如何使用anorm处理未分配的ID？

Question

Anorm has the special type anorm.Pk for typed primary keys (and its subclass anorm.NotAssigned ). This allows to assign a NotAssigned value if the database is responsible for generating the relevant key.

Is there an equivalent concept for foreign keys? I'm using type Long at the moment. However, if the foreign key is not yet known, I will have to assign a null value or replace the type by an Option[Long] . This feels like it's not the way it's meant to be done, though.

Answer 1

Anorm doesn't offer functionality around relations.

Take your FK out of your model, but accept FKs as arguments to your CRUD, eg for creating a "Contrived" that belongs to a user:

def create(c: Contrived, userId: Long)
  DB.withConnection { implicit connection =>
  val id = SQL("""
      insert into c
      (first, second, login_id)
      values
      ({first}, {second}, {login_id})
      """).on(
    'first -> c.first,
    'second -> c.second,
    'login_id -> userId

...etc