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Is it possible create an entity class from a table with a composite primary key?
It seems the API forces the IdTable derived objects have got only one key column. Is there any equivalent to the JPA's EmbeddedId and IdClass annotations?
Hi, @jorginius . It's not possible at the moment, but I hope we can fix it in a while. Do you have any experience with EmbeddedId or IdClass approach? Or maybe you can share your vision how it might be implemented to be mostly useful?
Hi, @Tapac .
I commented about the EmbeededId (and Embeddable) annotation because I think it could be the less disruptive approach (one object key, one parameter), but I'm not sure if mimicking JPA is the right way on this point:
@Embeddable
public class UserToRoleKey {
@Column(nullable = false)
private String code;
@Column(nullable = false)
private String username;
// ...
}
@Entity
public class UserToRole {
@EmbeddedId
private UserToRoleKey key;
// ...
}
// ...
UserToRoleKey key = new UserToRoleKey();
key.setCode("USER");
key.setUsername("test);
entityManager.find(UserToRole.class, key);
"Raw" Table objects can hold a composite key easily:
internal object UsersToRoles : Table("users_roles") {
val code = reference("code", Roles.code).primaryKey()
val username = reference("username", Users.username).primaryKey()
}
Perhaps the ideal API :-) has a EntityClass which works with Table objects (creating EntityId from primaryId fields automatically) or IdTable is deprecated/superseded by the "vanilla" Table, i don't know.
It is my only problem in current project! Please lead me with a workaround at least!
@kamyar1979 , sad, but there is not workaround atm, because entityId is a hardly coupled with a single column instance. We have uncompleted refactoring with this feature support, but it requires a lot of testing before release, so we can't give any ETA :(
A very ugly and <8 bit int-specific work around I've been using:
object dgmtypeeffects: IntIdTable(columnName = "typeID\" << 8 | \"effectID") {
val typeID = integer("typeID").primaryKey()
val effectID = integer("effectID").primaryKey()
val isDefault = bool("isDefault")
val effect = reference("effectID", dgmeffects)
val type = reference("typeID", invtypes)
fun idFromPKs(typeID: Int, effectID: Int): Int {
return typeID shl 8 or effectID
}
fun findFromPKs(typeID: Int, effectID: Int): dgmtypeeffect? {
return dgmtypeeffect.findById(idFromPKs(typeID, effectID))
}
}
class dgmtypeeffect(id: EntityID<Int>): IntEntity(id) {
companion object: IntEntityClass<dgmtypeeffect>(dgmtypeeffects)
var typeID by dgmtypeeffects.typeID
var effectID by dgmtypeeffects.effectID
var isDefault by dgmtypeeffects.isDefault
val effect by dgmeffect referencedOn dgmtypeeffects.effect
val type by invtype referencedOn dgmtypeeffects.type
}
findByPKs returns the correct object, and accessing these by references in other tables works, I can't say more than that.
The shift could be adjusted, and more values could be added.
seems there is a solution here: https://github.com/JetBrains/Exposed/issues/239
This issue was created 4 years ago, how is this not fixed yet?
You should ask for your money back
I believe that I found a solution: https://stackoverflow.com/questions/57633755/kotlin-exposed-entity-for-table-with-no-identity-column
@Tapac is there any README about this on-going feature that the community can read and try to contribute?
Bumping because this is ridicolous, I just made an IntIdTable now without using the Id ever.
