When using multiple databases one database is known as the default database. We need to do 4 things for entity beans that should only be used on the non-default database(s).

Model constructor

Use the io.ebean.Model constructor that take the string name of the database that should be used. 

...
@DbName("other")
@MappedSuperclass
public abstract class OtherBaseDomain extends Model {

  public OtherBaseDomain() {
    super("other");             // "other" -> database name
  }
  ...
}

...
@DbName("other")
@MappedSuperclass
open class OtherBaseDomain : Model("other") {  // "other" -> database name

 ...

}

All entity beans that extend this model will use the named database when they save() and delete().

@DbName

Put @DbName on a mapped superclass or individual entity beans. This is read by the querybean generator when generating the query beans so that queries for this entity bean type will execute using the named non-default database. 

...
@DbName("other")  // "other" -> database name
@MappedSuperclass
public abstract class OtherBaseDomain extends Model {

  public OtherBaseDomain() {
    super("other");             // "other" -> database name
  }
  ...
}

...
@DbName("other")   // "other" -> database name
@MappedSuperclass
open class OtherBaseDomain : Model("other") {  // "other" -> database name

 ...

}

For all entity beans extending OtherBaseDomain their query beans will now default to using the named database.

Finder constructor

If using io.ebean.Finder we similarly use the constructor that takes the string name of the database that should be used. 

...
public class CustomerFinder extends Finder {

  public CustomerFinder() {
    super("other");             // "other" -> database name
  }
  ...
}

...
open class CustomerFinder : Finder("other") {  // "other" -> database name
 ...
}

Now using methods on CustomerFinder will default to using the named database.

Register entity types

We also need to register some entity types to the default database and some entity types to the other non default database(s).

Note that from Ebean version 12.2.1 the querybean generator will generate code to register the entity bean types to the appropriate database.

Create an implementation of ServerConfigProvider that registers the entity beans with the appropriate database based on the name. 

public class RegisterDomainBeans implements ServerConfigProvider {

  private static final String OTHER = "other";

  private static final String DB = "db";

  @Override
  public void apply(ServerConfig serverConfig) {

      log.debug("register beans for {}", serverConfig.getName());
      if (DB.equals(serverConfig.getName())) {
        // the default database
        serverConfig.addClass(DCustomer.class);
        serverConfig.addClass(DOrder.class);
        serverConfig.addClass(DProduct.class);
        ...

      } else if (OTHER.equals(serverConfig.getName())) {
        // second OTHER database
        serverConfig.setDefaultServer(false);
        serverConfig.addClass(OSales.class);
        serverConfig.addClass(OMarket.class);
        ...

      }
  }
}

Add a service loader src/main/resources/META-INF/services/io.ebean.config.ServerConfigProvider file to specify our ServerConfigProvider implementation (e.g. RegisterDomainBeans).