SQL Server : INSTEAD OF INSERT trigger & Identity

问题:

I've been banging my head against a wall for the better part of a week. I've been studying SQL (T-SQL) for a few weeks now, and I've hit a snag.

I'm building a database that will store client data for a company. The tables in the DB are normalized, so I have multiple tables that are linked together using Foreign Key Constraints.

Microsoft Access will be used to interface with the database (as a frontend). To make things simpler, I created a view that joins all the required tables together so that end-users can query information without hassle.

The problem I've run into involves INSERTING information into this view. From my understanding, since I have multiple tables in my view, I have to use a trigger with an INSTEAD OF INSERT statement. I've created the trigger; however, I'm unsure how to work with the ID columns in the tables (these act as keys).

I have a MemberBasicInformation table that contains the client's DOB, Name, Gender, etc AND their MemberID. This ID is an IDENTITY column in the table, so it is generated automatically. The problem that I'm running into is that because the identity is automatically generated, I'm unable to grab the identity value that is generated after the insert into the MemberBasicInformation table and insert it into the other related tables. When I attempt to do so, I end up with a Foreign Key constraint violations.

I've tried using @@Identity and Scope_Identity() to no avail. I've listed my view and trigger to give you an idea of how things are set up. I would greatly appreciate if someone could point me in the right direction. I'm truly at a loss.

MEMBER view:

CREATE VIEW [dbo].[Member]
AS
    SELECT        
        dbo.MemberBasic.MemberId, dbo.MemberBasic.FirstName, 
        dbo.MemberBasic.MiddleInitial, dbo.MemberBasic.LastName, 
        dbo.MemberBasic.FullName, dbo.MemberBasic.DateOfBirth, 
        dbo.Gender.Name AS Gender, dbo.MemberBasic.Address, 
        dbo.MemberBasic.Address2, dbo.MemberBasic.City, 
        dbo.MemberBasic.State, dbo.MemberBasic.ZipCode, 
        dbo.MemberBasic.PhoneNumber, 
        dbo.MemberBasic.SocialSecurityNumber, 
        dbo.MemberBasic.DriversLicense, 
        dbo.MemberBasic.EmployerIdentificationNumber, 
        dbo.MemberBasic.Notes, 
        dbo.FieldRep.Name AS FieldRepName, 
        dbo.MemberDetail.DateAssigned AS FieldRepDateAssigned, 
        dbo.MemberDetail.CPReceivedOn, dbo.MemberDetail.CredentialedOn, 
        dbo.MemberEligibility.IsActive, dbo.ICO.Name AS ICO, 
        dbo.MemberEligibility.StartDate AS EligibilityStartDate, 
        dbo.MemberEligibility.EndDate AS EligibilityEndDate, 
        dbo.MemberWorkerCompDetail.ExpirationDate AS WorkerCompExpirationDate, 
        dbo.MemberWorkerCompDetail.AuditDate AS WorkerCompAuditDate, 
        dbo.WorkerCompTier.Name AS WorkerCompTier, 
        dbo.MemberAttachment.AttachmentId, 
        dbo.MemberAttachment.Data AS AttachmentData
    FROM            
        dbo.MemberAttachment 
    INNER JOIN
        dbo.MemberBasic ON dbo.MemberAttachment.MemberId = dbo.MemberBasic.MemberId 
    INNER JOIN
        dbo.MemberCaregiverAssignment ON dbo.MemberAttachment.MemberId = dbo.MemberCaregiverAssignment.MemberId 
    INNER JOIN
        dbo.MemberDetail ON dbo.MemberBasic.MemberId = dbo.MemberDetail.MemberId 
    INNER JOIN
        dbo.MemberEligibility ON dbo.MemberAttachment.MemberId = dbo.MemberEligibility.MemberId 
    INNER JOIN
        dbo.MemberWorkerCompDetail ON dbo.MemberAttachment.MemberId = dbo.MemberWorkerCompDetail.MemberId 
    INNER JOIN
        dbo.Gender ON dbo.MemberBasic.GenderId = dbo.Gender.GenderId 
    INNER JOIN
        dbo.FieldRep ON dbo.MemberDetail.FieldRepId = dbo.FieldRep.FieldRepId 
    INNER JOIN
        dbo.ICO ON dbo.MemberEligibility.ICOId = dbo.ICO.ICOId 
    INNER JOIN
        dbo.WorkerCompTier ON dbo.MemberWorkerCompDetail.TierId = dbo.WorkerCompTier.TierId
GO

MEMBER trigger:

ALTER TRIGGER [dbo].[InsertNewMember] 
ON [dbo].[Member] 
INSTEAD OF INSERT
AS 
BEGIN
    SET NOCOUNT ON;

    INSERT INTO MemberBasic (FirstName, MiddleInitial, LastName, GenderId, DateOfBirth, Address, Address2, City, State, ZipCode, PhoneNumber, SocialSecurityNumber, DriversLicense, EmployerIdentificationNumber, Notes)
        SELECT 
            FirstName, MiddleInitial, LastName, GenderId, DateOfBirth, 
            Address, Address2, City, State, ZipCode, PhoneNumber, 
            SocialSecurityNumber, DriversLicense, 
            EmployerIdentificationNumber, Notes 
        FROM 
            inserted
        INNER JOIN
            Gender ON Gender.Name = Gender; 

    INSERT INTO MemberDetail (MemberId, FieldRepId, DateAssigned, CPReceivedOn, CredentialedOn)
        SELECT 
            MemberId, FieldRep.FieldRepId, FieldRepDateAssigned, 
            CPReceivedOn, CredentialedOn
        FROM 
            inserted
        INNER JOIN
            FieldRep ON FieldRep.Name = FieldRepName;

    INSERT INTO MemberEligibility (MemberId, ICOId, StartDate, EndDate)
        SELECT 
            MemberId, ICOId, EligibilityStartDate, EligibilityEndDate 
        FROM 
            inserted
        INNER JOIN
            ICO ON ICO.Name = ICO;

    INSERT INTO MemberWorkerCompDetail (MemberId, AuditDate, ExpirationDate, TierId)
        SELECT 
            MemberId, WorkerCompAuditDate, WorkerCompExpirationDate, TierId
        FROM 
            inserted
        INNER JOIN
            WorkerCompTier ON WorkerCompTier.Name = WorkerCompTier;

    INSERT INTO MemberAttachment (MemberId, Data)
        SELECT MemberId, AttachmentData
        FROM Member
END

回答1:

You can do this by using a table variable to hold the newly inserted IDs and all of the data that you're going to insert into the other tables. You need to do this because there's no way from just the first INSERTs data to join back to inserted in such a manner that you can match up the IDENTITY values with the rows that caused them to be generated.

We also have to abuse MERGE since INSERT doesn't let you include anything other than the target table in its OUTPUT clause.

I'm doing this on a toy example but hopefully you can see how to write it for your full table structures.

First, some tables:

create table dbo.Core (
    ID int IDENTITY(-71,3) not null,
    A varchar(10) not null,
    constraint PK_Core PRIMARY KEY (ID)
)
go
create table dbo.Child1 (
    ID int IDENTITY(-42,19) not null,
    ParentID int not null,
    B varchar(10) not null,
    constraint PK_Child1 PRIMARY KEY (ID),
    constraint FK_Child1_Core FOREIGN KEY (ParentID) references Core(ID)
)
go
create table dbo.Child2 (
    ID int IDENTITY(-42,19) not null,
    ParentID int not null,
    C varchar(10) not null,
    constraint PK_Child2 PRIMARY KEY (ID),
    constraint FK_Child2_Core FOREIGN KEY (ParentID) references Core(ID)
)
go

And the view:

create view dbo.Together
with schemabinding
as
    select
        c.ID,
        c.A,
        c1.B,
        c2.C
    from
        dbo.Core c
            inner join
        dbo.Child1 c1
            on
                c.ID = c1.ParentID
            inner join
        dbo.Child2 c2
            on
                c.ID = c2.ParentID
go

And finally the trigger:

create trigger Together_T_I
on dbo.Together
instead of insert
as
    set nocount on
    declare @tmp table (ID int not null, B varchar(10) not null, C varchar(10) not null);

    merge into dbo.Core c
    using inserted i
    on
        c.ID = i.ID
    when not matched then insert (A) values (i.A)
    output
        inserted.ID /* NB - This is the output clauses inserted,
                    not the trigger's inserted so this is now populated */
        ,i.B,
        i.C
    into @tmp;

    insert into dbo.Child1(ParentID,B)
    select ID,B
    from @tmp

    insert into dbo.Child2(ParentID,C)
    select ID,C
    from @tmp

(And I would keep something like that comment in there since statements inside triggers that include OUTPUT clauses tend to be quite confusing since there are two inserted tables in play)

(It's also noteworthy that it doesn't really matter what you put in the ON clause of the MERGE, so long as you're sure that it will fail to make a match. You may prefer to have, say, just 1=0 if you think it makes it clearer. I just went cute on the fact that the trigger's inserted.ID will be NULL)

And now we do our insert:

insert into dbo.Together(A,B,C) values ('aaa','bbb','ccc')
go
select * from dbo.Together

And get the result:

ID          A          B          C
----------- ---------- ---------- ----------
-71         aaa        bbb        ccc

回答2:

Here is answer to your question "Getting Identity values to use as FK in an INSTEAD OF trigger"

https://dba.stackexchange.com/questions/34258/getting-identity-values-to-use-as-fk-in-an-instead-of-trigger