN d.Address1 = NULL OR i.Address1 <> d.Address1 THEN '"Address1": "'+ i.Address1 +'", ' ELSE '' END+
                '' FROM 
                inserted i
                JOIN deleted d on (i.AccountId = d.AccountId) ;

if @NewValue <> '' AND @OldValue <> '' AND @NewValue <> @OldValue
            INSERT INTO Auditlog (OtherId, TableName, ActionDate, ActionBy, Operation, ActionType)
                    SELECT 
                        i.AccountId, 'Accounts', getdate(), '', 'Update', '' 
                    FROM 
                        inserted i

            INSERT INTO AuditlogDetails (AuditlogId, OldValue , NewValue)
                    values (IDENT_CURRENT('dbo.Auditlog'), N'[{'+ @OldValue +'}]', N'[{'+ @NewValue +'}]')

但是这个触发器只是插入表AuditlogDetails而@NewValue是NULL：例如我有一个记录名=＆＃34; abc＆＃34;，地址1 = NULL当我更新该记录时Address1 =＆＃34; adasf＆＃34 ;然后@NewValue为NULL我希望@NewValue是[{＆＃34;地址1＆＃34;：＆＃34; adasf＆＃34;}]有人帮助我

Answer 1

更改您的NULL比较

select @NewValue = ''
                + CASE WHEN d.Name = NULL OR i.Name <> d.Name THEN '"Name": "'+ i.Name +'", ' ELSE '' END+
                + CASE WHEN d.Address1 = NULL OR i.Address1 <> d.Address1 THEN '"Address1": "'+ i.Address1 +'", ' ELSE '' END+
                '' FROM 
                inserted i
                JOIN deleted d on (i.AccountId = d.AccountId) ;

在上面的行中，您比较了d.Name = NULL和d.Address1 = NULL。 Null是我们不知道的东西。因此，您无法将NULL与等号进行比较。

前：

Declare @var varchar(20) = NULL;
IF (@var = NULL)
BEGIN 
  PRINT 'Equals work'
END

IF (@var IS NULL)
BEGIN
    PRINT 'IS NULL WORK'
END

但是当我们使用属性SET ANSI_NULLS (Transact-SQL)

时，上述行为将会改变

将其更改为d.Name is NULL。 d.Address1 is NULL

更新触发器在更新记录有一些字段为空时不起作用

1 个答案: