Question

If I were to have 2 tables, call them TableA and TableB. TableB contains a foreign key which refers to TableA. I now need to add data to both TableA and TableB for a given scenario. To do this I first have to insert data in TableA then find and retrieve TableA’s last inserted primary key and use it as the foreign key value in TableB. I then insert values in TableB. This seems lika a bit to much of work just to insert 1 set of data. How else can I achieve this? If possible please provide me with SQL statements for SQL Server 2005.

Answer 1

That sounds about right. Note that you can use SCOPE_IDENTITY() on a per-row basis, or you can do set-based operations if you use the INSERT/OUTPUT syntax, and then join the the set of output from the first insert – for example, here we only have 1 INSERT (each) into the “real” tables:

/*DROP TABLE STAGE_A
DROP TABLE STAGE_B
DROP TABLE B
DROP TABLE A*/
SET NOCOUNT ON

CREATE TABLE STAGE_A (
    CustomerKey varchar(10),
    Name varchar(100))
CREATE TABLE STAGE_B (
    CustomerKey varchar(10),
    OrderNumber varchar(100))

CREATE TABLE A (
    Id int NOT NULL IDENTITY(51,1) PRIMARY KEY,
    CustomerKey varchar(10),
    Name varchar(100))
CREATE TABLE B (
    Id int NOT NULL IDENTITY(1123,1) PRIMARY KEY,
    CustomerId int,
    OrderNumber varchar(100))

ALTER TABLE B ADD FOREIGN KEY (CustomerId) REFERENCES A(Id);

INSERT STAGE_A VALUES ('foo', 'Foo Corp')
INSERT STAGE_A VALUES ('bar', 'Bar Industries')
INSERT STAGE_B VALUES ('foo', '12345')
INSERT STAGE_B VALUES ('foo', '23456')
INSERT STAGE_B VALUES ('bar', '34567')

DECLARE @CustMap TABLE (CustomerKey varchar(10), Id int NOT NULL)

INSERT A (CustomerKey, Name)
OUTPUT INSERTED.CustomerKey,INSERTED.Id INTO @CustMap
SELECT CustomerKey, Name
FROM STAGE_A

INSERT B (CustomerId, OrderNumber)
SELECT map.Id, b.OrderNumber
FROM STAGE_B b
INNER JOIN @CustMap map ON map.CustomerKey = b.CustomerKey

SELECT * FROM A
SELECT * FROM B