Complex Entity with fields from two or more tables.

Question

Hi,

Am evaluating Entity Framework 4.0 for certain requirements of my project. I have following queries on the same.

1) Is there anyway I can create a Custom Entity which can hold fields of two or more different tables? I tried doing this but seems to get compile errors.

2) Can the Custom Entity be directly created from the designer? I tried this but there seems to be a lot of mapping errors.

3) I want to construct a Custom Entity in which one of the property should contain a list of other child tables records. For example :

I have a employee table(Employee) and the address about the employee is stored is a child table(EmployeeAddress) . Each employee can have one or more records in the address table. It's a one to many relationship table(1...*) .

So I want to have a single entity holding a employee details along with his all address details in a property similary to the one given below.

Class Entity
{

private long EmpID;
Private string EmpName;
Private List<Address> Address=new List<Address>

}


Please advice/share if any of you guys came across the things I mentioned above.

Thanks,
Arvind

Answer 1

1. Yes. Lots of examples of this, e.g.:
http://msmvps.com/blogs/matthieu/archive/2008/06/20/entity-framework-how-to-use-entity-splitting-with-different-pk.aspx
http://www.robbagby.com/entity-framework/entity-framework-modeling-entity-splitting/

2. Yes. Please provide details of the issues you ran into and we can help.

3. This just sounds like a standard association, if you reverse engineer a database with an FK from EmployeeAddress to Employee, you will get just such a model.

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Answer 2

The product documentation also contains help for the scenarios you describe:

Walkthrough: Mapping an Entity to Multiple Tables
Entity Data Model Tools Tasks

Hope that helps.

-Brian

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This posting is provided "AS IS" with no warranties, and confers no rights.