Entities/Tables that only apply to one db when working with multiple

[dave08]

I need to work with multiple databases, and their tables are different. Currently, all Entities/Tables can be mistakenly used by any database. I was thinking of one solution for us:

class DbOne(private val db: Database): Database by db {
    val oneTable get() = db.sequenceOf(TableOne)
}

but Database isn't an interface nor open, so it can't be derived from... are there any other suggested solutions to this problem?

By the way, this kind of possibility would also be useful for dependency injection... instead of using @Named() (in Micronaut, but also applies to other frameworks), we could inject the right db straight away.

[dmitchell]

We (Cargurus) use annotations @Snowflake, @MySql, @Postgres for this, but other than for auto-verifying Table<> definitions during integration testing, it's mostly for the developer. I'll have to think whether there's a reasonable place (e.g., on the code for innerJoin and its siblings) to ensure that all the tables have the same annotation.

We seldom use Entity<> via the sequenceOf (sometimes via row.toEntity() but not often as our selects are usually not all and just the columns of the from(table))