Use the help from the client, it's pretty useful. It says:
This table is used to handle and store information concerning reservation, item tracking and order tracking.
When handling item tracking in connection with partial posting, the table works in conjunction with the Tracking Specification table.
Data entered in the Item Tracking Lines form by the user is created in a temporary version of the Tracking Specification table and committed to the Reservation Entry and Tracking Specification tables when the form is closed.
Ok so reading that it's not the most useful. In short it's used so that you can make sure certain inventory is used on a certain order. Imagine a scenario where you are buying a part for a customer. You don't want some other salesperson coming in, taking that part, and selling it to someone else. So you need a way to make sure it is used by your customer and your customer only.
But this table is used for different purposes too (not only to reservations). E.g. when you add some lot/serial number to any document or journal line, new entry will be created in this table. It means not just reservations but tracking is done through this table.
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Ok so reading that it's not the most useful. In short it's used so that you can make sure certain inventory is used on a certain order. Imagine a scenario where you are buying a part for a customer. You don't want some other salesperson coming in, taking that part, and selling it to someone else. So you need a way to make sure it is used by your customer and your customer only.
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