Bulk inert to parent children tables - sql

Question

I have the following three tables (each RobotPart has exactly one arm and one leg). I have a large number of {arm, leg} pairs need to be inserted. Any new combinations of arm and leg will create a new entry in RobotPart. Any existing combination will not be inserted. No updates are needed for either parent or children. I need preserve the identity columns. Any efficient ways to accomplish this in SQL?
CREATE TABLE [dbo].[Arm](
[Id] [int] IDENTITY(1,1) NOT NULL,
[Model] [varchar](20) NULL,
CONSTRAINT [PK_dbo.Arm] PRIMARY KEY CLUSTERED
(
[Id] ASC
)
) ON [PRIMARY]
CREATE TABLE [dbo].[Leg](
[Id] [int] IDENTITY(1,1) NOT NULL,
[Model] [varchar](10) NULL,
CONSTRAINT [PK_dbo.Leg] PRIMARY KEY CLUSTERED
(
[Id] ASC
)
) ON [PRIMARY]
CREATE TABLE [dbo].[RobotPart](
[Id] [int] IDENTITY(1,1) NOT NULL,
[Name] [varchar](20) NOT NULL,
[ArmId] [int] NOT NULL,
[LegId] [int] NOT NULL,
CONSTRAINT [PK_dbo.RobotPart] PRIMARY KEY CLUSTERED
(
[Id] ASC
)
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[RobotPart] WITH CHECK ADD CONSTRAINT [FK_dbo.RobotPart_dbo.Arm_ArmId] FOREIGN KEY([ArmId])
REFERENCES [dbo].[Arm] ([Id])
GO
ALTER TABLE [dbo].[RobotPart] WITH CHECK ADD CONSTRAINT [FK_dbo.RobotPart_dbo.Leg_LegId] FOREIGN KEY([LegId])
REFERENCES [dbo].[Leg] ([Id])
GO

Answer 1

Step 1: Insert new arms and legs using a LEFT OUTER JOINs from your source table to the arms and legs table, respectively. (a separate insert statement for each table)
Step 2: Insert the new combinations using an inner join from your source table to arms and legs and a left outer join from the your source table to the RobotPart table.

Answer 2

Here is my initial try on it using MERGE. Not sure how this compare to Lmu92 proposed.
CREATE TYPE [dbo].[RobotPart_udtt] AS TABLE(
[Arm] [varchar](20) NOT NULL,
[Leg] [varchar](10) NOT NULL,
[Name] [varchar](20) NOT NULL
)
GO
CREATE PROCEDURE dbo.[prc_Component_Create]
#robotParts [RobotPart_udtt] READONLY
AS
BEGIN
SET NOCOUNT ON;
DECLARE #messageId INT
DECLARE #status INT
MERGE [Arm] AS TARGET
USING (
SELECT
tR.arm AS Model
FROM #robotParts AS tR
) AS SOURCE
ON TARGET.Model = SOURCE.Model
WHEN NOT MATCHED THEN
INSERT
(
Model
)
VALUES
(
SOURCE.Model
);
MERGE [Leg] AS TARGET
USING (
SELECT
tR.leg AS Model
FROM #robotParts AS tR
) AS SOURCE
ON TARGET.Model = SOURCE.Model
WHEN NOT MATCHED THEN
INSERT
(
Model
)
VALUES
(
SOURCE.Model
);
WITH NewParts (ArmId, LegId, Name)
AS
(
SELECT tA.Id
, tL.Id
, tR.Name
FROM #robotParts AS tR
INNER JOIN [Arm] AS tA
ON tR.Arm = tA.Model
INNER JOIN [Leg] AS tL
ON tR.Leg = tL.Model
)
INSERT INTO RobotPart (Name, ArmId, LegId)
SELECT tN.Name
, tN.ArmId
, tN.LegId
FROM NewParts AS tN
LEFT JOIN RobotPart AS tR
ON tR.ArmId = tN.ArmId
AND tR.LegId = tN.LegId
WHERE tR.ArmId IS NULL AND tR.LegId IS NULL
END