Business scene:
When the business department creates a reservation, it is reserved for the existing inventory, that is, the reservation must be based on the fact that the inventory cannot exceed the existing inventory, so the reservation needs to be controlled.
First check the inventory, and then create a reservation that exceeds the inventory quantity, a yellow light will be reported, but the Enter can be skipped. Message number M7181, can it be controlled by controlling the message number?
Test reserved quantity 1002 is greater than non-current stock quantity 1001
Change the message number or the yellow light warning, 
cancel it, so this message number M7181 is not customizable
Then the number of created reservation orders can exceed the inventory quantity, but this is not normal, it must be controlled, SPRO-material management-inventory management and actual inventory-reservation-set dynamic customer user check
Check the stock quantity first
while reservation creation is in progress,
It is possible to create 1000, but not 1001. From the inventory point of view, 2 have been reserved, and the total inventory is 1001, so the availability is 999. Here, 1000 can be reserved. Personally, I think it should be 1 outstanding PO. counted.
Then this function realizes the control that the reserved quantity cannot exceed the inventory quantity.
A reservation can be created when the stock is not enough.
Reservations cannot be created when B stock is insufficient.