I have these classes: @Entity public class Invoice implements Serializable { @Id @Basic(optional = false) private Integer number; private BigDecimal value; //Getters and setters } @Entity ...

I have a data model where a 'Top' object has between 0 and N 'Sub' objects. In SQL this is achieved with a foreign key dbo.Sub.TopId. var query = context.Top //.Include(t => t.Sub) Doesn't see...

I'm actually trying to use JPA @OneToOne annotation to link a Child entity to its Parent. It's working well, except the fact that when getting a list of Childs, the JPA engine (Hibernate in this c...

I'm rather inexperienced with databases and have just read about the "n+1 selects issue". My follow-up question: Assuming the database resides on the same machine as my program, is cached in RAM an...

EDIT I remade an entire project for this one problem. And thus, I remade the question. I want to be able to efficiently avoid N+1 and Cartesian joins joining together a 4 level deep entity with a ...

I visited http://guides.rubyonrails.org/active_record_querying.html after talking with a peer regarding N+1 and the serious performance implications of bad DB queries. ActiveRecord (Rails): clien...

Hibernate provides (at least) two options for getting around the N+1 query problem. The one is setting the FetchMode to Subselect, which generates a select with a IN-clause and a subselect within t...

I have a entity and fluent mapping that look like this. public class Client : EntityWithTypedId<long> { [Length(Max=50)] public virtual string GivenName { get; set; } public virtual ILi...

Foo has Title. Bar references Foo. I have a collection with Bars. I need a collection with Foo.Title. If i have 10 bars in collection, i'll call db 10 times. bars.Select(x=>x.Foo.Title) At t...