How to use a compund Primary Key?

[Schlingel]

Hi
I have a little problem. I have a database with two tables: Nachweis and Entschuldigungen. In the first one u can add the records of what u have done for every day, the second one is for the days when u were absent.
I need to let the user to add in the second table only records which are NOT included in the first one. So if i have records for 10.10.2006 in the first table, i can't add records for 10.10.2006 in the second one. I wanna do it with help of the Compound Primary Key. But i don't even know where i should start.
Any help will be appreciated
Thanks in advance

 

[b0gdan]

Hi

When you will add records in the second table you will need to use Dlookup function to verify if there exist in the first table.Example: Dlookup("[newdata]","[table1]","[newdata='" & Me.txt.....&"'")
See how Dlookup works!!
And if your compound key contains lets say 2 elements you can use Dlookup to verify that like this: Dlookup("[newdata]","[table1]","[newdata='" & element 1 &"' & "AND" & '" & element 2 &"'")

 

[Schlingel]

Thanks for ur reply, but Access writes me a syntax error in Criteria
items = DLookup("[Datum]", "Entschuldigung", "[Datum]= 10.10.2006")

 

[b0gdan]

Try this:
items = DLookup("[Datum]", "Entschuldigung", "[Datum]=#" & Month(10.10.2006) & "/" & Day(10.10.2006) & "/" & Year(10.10.2006) & "#"

in dlookup you have: for text '"....."', for number only "...." and for date with ##

 

[Schlingel]

Thanks so much.
I have found out how to do it best. Here is the hyperlink to the page:
http://www.access-programmers.co.uk/forums/showthread.php?t=117021&page=2

 

[Pat Hartman]

The real problem is that you are using two tables when you should be using one.