Question

I have a non-typed dataset filled with data from user input (no database). There’s no primary key column (my data had no need for primary key so far)! Is there any way to avoid “brute force” if i want to check if new row user is trying to insert already exists in my DataTable? How should i perform that check?

Answer 1

You can manually create unique constraints for your DataTable:

DataTable custTable = custDS.Tables["Customers"];
UniqueConstraint custUnique = new UniqueConstraint(new DataColumn[] 
    {custTable.Columns["CustomerID"], 
    custTable.Columns["CompanyName"]});
custDS.Tables["Customers"].Constraints.Add(custUnique);

For this example, you would get an exception (of type ConstraintException) if you tried to add a row to the table where the CustomerID and CompanyName were duplicates of another row with the same CustomerID and CompanyName.

I would just let the DataTable check these things for you internally – no point reinventing the wheel. As to how it does it (whether it is efficient or not), will have to be an exercise for you.