I'm building an electronic parts database in D7 and want to create a custom "part" entity with bundles for resistors, capacitors, etc.
I also need to autocreate an atomic serial part number common to all bundles, i.e no separate part numbering system per bundle. I was going to use the Serial module but it only works with nodes. In D6 I did everything in nodes for a similar application and just used the NID, but this parts DB really wants a cleaner solution using entities. I'd like to use the entity ID as the serial part number but only if it's unique per custom entity type.
Question is: Does each custom entity type I create have its own set of entity IDs or is it like in D6 with nodes where NIDs apply across all content types?