CODEWITHSUNDEEP
c#entity-frameworkentity-framework-4
outlookrperson
outlookrperson

Reputation: 2821

Querying a derived entity in the ObjectContext (Table-per-hierarchy)

I´m doing the Walkthrough: Mapping Inheritance - Table-per-Hierarchy (Entity Data Model Tools).

This is the model:

Entities Data Model

The entities Instructor and Student are derived types with the BaseType Person.

The problem is: How can I query the Instructor and Student entities directly in LINQ if they are not visible in ObjectContext?

I was expecting to do somenthig like this:

var result = from student in ctx.Students select student;

The derived entities seems to exist only as entities (EntityObject) and not as ObjectSet.

Thanks!

Upvotes: 2

Views: 626

Answers (1)

casperOne
casperOne

Reputation: 74540

You should have a People property on the ObjectContext class that is generated for you. From there, you can get all the base types:

var allPeople = ctx.People;

Or, if you want a specific derived type, you can use the OfType extension method on IQueryable<T>, like so:

var students = allPeople.OfType<Student>();
var instructors = allPeople.OfType<Instructor>();

Upvotes: 1

Related Questions