How can I incorporate a database query into the submit to database action

[RG]

Hi,

I'm have no real knowledge of coding, but I have managed to make a working
timesheet form using the standard functions of infopath. My form submits the
information to an access database very well. The only thing I want for is
better validation. At present it is possible for a user to make a new form
and submit a duplicate timesheet for a particular person+week. Also it is
possible for a user to submit a timesheet form, make changes to the form (ie
change the date) and re-submit it. The user thinks they then have 2
submitted timesheets, but infopath replaces the first submission with the
second...

I was hoping that SP1 would have a few more controls for non-coders like me
to help me avoid these problems. At present I have just educated the users
how they must work with the form, but I would love to add this
validation/checking into the form.

Short of coders night school, can anyone give me some simple tips / code or
pointers on how I can;

1) when a date+person is selected from my drop-down boxes, the form queries
the database to check that a timesheet with matching date+person does not
exist. This could also be done as part of the submit button function.. but
I'd rather it happened before someone spent 10 minutes filling out the form.

2) Once a timesheet form has been submitted, that it locks the date from
further amendment. I figure this is the best scenario because a user might
save a working copy of the timesheet form between opening a blank one and
submitting it. Even if I choose to close the form on submit, the saved copy
exists and can be re-opened, changed re-submitted etc..

any help would be appreciated.
cheers,
RG

 

[RG]

I've had opportunity to look around the new features of SP1 a bit now and I
think I have part 2 of my question fixed. I managed that by using the submit
with rules features + a boolean record in the form.

I'm still a little confusing with the query database problem (part 1 of my
question). I have tryed adding a query to database connection, but I don't
understand how it functions. I can make the connection, but where do I tell
the form what query to put to the database and what to do based on the
result.?

cheers,
RG