Hi I am using DBswing components

[Gita21]

Hi

I am using DBswing components.

>> Course
>> ------
>> CourseID(PK)
>> CourseStartDate(PK)
>>
>> Registration
>> ----------
>> customerID (PK)
>> courseID(PK)
>> courseStartDate(PK)
>>
A person cannot register for a course where the courseStartDate is same as the courseStartDate for a course already registered by that customer.

I'm using these queryDataSets
Select * from person
Select * from course
Select * from registration where customerID =: personID (master link table person)

When I register a customer, I enter the courseID and courseStartdate.
When click save - I want to check that the courseStartDate entered
is not the same as a startDate already saved in the registration
table of that particular customer.
Because can't have a customer taking 2 courses at the same date.

I don't know how to go through the queryDataSet and check it.
Help pliz