Need a way to intercept only a Duplicate key exception in MSSQL

Let's imagine that you have got a unique index constraint violation in your MSSQL 2008 database like this: ``` Violation of PRIMARY KEY constraint 'PK_ManufacturerCode'. Cannot insert duplicate key in object 'dbo.ManufacturerCode'. The duplicate key value is (8410179) ``` Currently I am handling this exception by a global exception handler in a thick client (written in Delphi 6 using ADO, but it does not matter, I plan do use C#.NET in a future) and the exception message is appended to a log box. But I want to handle this specific duplicate key exception personally and display an appropriate error message in a client using thick client's own text. I could parse the error message for match, but won't do this out of two reasons: - This is not a right way to do the thing - it is better to rely on some error codes; - The thick client is intended to use variety of MSSQL server versions in diverse languages which may have different error texts It does not cheer me up to do the job with RETURNs with custom exit codes or constantly calling a special stored procedure to check for duplicates.