mcs/class/referencesource/System.Data.Entity/System/Data/EntityModel/SchemaObjectModel/Relationship.cs

   1 //---------------------------------------------------------------------
   2 // <copyright file="Relationship.cs" company="Microsoft">
   3 //      Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 //
   6 // @owner       Microsoft
   7 // @backupOwner Microsoft
   8 //---------------------------------------------------------------------
   9
  10 namespace System.Data.EntityModel.SchemaObjectModel
  11 {
  12     using System.Collections.Generic;
  13     using System.Data.Metadata.Edm;
  14     using System.Data.Objects.DataClasses;
  15     using System.Diagnostics;
  16     using System.Xml;
  17
  18     /// <summary>
  19     /// Represents an Association element
  20     /// </summary>
  21     internal sealed class Relationship : SchemaType, IRelationship
  22     {
  23         private RelationshipKind _relationshipKind;
  24         private RelationshipEndCollection _ends;
  25         private List<ReferentialConstraint> _constraints;
  26         private bool _isForeignKey;
  27
  28         /// <summary>
  29         /// Construct a Relationship object
  30         /// </summary>
  31         /// <param name="parent">the parent</param>
  32         /// <param name="kind">the kind of relationship</param>
  33         public Relationship(Schema parent, RelationshipKind kind)
  34         : base(parent)
  35         {
  36             RelationshipKind = kind;
  37
  38             if (Schema.DataModel == SchemaDataModelOption.EntityDataModel)
  39             {
  40                 _isForeignKey = false;
  41                 OtherContent.Add(Schema.SchemaSource);
  42             }
  43             else if (Schema.DataModel == SchemaDataModelOption.ProviderDataModel)
  44             {
  45                 _isForeignKey = true;
  46             }
  47         }
  48
  49
  50         /// <summary>
  51         /// List of Ends defined for this Association
  52         /// </summary>
  53         public IList<IRelationshipEnd> Ends
  54         {
  55             get
  56             {
  57                 if ( _ends == null )
  58                     _ends = new RelationshipEndCollection();
  59                 return _ends;
  60             }
  61         }
  62
  63         /// <summary>
  64         /// Returns the list of constraints on this relation
  65         /// </summary>
  66         public IList<ReferentialConstraint> Constraints
  67         {
  68             get
  69             {
  70                 if (_constraints == null)
  71                 {
  72                     _constraints = new List<ReferentialConstraint>();
  73                 }
  74                 return _constraints;
  75             }
  76         }
  77
  78         public bool TryGetEnd( string roleName, out IRelationshipEnd end )
  79         {
  80             return _ends.TryGetEnd( roleName, out end );
  81         }
  82
  83
  84         /// <summary>
  85         /// Is this an Association
  86         /// </summary>
  87         public RelationshipKind RelationshipKind
  88         {
  89             get
  90             {
  91                 return _relationshipKind;
  92             }
  93             private set
  94             {
  95                 _relationshipKind = value;
  96             }
  97         }
  98
  99         /// <summary>
 100         /// Is this a foreign key (aka foreign key) relationship?
 101         /// </summary>
 102         public bool IsForeignKey
 103         {
 104             get { return _isForeignKey; }
 105         }
 106
 107         /// <summary>
 108         /// do whole element validation
 109         /// </summary>
 110         /// <returns></returns>
 111         internal override void Validate()
 112         {
 113             base.Validate();
 114
 115             bool foundOperations = false;
 116             foreach ( RelationshipEnd end in Ends )
 117             {
 118                 end.Validate();
 119                 if ( RelationshipKind == RelationshipKind.Association )
 120                 {
 121                     if ( end.Operations.Count > 0 )
 122                     {
 123                         if ( foundOperations )
 124                             end.AddError( ErrorCode.InvalidOperation, EdmSchemaErrorSeverity.Error, System.Data.Entity.Strings.InvalidOperationMultipleEndsInAssociation);
 125                         foundOperations = true;
 126                     }
 127                 }
 128             }
 129
 130             if (Constraints.Count == 0)
 131             {
 132                 if (this.Schema.DataModel == SchemaDataModelOption.ProviderDataModel)
 133                 {
 134                     AddError(ErrorCode.MissingConstraintOnRelationshipType,
 135                              EdmSchemaErrorSeverity.Error,
 136                              System.Data.Entity.Strings.MissingConstraintOnRelationshipType(FQName));
 137                 }
 138             }
 139             else
 140             {
 141                 foreach (ReferentialConstraint constraint in Constraints)
 142                 {
 143                     constraint.Validate();
 144                 }
 145             }
 146         }
 147
 148         /// <summary>
 149         /// do whole element resolution
 150         /// </summary>
 151         internal override void ResolveTopLevelNames()
 152         {
 153             base.ResolveTopLevelNames();
 154
 155             foreach ( RelationshipEnd end in Ends )
 156                 end.ResolveTopLevelNames();
 157
 158             foreach (ReferentialConstraint referentialConstraint in Constraints)
 159             {
 160                 referentialConstraint.ResolveTopLevelNames();
 161             }
 162         }
 163
 164         protected override bool HandleElement(XmlReader reader)
 165         {
 166             if (base.HandleElement(reader))
 167             {
 168                 return true;
 169             }
 170             else if (CanHandleElement(reader, XmlConstants.End))
 171             {
 172                 HandleEndElement(reader);
 173                 return true;
 174             }
 175             else if (CanHandleElement(reader, XmlConstants.ReferentialConstraint))
 176             {
 177                 HandleConstraintElement(reader);
 178                 return true;
 179             }
 180             return false;
 181         }
 182
 183         /// <summary>
 184         /// handle the End child element
 185         /// </summary>
 186         /// <param name="reader">XmlReader positioned at the end element</param>
 187         private void HandleEndElement(XmlReader reader)
 188         {
 189             Debug.Assert(reader != null);
 190             RelationshipEnd end = new RelationshipEnd(this);
 191             end.Parse(reader);
 192
 193             if (Ends.Count == 2)
 194             {
 195                 AddError( ErrorCode.InvalidAssociation, EdmSchemaErrorSeverity.Error, System.Data.Entity.Strings.TooManyAssociationEnds(FQName ) );
 196                 return;
 197             }
 198
 199             Ends.Add(end);
 200         }
 201
 202         /// <summary>
 203         /// handle the constraint element
 204         /// </summary>
 205         /// <param name="reader">XmlReader positioned at the constraint element</param>
 206         private void HandleConstraintElement(XmlReader reader)
 207         {
 208             Debug.Assert(reader != null);
 209
 210             ReferentialConstraint constraint = new ReferentialConstraint(this);
 211             constraint.Parse(reader);
 212             this.Constraints.Add(constraint);
 213
 214             if (this.Schema.DataModel == SchemaDataModelOption.EntityDataModel && this.Schema.SchemaVersion >= XmlConstants.EdmVersionForV2)
 215             {
 216                 // in V2, referential constraint implies foreign key
 217                 _isForeignKey = true;
 218             }
 219         }
 220
 221     }
 222 }