BEF3TFm0

1CREATE TABLE dbo.Customer
2(
3    RowId bigint IDENTITY(1,1) NOT NULL,
4    CustomerId guid NOT NULL,
5    Name varchar(255) NOT NULL,
6    CONSTRAINT PK_RowId PRIMARY KEY CLUSTERED([RowId] ASC)
7)
8create unique nonclustered index [UN_CustomerId] ON [dbo].[Customer] ([CustomerId] ASC)
9	
10IF NOT EXISTS
11(
12    SELECT * 
13    FROM dbo.Customer WITH (UPDLOCK, SERIALIZABLE) 
14    WHERE CustomerID = @CustomerId
15)
16BEGIN
17    INSERT INTO dbo.Customer(CustomerId, Name) VALUES (@CustomerId, @Name)
18    SELECT @CustomerId
19END
20ELSE
21BEGIN
22    SELECT CustomerId FROM dbo.Customer WHERE Name = @Name
23END
24	
25BEGIN TRY
26    INSERT INTO dbo.Customer(CustomerId, Name) VALUES (@CustomerId, @Name)
27    SELECT @CustomerId
28END TRY
29BEGIN CATCH
30    SELECT CustomerId FROM dbo.Customer WHERE Name = @Name
31END CATCH