Hi All,

I'm not sure how to formulate a predicate expression for this:

Tables: Employee(EIdent) <---> EmployeeDeptartment(EDIdent) <--> Department(DIdent)

The EmployeeDepartment is basically a junction table with some additional info.

I want a collection of all Employees for a specific Department (using DIdent).

I'm using Adapter, .net 2.0.

Thanks,

Fishy

Fishy wrote:

I'm not sure how to formulate a predicate expression for this:

Tables: Employee(EIdent) <---> EmployeeDeptartment(EDIdent) <--> Department(DIdent)

The EmployeeDepartment is basically a junction table with some additional info.

I want a collection of all Employees for a specific Department (using DIdent).

I'm using Adapter, .net 2.0.

Hey Fishy,

From your description, it sounds like you just have to create a relationship (inner join hint) from Employee to EmployeeDepartment and then filter on EmployeeDepartment.DIdent.

What part are you struggling with?

Phil

I thought there would be someway to go directly to Employee thru some type of FetchCollection via the EmployeeDepartment.

Fishy wrote:

I thought there would be someway to go directly to Employee thru some type of FetchCollection via the EmployeeDepartment.

Assuming I understand you correctly, you could fetch the EmployeeDepartment filtered on DIdent, with a prefetch path to employee.

But then the collection you would have would be EmployeeDepartments, each with an employee attached to it. I don't think you can fetch a collection of Employees via the EmployeeDepartment entity, as the relationship from ed => e should be many to one.

HTH,

Phil

I did find this code in the manual.

' VB.NET, .NET 2.0
Dim customer As New CustomerEntity("CHOPS")
Dim adapter As New DataAccessAdapter()
Dim orders As EntityCollection(Of OrderEntity)= customer.Orders
adapter.FetchEntityCollection(orders, customer.GetRelationInfoOrders())

Which, I think, is what I want to do.

Thanks.

Fishy wrote:

I did find this code in the manual.

' VB.NET, .NET 2.0
Dim customer As New CustomerEntity("CHOPS")
Dim adapter As New DataAccessAdapter()
Dim orders As EntityCollection(Of OrderEntity)= customer.Orders
adapter.FetchEntityCollection(orders, customer.GetRelationInfoOrders())

Which, I think, is what I want to do.

Thanks.

I don't think this is possible in your case, since the related entities you want to fetch do not comprise a collection, but rather a single entity. Each EmployeeDepartmentEntity will have one and only one EmployeeEntity related to it, which (as far as I know) can't be fetched as a collection in the above manner.

If you reverse the above example, and think in terms of fetching a customer collection via the orders collection (which would not be possible), it would be a closer analogy to your own situation.

Could you post a snippet of code that you can't get working? It might make it easier to directly address the problem (plus it's possible I'm simply not understanding your questions).

Phil

I don't have a VB project that will allow me to syntax check this code, but something close to the following should work:

public function GetEDCollection(ByVal departmentId as int) as EntityCollection (of EmployeeEntity)

    Dim ED As New EntityCollection (of EmployeeEntity)

    Dim bucket as new RelationPredicateBucket()
    bucket.Relations.Add(EmployeeEntity.Relations.EmployeeDepartmentUsingEmployeeId)
    bucket.PredicateExpression.Add(EmployeeDepartmentFields.DepartmentId == departmentId)

    Dim adapter as new DataAccessAdapter()
    adapter.FetchEntityCollection(ED, bucket)

    return ED

end function

Thank you Phil.

Your code was perfect. Just exactly what I needed.

Thanks again,

Fishy