Consider the situation where the owned entity type can also be owned by another parent entity type. Do you put foreign key references in the owned table to both parent tables? What if you have three parent types? It just doesn’t scale to large designs. A join-table decouples the join, so that the owned table … Read more
From the comments I see you’ve found the answer. But the SQLAlchemy documentation is quite overwhelming for a ‘new user’ and I was struggling with the same question. So for future reference: ItemDetail = Table(‘ItemDetail’, Column(‘id’, Integer, primary_key=True), Column(‘itemId’, Integer, ForeignKey(‘Item.id’)), Column(‘detailId’, Integer, ForeignKey(‘Detail.id’)), Column(‘endDate’, Date)) class Item(Base): __tablename__ = ‘Item’ id = Column(Integer, primary_key=True) … Read more
The paginator doesn’t support paginating associations, you’ll have to read the associated records manually in a separate query, and paginate that one, something along the lines of this: $product = $this->Products ->findBySlug($slug_prod) ->contain([‘Metas’, ‘Attachments’]) ->first(); $categoriesQuery = $this->Products->Categories ->find() ->innerJoinWith(‘Products’, function (\Cake\ORM\Query $query) use ($product) { return $query->where([ ‘Products.id’ => $product->id, ]); }) ->group(‘Categories.id’); $paginationOptions … Read more
Chriss I hope this simple example helps. Guess you have a Java class public class A { private B b; … } In UML you would model this relationship as an association from A to B: A -> B with the following modeling elements: Class B Class A + Property b : B [0..1] (owned … Read more
I’m a few months too late, but I was looking to solve this error and my situation was that I could not change the relationship to ‘face the other way’. The answer really is quite simple, you have to do this in your new action: @account.build_owner The reason why the form did not display using … Read more
Edit: Rails 3.1 supports nested associations. E.g: has_many :tasks has_many :assigments, :through => :tasks has_many :users, :through => :assignments There is no need for the solution given below. Refer to this screencast for more details. Original Answer You are passing a has_many :through association as a source for another has_many :through association. I don’t think … Read more
For now, CakePHP doesn’t take datasource configurations into account when creating joins, and I don’t think that this will be added in the near future, not least because cross database joins aren’t supported “out of the box” (as in, just prepend the database name and you’re set) in Postgres and SQLite. Assuming you are using … Read more
The build method signature is different for has_one and has_many associations. class User < ActiveRecord::Base has_one :profile has_many :messages end The build syntax for has_many association: user.messages.build The build syntax for has_one association: user.build_profile # this will work user.profile.build # this will throw error Read the has_one association documentation for more details.
Depending on your query needs you can put everything in the user document: {name:”Joe” ,roles:[“Admin”,”User”,”Engineer”] } To get all the Engineers, use: db.things.find( { roles : “Engineer” } ); If you want to maintain the roles in separate documents then you can include the document’s _id in the roles array instead of the name: {name:”Joe” … Read more
The main differenece is that bidirectional relationship provides navigational access in both directions, so that you can access the other side without explicit queries. Also it allows you to apply cascading options to both directions. Note that navigational access is not always good, especially for “one-to-very-many” and “many-to-very-many” relationships. Imagine a Group that contains thousands … Read more