mcs/class/referencesource/System.Data.Entity/System/Data/Metadata/Edm/ReferentialConstraint.cs

   1 //---------------------------------------------------------------------
   2 // <copyright file="ReferentialConstraint.cs" company="Microsoft">
   3 //      Copyright (c) Microsoft Corporation.  All rights reserved.
   4 // </copyright>
   5 //
   6 // @owner       Microsoft
   7 // @backupOwner Microsoft
   8 //---------------------------------------------------------------------
   9
  10 using System.Collections.Generic;
  11 using System.Collections.ObjectModel;
  12 using System.Data.Common;
  13
  14 namespace System.Data.Metadata.Edm
  15 {
  16     /// <summary>
  17     /// This class describes referential constraint on the relationships
  18     /// </summary>
  19     public sealed class ReferentialConstraint : MetadataItem
  20     {
  21         #region Constructors
  22         /// <summary>
  23         /// Constructs a new constraint on the relationship
  24         /// </summary>
  25         /// <param name="fromRole">role from which the relationship originates</param>
  26         /// <param name="toRole">role to which the relationship is linked/targeted to</param>
  27         /// <param name="toProperties">properties on entity type of from role which take part in the constraint</param>
  28         /// <param name="fromProperties">properties on entity type of to role which take part in the constraint</param>
  29         /// <exception cref="ArgumentNullException">Argument Null exception if any of the arguments is null</exception>
  30         internal ReferentialConstraint(RelationshipEndMember fromRole,
  31                                      RelationshipEndMember toRole,
  32                                      IEnumerable<EdmProperty> fromProperties,
  33                                      IEnumerable<EdmProperty> toProperties)
  34         {
  35             _fromRole = EntityUtil.GenericCheckArgumentNull(fromRole, "fromRole");
  36             _toRole = EntityUtil.GenericCheckArgumentNull(toRole, "toRole");
  37             _fromProperties = new ReadOnlyMetadataCollection<EdmProperty>(new MetadataCollection<EdmProperty>(
  38                 EntityUtil.GenericCheckArgumentNull(fromProperties, "fromProperties")));
  39             _toProperties = new ReadOnlyMetadataCollection<EdmProperty>(new MetadataCollection<EdmProperty>(
  40                 EntityUtil.GenericCheckArgumentNull(toProperties, "toProperties")));
  41         }
  42         #endregion
  43
  44         #region Fields
  45         private RelationshipEndMember _fromRole;
  46         private RelationshipEndMember _toRole;
  47         private readonly ReadOnlyMetadataCollection<EdmProperty> _fromProperties;
  48         private readonly ReadOnlyMetadataCollection<EdmProperty> _toProperties;
  49         #endregion
  50
  51         #region Properties
  52         /// <summary>
  53         /// Returns the kind of the type
  54         /// </summary>
  55         public override BuiltInTypeKind BuiltInTypeKind { get { return BuiltInTypeKind.ReferentialConstraint; } }
  56
  57         /// <summary>
  58         /// Returns the identity for this constraint
  59         /// </summary>
  60         internal override string Identity
  61         {
  62             get
  63             {
  64                 return this.FromRole.Name + "_" + this.ToRole.Name;
  65             }
  66         }
  67
  68         /// <summary>
  69         /// Returns the FromRole which takes part in this referential constraint
  70         /// </summary>
  71         /// <exception cref="System.ArgumentNullException">Thrown if value passed into setter is null</exception>
  72         /// <exception cref="System.InvalidOperationException">Thrown if the ReferentialConstraint instance is in ReadOnly state</exception>
  73         [MetadataProperty(BuiltInTypeKind.RelationshipEndMember, false)]
  74         public RelationshipEndMember FromRole
  75         {
  76             get
  77             {
  78                 return _fromRole;
  79             }
  80         }
  81
  82         /// <summary>
  83         /// Returns the ToRole which takes part in this referential constraint
  84         /// </summary>
  85         /// <exception cref="System.ArgumentNullException">Thrown if value passed into setter is null</exception>
  86         /// <exception cref="System.InvalidOperationException">Thrown if the ReferentialConstraint instance is in ReadOnly state</exception>
  87         [MetadataProperty(BuiltInTypeKind.RelationshipEndMember, false)]
  88         public RelationshipEndMember ToRole
  89         {
  90             get
  91             {
  92                 return _toRole;
  93             }
  94         }
  95
  96         /// <summary>
  97         /// Returns the collection of properties on the from role on which the constraint is defined on
  98         /// </summary>
  99         [MetadataProperty(BuiltInTypeKind.EdmProperty, true)]
 100         public ReadOnlyMetadataCollection<EdmProperty> FromProperties
 101         {
 102             get
 103             {
 104                 return _fromProperties;
 105             }
 106         }
 107
 108         /// <summary>
 109         /// Returns the collection of properties on the ToRole on whose value the constraint is defined on
 110         /// </summary>
 111         [MetadataProperty(BuiltInTypeKind.EdmProperty, true)]
 112         public ReadOnlyMetadataCollection<EdmProperty> ToProperties
 113         {
 114             get
 115             {
 116                 return _toProperties;
 117             }
 118         }
 119         #endregion
 120
 121         #region Methods
 122         /// <summary>
 123         /// Overriding System.Object.ToString to provide better String representation
 124         /// for this type.
 125         /// </summary>
 126         public override string ToString()
 127         {
 128             return this.FromRole.Name + "_" + this.ToRole.Name;
 129         }
 130
 131         /// <summary>
 132         /// Sets this item to be read-only, once this is set, the item will never be writable again.
 133         /// </summary>
 134         internal override void SetReadOnly()
 135         {
 136             if (!IsReadOnly)
 137             {
 138                 base.SetReadOnly();
 139
 140                 RelationshipEndMember fromRole = FromRole;
 141                 if (fromRole != null)
 142                 {
 143                     fromRole.SetReadOnly();
 144                 }
 145
 146                 RelationshipEndMember toRole = ToRole;
 147                 if (toRole != null)
 148                 {
 149                     toRole.SetReadOnly();
 150                 }
 151                 this.FromProperties.Source.SetReadOnly();
 152                 this.ToProperties.Source.SetReadOnly();
 153             }
 154         }
 155         #endregion
 156     }
 157 }