Question

I have two SQL tables, each with a compound key made of three different integer fields. I have added the code as follows to add a record to Table1.

try
{
    Table1 newRow = new Table1
    {
        DomainID = domainID,
        ConfigurationID = configID,
        ReasonID = reasonID
    };

    data.Table1.InsertOnSubmit(newRow);
    data.SubmitChanges();
}
catch(DuplicateKeyException)
{
    // Message to user about no duplicates allowed.
}

This works exactly how I have planned and catches an exception if the user is trying to add a duplicate row and I can show them a message etc. All is fine. However, the code I have for inserting to Table2 (which is almost identical, on a different Page using a different DataContext however),

try
{
    Table2 newRow = new Table2
    {
        DomainID = domainID,
        ConfigurationID = configID,
        DirectionID = directionID
    };

    data.Table2.InsertOnSubmit(newRow);
    data.SubmitChanges();
}
catch(DuplicateKeyException)
{
    // Message to user about no duplicates allowed.
}    

does not throw a DuplicateKeyException but a SqlException. Not too much of a big-deal as I can still test

e.Number = 2627

on the caught SqlException but I’m just confused as to why it is working differently!?

Answer 1

There must be a problem with the definition of your table 2. Specifically with the primary key column on it. Maybe it has a Unique Constraint and that’s why it throws an exception, but it is not certainly its primary key.