Previous Record

[Sodom]

I created a database which contain a table primary key is a non dublicated date field. I want to enter a new record with a form but at this step i just want to make some calculation with previous record and if the entered data passes my calculation results criteria then i want to let the the new record to transer to the table. The logic is i want to control the balance. Previous day value + production - consumption must be equal to the todays value. User will enter the todays value, consumption and production i want to check it.
Sodom

 

[Chris RR]

At the risk of sounding like a broken record, do NOT store balances in records. Recalculate them when you need them.