Cannot edit a record error

Hello guys ,

Cannot edit a record in  (PurchTable).
The values displayed in the form are not current, so an update or deletion cannot be made. To view the current values, on the Command menu, click Restore or press CTRL+F5.

I am acrosses this problem in frequently.I search on internet it says I should write update and reread the table.Is it true?

Have you ever seen this problem?Do you know the main reason about this problem and How should i solve it?