I have two tables .One is the main table and other sub- Table.
The main table contain many information very one has Idno.
And sub-table contain personal information related the holder idno.
What I want when I open main form special in Idno field I want the sub-table show his information
When I open main table and I go to idno 10 the sub-table must open and show his personal information.
Create a form based on your main table, then insert a sub-form based on the sub-table. When you use the wizard, Access will suggest the linking criteria between the two, and this should be your ID number.