sdk/samples/all in on code/Visual Studio 2008/VBEFEntityDataModel/TablePerHierarchy/TPHClass.vb

   1 '****************************** Module Header ******************************'
   2 ' Module Name:    TPHClass.vb
   3 ' Project:        VBEFEntityDataModel
   4 ' Copyright (c) Microsoft Corporation.
   5 '
   6 ' This example demonstrates how to establish table per hierarchy inheritance.
   7 ' A table-per-type model is a way to model inheritance where each entity is
   8 ' mapped to a distinct table in the store. Then it shows how to query a list
   9 ' of people, get the corresponding properties of Person, Student and
  10 ' BusinessStudent.
  11 '
  12 ' This source is subject to the Microsoft Public License.
  13 ' See http://www.microsoft.com/opensource/licenses.mspx#Ms-PL.
  14 ' All other rights reserved.
  15 '
  16 ' THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND,
  17 ' EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
  18 ' WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
  19 '***************************************************************************'
  20
  21 #Region "Imports directives"
  22 Imports System
  23 Imports System.Collections.Generic
  24 Imports System.Linq
  25 Imports System.Text
  26 #End Region
  27
  28
  29 Namespace VBEFEntityDataModel.TablePerHierarchy
  30
  31     Friend Class TPHClass
  32
  33         ' Test the query method in TPHClass
  34         Public Shared Sub TPHTest()
  35             Query()
  36         End Sub
  37
  38         ' Query a list of people, print out the properties of Person,
  39         ' Student and BusinessStudent
  40         Public Shared Sub Query()
  41             Using context As New EFTPHEntities()
  42
  43                 Dim people = From p In context.PersonSet _
  44                     Select p
  45
  46                 For Each p In people
  47                     Console.WriteLine("Student {0} {1}", p.LastName, p.FirstName)
  48
  49                     If TypeOf p Is Student Then
  50                         Console.WriteLine("EnrollmentDate: {0}", _
  51                             DirectCast(p, Student).EnrollmentDate)
  52                     End If
  53
  54                     If TypeOf p Is BusinessStudent Then
  55                         Console.WriteLine("BusinessCredits: {0}", _
  56                             DirectCast(p, BusinessStudent).BusinessCredits)
  57                     End If
  58
  59                 Next
  60             End Using
  61         End Sub
  62     End Class
  63 End Namespace