Inserting 2 Foreign Keys in a table in SQL Server - sql-server

Question

I have the following 3 tables. They are related:
CREATE TABLE [MemberDetails]
(
[MemberID] int identity (1000,1) NOT NULL UNIQUE,
[MName] varchar(100) NOT NULL,
[MSurname] varchar(100) NOT NULL,
[MPhone] varchar(20) NOT NULL UNIQUE,
[MEmail] varchar(200) NOT NULL UNIQUE,
[MAddress] varchar(250) NOT NULL,
[MActive] char (1) NOT NULL CHECK (MActive IN ('Y','N')) DEFAULT 'Y',
[MUpdateDate] Date NOT NULL DEFAULT GETDATE(),
[MPhoto] Image NOT NULL,
[MDid] int NULL UNIQUE,
[MTid] int NULL UNIQUE,
PRIMARY KEY ([MemberID]),
FOREIGN KEY (MDid) REFERENCES [MembershipDetails] ([MDid])
ON DELETE SET NULL
ON UPDATE CASCADE,
FOREIGN KEY (MTid) REFERENCES [MarketingTarget] ([MTid])
ON DELETE SET NULL
ON UPDATE CASCADE
);
CREATE TABLE [MarketingTarget]
(
[MTid] int identity (5000,1) NOT NULL UNIQUE,
[MDOB] date NOT NULL,
[MSex] char NOT NULL CHECK (MSex IN ('M','F')) DEFAULT 'M',
PRIMARY KEY ([MTid]),
);
CREATE TABLE [MembershipDetails]
(
[MDid] int identity (2000,1) NOT NULL UNIQUE,
[MType] varchar(10) NOT NULL CHECK (MType IN ('Monthly', 'Quaterly', 'Yearly')) DEFAULT 'Monthly',
[JoinDate] Date NOT NULL DEFAULT GETDATE(),
[ExpiryDate] Date NULL,
[MsUpdateDate] Date DEFAULT GETDATE(),
PRIMARY KEY ([MDid])
);
I would like to know if it's possible to insert the FKs automatically into the MemberDetails table from the other two tables? I am trying to write the Stored Procedures.
I was checking the Scope_Identity which can get the last identity generated but I am not sure how to use it properly.
Any suggestions would be much appreciate it.

Answer 1

Here is an example (table has been shortened): Since both IDENTITY values are required, I'd save them into a variable and then insert together into MemberDetail.
I would recommend to have a transaction for this operation. And have a look at TRY..CATCH. Depending on your situation you might want to check XACT_STATE().
https://learn.microsoft.com/en-us/sql/t-sql/language-elements/try-catch-transact-sql?view=sql-server-ver15
and there are examples using a trigger
https://learn.microsoft.com/en-us/sql/t-sql/functions/scope-identity-transact-sql?view=sql-server-ver15
CREATE TABLE [_TEST_MemberDetails] (
[MemberID] int identity (1000,1) NOT NULL UNIQUE,
[MDid] int NULL UNIQUE,
[MTid] int NULL UNIQUE,
PRIMARY KEY ([MemberID]),
FOREIGN KEY (MDid) REFERENCES [_TEST_MembershipDetails] ([MDid]) ON DELETE SET NULL
ON UPDATE CASCADE,
FOREIGN KEY (MTid) REFERENCES [_TEST_MarketingTarget] ([MTid]) ON DELETE SET NULL
ON UPDATE CASCADE
);
CREATE TABLE [_TEST_MarketingTarget] (
[MTid] int identity (5000,1) NOT NULL UNIQUE,
[MDOB] date NOT NULL,
[MSex] char NOT NULL CHECK (MSex IN ('M','F')) DEFAULT 'M',
PRIMARY KEY ([MTid]),
);
CREATE TABLE [_TEST_MembershipDetails] (
[MDid] int identity (2000,1) NOT NULL UNIQUE,
[MType] varchar(10) NOT NULL CHECK (MType IN ('Monthly','Quaterly','Yearly')) DEFAULT 'Monthly',
[JoinDate] Date NOT NULL DEFAULT GETDATE(),
[ExpiryDate] Date NULL,
[MsUpdateDate] Date DEFAULT GETDATE(),
PRIMARY KEY ([MDid])
);
-- SP CODE START HERE
SET XACT_ABORT ON;
BEGIN TRY
BEGIN TRANSACTION
DECLARE #MTID int = 0, #MDID int = 0
INSERT INTO _TEST_MarketingTarget ([MDOB], [MSex])
VALUES ('Jan 1, 2020', 'M')
SELECT #MTID = SCOPE_IDENTITY()
INSERT INTO [_TEST_MembershipDetails] ([MType], [JoinDate], [ExpiryDate], [MsUpdateDate])
VALUES (DEFAULT, DEFAULT, 'Jan 1, 2020', DEFAULT)
SELECT #MDID = SCOPE_IDENTITY()
INSERT INTO [_TEST_MemberDetails] (Mdid, MTid)
SELECT #MDID, #MTID
COMMIT TRANSACTION
END TRY
BEGIN CATCH
IF ##TRANCOUNT <> 0 ROLLBACK TRANSACTION
END CATCH
go