EntityContainer Classe

Definição

public ref class EntityContainer sealed : System::Data::Metadata::Edm::GlobalItem

public sealed class EntityContainer : System.Data.Metadata.Edm.GlobalItem

type EntityContainer = class
    inherit GlobalItem

Public NotInheritable Class EntityContainer
Inherits GlobalItem

Herança

Object

MetadataItem

GlobalItem

EntityContainer

Exemplos

O exemplo de código a seguir demonstra como obter um workspace de metadados da conexão e, em seguida, usar esse workspace de metadados para recuperar informações sobre os contêineres de entidade no modelo de dados especificado. Observe que o workspace de metadados é um componente de serviço de runtime que fornece suporte para recuperar metadados.

O exemplo de código usa um CSpace e um SSpace para especificar o modelo. Representa CSpace o nome padrão do modelo conceitual. Representa SSpace o nome padrão do modelo de armazenamento.

O GetEntityContainers método obtém uma coleção de contêineres de entidade e, em seguida, itera por meio da coleção para obter cada conjunto de entidades e conjunto de associação no contêiner especificado. O exemplo de código usa o Modelo AdventureWorks.

using System;  
using System.Data;  
using System.Data.EntityClient;  
using System.Data.Metadata.Edm;  
using System.Collections.ObjectModel;  

class GetEntityContainerExample  
{  
  static void Main()  
  {  
    try  
    {  
       // Establish a connection to the underlying data provider by   
       // using the connection string specified in the config file.  
       using (EntityConnection connection =  
          new EntityConnection("Name=AdventureWorksEntities"))  
       {  
         // Open the connection.  
         connection.Open();  

         // Access the metadata workspace.  
         MetadataWorkspace workspace =   
            connection.GetMetadataWorkspace();  

         // Get the entity containers in the conceptual model.  
         GetEntityContainers(workspace, DataSpace.CSpace);  

         // Get the entity containers in the storage model.  
             GetEntityContainers(workspace, DataSpace.SSpace);  
       }  
    }  
    catch (MetadataException exceptionMetadata)  
    {  
      Console.WriteLine("MetadataException: {0}",   
                       exceptionMetadata.Message);  
    }  
    catch (System.Data.MappingException exceptionMapping)  
    {  
      Console.WriteLine("MappingException: {0}",  
                       exceptionMapping.Message);  
    }  
  }  

  public static void GetEntityContainers(  
      MetadataWorkspace workspace, DataSpace model)  
  {  
    // Get a collection of the entity containers.  
    ReadOnlyCollection<EntityContainer> containers =   
         workspace.GetItems<EntityContainer>(model);  

    // Iterate through the collection to get each entity container.  
    foreach (EntityContainer container in containers)  
    {  
       Console.WriteLine("EntityContainer Name: {0} ",   
                        container.Name);  

       // EntitySetBase is a super type for   
       // EntitySets and RelationshipSets.   
       // Iterate through the collection to get each EntitySetBase.  
       foreach (EntitySetBase baseSet in container.BaseEntitySets)  
       {  
          // Check if this instance is an EntitySet.  
          if (baseSet is EntitySet)  
          {  
             Console.WriteLine(  
                "  EntitySet Name: {0} , EntityType Name: {1} ",  
                baseSet.Name, baseSet.ElementType.FullName);  
          }  

         // RelationshipSet is a super type for AssociationSet.  
         // Check if this instance is an AssociationSet.  
         if (baseSet is AssociationSet)  
         {  
            Console.WriteLine(  
               "  AssociationSet Name: {0} , " +  
               "AssociationType Name: {1} ",  
                baseSet.Name, baseSet.ElementType.FullName);  

            // Get the AssociationSet.  
            AssociationSet associationSet =   
                  baseSet as AssociationSet;  

            // Iterate through the collection to get   
            // each AssociatedSetEnd.  
            foreach (AssociationSetEnd end in   
               associationSet.AssociationSetEnds)  
            {  
               Console.WriteLine(  
                  "   EntitySet Name: {0} , Name: {1} ",  
                  end.EntitySet, end.Name);  
            }  
         }  
      }  
    }  
  }  
}  

Imports System  
Imports System.Collections.ObjectModel  
Imports System.Data  
Imports System.Data.EntityClient  
Imports System.Data.Metadata.Edm  

Class GetEntityContainerExample  
  Public Shared Sub Main()  
    Try  
      ' Establish a connection to the underlying data provider by   
      ' using the connection string specified in the config file.  
      Using connection As EntityConnection = _  
        New EntityConnection("Name=AdventureWorksEntities")  

        ' Open the connection.  
        connection.Open()  

        ' Access the metadata workspace.  
        Dim workspace As MetadataWorkspace = _  
           connection.GetMetadataWorkspace  

        ' Get the entity containers in the conceptual model.  
        GetEntityContainers(workspace, DataSpace.CSpace)  

        ' Get the entity containers in the storage model.  
        GetEntityContainers(workspace, DataSpace.SSpace)  
      End Using  
    Catch exceptionMetadata As MetadataException  
       Console.WriteLine("MetadataException: {0}", _  
          exceptionMetadata.Message)  
    Catch exceptionMapping As MappingException  
       Console.WriteLine("MappingException: {0}", _  
          exceptionMapping.Message)  
     End Try  
  End Sub  

  Public Shared Sub GetEntityContainers( _  
    ByVal workspace As MetadataWorkspace, ByVal model As DataSpace)  

    ' Get a collection of the entity containers.  
    Dim containers As ReadOnlyCollection(Of EntityContainer) = _  
       workspace.GetItems(Of EntityContainer)(model)  

    ' Iterate through the collection to get each entity container.  
    Dim container As EntityContainer  
    For Each container In containers  
      Console.WriteLine("EntityContainer Name: {0} ", container.Name)  

      ' EntitySetBase is a super type for   
      ' EntitySets and RelationshipSets.   
      ' Iterate through the collection to get each EntitySetBase.  
      Dim baseSet As EntitySetBase  
      For Each baseSet In container.BaseEntitySets  
         ' Check if this instance is an EntitySet.  
         If TypeOf baseSet Is EntitySet Then  
           Console.WriteLine( _  
              "  EntitySet Name: {0} , EntityType Name: {1} ", _  
              baseSet.Name, baseSet.ElementType.FullName)  
          End If  

          ' RelationshipSet is a super type for AssociationSet.  
          ' Check if this instance is an AssociationSet.  
          If TypeOf baseSet Is AssociationSet Then  
            Console.WriteLine( _  
              "  AssociationSet Name: {0} , " + _  
              "AssociationType Name: {1} ", _  
              baseSet.Name, baseSet.ElementType.FullName)  

            ' Get the AssociationSet.  
            Dim associationSet As AssociationSet = _  
               TryCast(baseSet, AssociationSet)  

            ' Iterate through the collection to get   
            '  each AssociatedSetEnd.  
            Dim endMember As AssociationSetEnd  
            For Each endMember In associationSet.AssociationSetEnds  
              Console.WriteLine( _  
                 "   EntitySet Name: {0} , Name: {1} ", _  
                 endMember.EntitySet, endMember.Name)  
            Next  
          End If  
      Next  
    Next  
  End Sub  
End Class  

Comentários

No nível conceitual, a EntityContainer classe representa um contêiner que será mapeado para um objeto de banco de dados no esquema de metadados de armazenamento. No nível de armazenamento, a EntityContainer classe representa uma descrição da tabela e/ou relações de chave que persistem dados para aplicativos criados no modelo. Para obter mais informações sobre os contêineres de entidade em um modelo conceitual, consulte o contêiner Entity.