In MRP, requirement quantities are maintained in the system as planned independent requirements, customer requirements, dependent requirements, material reservations as well as forecast requirements. The system checks every exact requirement and every forecast requirement to determine whether they are covered by available warehouse stock and/or receipts (purchase orders, firmed procurement proposals, production orders, and so on).

You have set an MRP type in the MRP Type field in the material master (View MRP 1) to MRP for the material.

Available stock is calculated as follows:

A shortage occurs if available stock is negative, that is, the requirement quantities are greater than expected receipts and stock quantity.

The system specifies the date of the issue (for example, customer requirement, planned independent requirement, reservation, forecast requirement) as the requirements date.