外键的审计触发器

Question

下面的代码是我的Branch 表的审核触发器。它能够记录Branch 表中的任何编辑或插入更改。

但是，我有一个指向 BranchZone 表的外键 BranchZoneID。我想这样做，以便记录对此外键的任何更改，并且它将显示BranchZone 表中的BranchZoneName 而不是BranchZoneID。

我尝试使用代码为外键属性BranchZoneID 创建触发器。但是，我无法为其创建工作触发器。

BranchZoneID 的触发器不起作用。我需要改变什么？

create trigger Branch_Audit
on dbo.Branch
after insert, update
not for replication
as
begin
  set nocount on;

  declare @operation char(10) = case when exists (select * from deleted) then 'Edit' else 'Insert' end;

  insert AuditLog
(TableName, ModifiedBy, AuditDateTime, AuditAction, ID, ChangedColumn, OldValue, NewValue)
    select
      'Branch', suser_sname(), getdate(), @operation, I.BranchZoneID,
      'BranchName', convert(varchar(21),D.BranchName), convert(varchar(21),I.BranchName)
    from inserted I
    left outer join deleted D on I.BranchID = D.BranchID
    where coalesce(I.BranchName,'') <> coalesce(D.BranchName,'')
    and update(BranchName)
    union all

    select
    'Branch', suser_sname(), getdate(), @operation, I.BranchID,
    'BranchAddress', D.BranchAddress, I.BranchAddress
    from inserted I
    left outer join deleted D on I.BranchID = D.BranchID
    where coalesce(I.BranchAddress,'') <> coalesce(D.BranchAddress,'')
    and update(BranchAddress)
    union all


    select
    'Branch', suser_sname(), getdate(), @operation, I.BranchID,
    'BranchGeoLocationLat', D.BranchGeoLocationLat, I.BranchGeoLocationLat
    from inserted I
    left outer join deleted D on I.BranchID = D.BranchID
    where coalesce(I.BranchGeoLocationLat,'') <> coalesce(D.BranchGeoLocationLat,'')
    and update(BranchGeoLocationLat)
    union all


    select
    'Branch', suser_sname(), getdate(), @operation, I.BranchID,
    'BranchGeoLocationLong', D.BranchGeoLocationLong, I.BranchGeoLocationLong
    from inserted I
    left outer join deleted D on I.BranchID = D.BranchID
    where coalesce(I.BranchGeoLocationLong,'') <> coalesce(D.BranchGeoLocationLong,'')
    and update(BranchGeoLocationLong)
    union all

    select
    'Branch', SUSER_SNAME(), GETDATE(), @operation, I.BranchID,
    'BranchZoneID', OWD.BranchZoneName, NWD.BranchZoneName
    from inserted I
    left outer join deleted D on I.BranchID = D.BranchID
    where coalesce(I.BranchZoneID,'') <> coalesce(D.BranchZoneID,'')
    and update(BranchZoneID)
    -- Fetch Branch Zone Name
    on deleted.BranchZoneID = OWD.BranchZoneID
    join dbo.BranchZone NWD
    on inserted.BranchZoneID = NWD.BranchZoneID

end;

Answer 1

您只是对您的加入感到困惑......正确加入并且它按预期工作。请记住，当使用表别名时，从那时起您只能使用别名引用表，例如I 而不是 Inserted。

还假设BranchZoneID 是int，您需要将coalesce 设置为未使用的int，例如0 不是空字符串。

select
    'Branch', suser_sname(), getdate(), @operation, I.BranchID
    , 'BranchZoneID', OWD.BranchZoneName, NWD.BranchZoneName
from inserted I
left outer join deleted D on I.BranchID = D.BranchID

-- Fetch Branch Zone Names
left join dbo.BranchZone OWD on OWD.BranchZoneID = D.BranchZoneID
left join dbo.BranchZone NWD on NWD.BranchZoneID = I.BranchZoneID

where coalesce(I.BranchZoneID,0) <> coalesce(D.BranchZoneID,0)
and update(BranchZoneID);

如果BranchZoneID 是uniqueidentifer，您将使用：

where coalesce(I.BranchZoneID,'00000000-0000-0000-0000-000000000000') <> coalesce(D.BranchZoneID,'00000000-0000-0000-0000-000000000000')

当使用coalesce以这种方式比较值时，您需要选择一个对数据类型有效但在您的数据中无效的值。