Constraints check: TRY/CATCH vs Exists()

Question

I have a table with unique constraint on it:

create table dbo.MyTab
(
    MyTabID int primary key identity,
    SomeValue nvarchar(50)
);
Create Unique Index          


        

Answer 1

Option - 3

Begin Try
    SET XACT_ABORT ON
    Begin Tran
        IF NOT EXISTS (Select 1 From MyTab Where SomeValue = @someValue)
        Begin
            Insert Into MyTab(SomeValue) Values ('aaa');
        End
    Commit Tran
End Try

begin Catch
    Rollback Tran
End Catch