How to modeling a leasing system ER?
I want to setup a leasing system for 14 items by filemaker. After made a contract, Customers will pick some of them in different times and return them gradually. In returning, some of items need be repaired and some of them must be discarded. Meanwhile, this system can help me control the inventory. The key problem for me is how to model the ER of this system. I think the “Timestamp” may be the primary key because the leasing, returning, repairing and discarding are all related to timestamp, but how to deal with inventory? So, I’m very appreciate that if you could tell me how to construct the ER, and the value list included. Thanks!
The Timestamp cannot be a primary key. A primary key serves as the unique identifier for all records in a given table. You cannot guarantee that a timestamp value will always be unique.Auto-entered serial numbers into number fields and auto-entered text from the Get (UUID) function are your best options for primary keys in FileMaker databases.