Design Issues - Urgent

[samosa]

I inherited a table that was poorly designed.
No primary key and several duplications.
For instance, each table has id has several values.
I broke the tables into 3 - master table with unique entries, the other 2 tables with duplicate entries.
Now, I know I have to design it with 1:m relationship but the problem I am having is that while the master table has unique values for instance idnum has unique values but idnum has some null values in the other 2 two tables.
Can anyone tell me how I can link these two tables with the master table?
I hope this is not confusing.
thanks in advance!

 

[Shirley]

The only way to solve this problem is to put unique number on the first table and put that unique number on table 2 for all null, any number that you are not currently using. This way you would be able to set up a relationship, but make sure you remember this number, I always use 999, hope this helps.