Hi all, I am trying to make a `User` model object to be inserted into a database. I want to insert t...

# getting-started

[Justin Xu]

Hi all, I am trying to make a User model object to be inserted into a database. I want to insert these into various databases using a Repository pattern, but the User has an id field that is generated differently for each database I use. Is there a way to defer the definition of the id type and a generateId() function until the actual creation of the User object in Kotlin? Thanks

[gildor]

No, it’s not possible direclty, but you alway can create a new instance of User object with new database id, and maybe on insert make id nullable (or some default value)
Don’t say that it’s the best, but in general ORM approach is bad IMO and such issues as one you described haunt apps with ORMs forever

[Casey Brooks]

If you're able to change the record schema, I've recently been favoring UUIDs created and assigned in the application code instead of relying on anything generated by the database/ORM. It makes situations like this so much easier to work with. Java's got a built-in UUID class, or this library works well for multiplatform https://github.com/benasher44/uuid

[Justin Xu]

Thanks for the feedback 😄 Nice to see I'm not the only one with headache from this issue. I'll look into UUID and other ways to avoid using ORM

[gildor]

Uuid is not the best solution for indexes, but depends on your scale

[Matteo Mirk]

there are many variations of implementing unique identifiers, UUID just happens to be the most popular. Depending on your needs you may want to try out alternatives, for example if you need identifiers that are shorter, human-readable/memorizable, or sortable (ie ULID), etc. For example take a look here: https://github.com/sw-yx/uuid-list

Here are some analysis on UUID:
https://dzone.com/articles/uuid-as-primary-keys-how-to-do-it-right
https://www.softwareatscale.dev/p/guids-are-not-enough