Access 2010, the local has a table/T - usage, dosage of user input, the assumption is that 110 , then open the SQL on an inventory record/T - the inventory, find the date of the oldest an inventory record:
Determine if the user dosage is less than or equal to the inventory, direct quit,
If use dosage is greater than the inventory, the surface of the original records to the inventory, the rest of the add a record, until to 0, such as:

Use home use 110, inventory records, each box only 25
110-25-25-25-25-10 until 0
[T - usage] to modify the first after the original record, add 4 more records, wrap/T - the inventory of the fill in, and the records of packing number is filled in inventory to 0,
Is the new use of local records, SQL minus inventory,