mcs/class/System.Data/System.Data/Constraint.cs

   1 //
   2 // System.Data.Constraint.cs
   3 //
   4 // Author:
   5 //      Franklin Wise <gracenote@earthlink.net>
   6 //      Daniel Morgan
   7 //      Tim Coleman (tim@timcoleman.com)
   8 //
   9 //
  10 // (C) Ximian, Inc. 2002
  11 // Copyright (C) Tim Coleman, 2002
  12 //
  13
  14 //
  15 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  16 //
  17 // Permission is hereby granted, free of charge, to any person obtaining
  18 // a copy of this software and associated documentation files (the
  19 // "Software"), to deal in the Software without restriction, including
  20 // without limitation the rights to use, copy, modify, merge, publish,
  21 // distribute, sublicense, and/or sell copies of the Software, and to
  22 // permit persons to whom the Software is furnished to do so, subject to
  23 // the following conditions:
  24 //
  25 // The above copyright notice and this permission notice shall be
  26 // included in all copies or substantial portions of the Software.
  27 //
  28 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  29 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  30 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  31 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  32 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  33 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  34 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  35 //
  36
  37 using System;
  38 using System.Collections;
  39 using System.ComponentModel;
  40 using System.Runtime.InteropServices;
  41 using System.Runtime.Serialization;
  42 using System.Data.Common;
  43
  44 namespace System.Data {
  45         [Serializable]
  46         internal delegate void DelegateConstraintNameChange (object sender, string newName);
  47
  48         [DefaultProperty ("ConstraintName")]
  49 #if !NET_2_0
  50         [Serializable]
  51 #endif
  52         [TypeConverterAttribute (typeof (ConstraintConverter))]
  53         public abstract class Constraint
  54         {
  55                 static readonly object beforeConstraintNameChange = new object ();
  56
  57                 EventHandlerList events = new EventHandlerList ();
  58
  59                 internal event DelegateConstraintNameChange BeforeConstraintNameChange {
  60                         add { events.AddHandler (beforeConstraintNameChange, value); }
  61                         remove { events.RemoveHandler (beforeConstraintNameChange, value); }
  62                 }
  63
  64                 //if constraintName is not set then a name is
  65                 //created when it is added to
  66                 //the ConstraintCollection
  67                 //it can not be set to null, empty or duplicate
  68                 //once it has been added to the collection
  69                 private string _constraintName;
  70                 private PropertyCollection _properties;
  71
  72                 private Index _index;
  73
  74                 //Used for membership checking
  75                 private ConstraintCollection _constraintCollection;
  76
  77                 DataSet dataSet;
  78
  79                 protected Constraint ()
  80                 {
  81                         dataSet = null;
  82                         _properties = new PropertyCollection();
  83                 }
  84
  85                 [CLSCompliant (false)]
  86                 protected internal virtual DataSet _DataSet {
  87                         get { return dataSet; }
  88                 }
  89
  90                 [DataCategory ("Data")]
  91 #if !NET_2_0
  92                 [DataSysDescription ("Indicates the name of this constraint.")]
  93 #endif
  94                 [DefaultValue ("")]
  95                 public virtual string ConstraintName {
  96                         get{ return _constraintName == null ? "" : _constraintName; }
  97                         set{
  98                                 //This should only throw an exception when it
  99                                 //is a member of a ConstraintCollection which
 100                                 //means we should let the ConstraintCollection
 101                                 //handle exceptions when this value changes
 102                                 _onConstraintNameChange(value);
 103                                 _constraintName = value;
 104                         }
 105                 }
 106
 107                 [Browsable (false)]
 108                 [DataCategory ("Data")]
 109 #if !NET_2_0
 110                 [DataSysDescription ("The collection that holds custom user information.")]
 111 #endif
 112                 public PropertyCollection ExtendedProperties {
 113                         get { return _properties; }
 114 #if NET_2_0
 115                         internal set { _properties = value; }
 116 #endif
 117                 }
 118
 119 #if !NET_2_0
 120                 [DataSysDescription ("Indicates the table of this constraint.")]
 121 #endif
 122                 public abstract DataTable Table {
 123                         get;
 124                 }
 125
 126                 internal ConstraintCollection ConstraintCollection {
 127                         get{ return _constraintCollection; }
 128                         set{ _constraintCollection = value; }
 129                 }
 130
 131                 private void _onConstraintNameChange (string newName)
 132                 {
 133                         DelegateConstraintNameChange eh = events [beforeConstraintNameChange] as DelegateConstraintNameChange;
 134                         if (eh != null)
 135                                 eh (this, newName);
 136                 }
 137
 138                 //call once before adding a constraint to a collection
 139                 //will throw an exception to prevent the add if a rule is broken
 140                 internal abstract void AddToConstraintCollectionSetup (ConstraintCollection collection);
 141
 142                 internal abstract bool IsConstraintViolated ();
 143
 144                 internal static void ThrowConstraintException(){
 145                         throw new ConstraintException("Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.");
 146                 }
 147
 148                 bool initInProgress = false;
 149                 internal virtual bool InitInProgress {
 150                         get { return initInProgress; }
 151                         set { initInProgress = value; }
 152                 }
 153
 154                 internal virtual void FinishInit (DataTable table)
 155                 {
 156                 }
 157
 158                 internal void AssertConstraint()
 159                 {
 160                         // The order is important.. IsConstraintViolated fills the RowErrors if it detects
 161                         // a violation
 162                         if (!IsConstraintViolated())
 163                                 return;
 164                         if (Table._duringDataLoad || (Table.DataSet != null && !Table.DataSet.EnforceConstraints))
 165                                 return;
 166                         ThrowConstraintException();
 167                 }
 168
 169                 internal abstract void AssertConstraint(DataRow row);
 170
 171                 internal virtual void RollbackAssert (DataRow row)
 172                 {
 173                 }
 174
 175                 //call once before removing a constraint to a collection
 176                 //can throw an exception to prevent the removal
 177                 internal abstract void RemoveFromConstraintCollectionCleanup (ConstraintCollection collection);
 178
 179                 [MonoTODO]
 180                 protected void CheckStateForProperty ()
 181                 {
 182                         throw new NotImplementedException ();
 183                 }
 184
 185                 protected internal void SetDataSet (DataSet dataSet)
 186                 {
 187                         this.dataSet = dataSet;
 188                 }
 189
 190                 internal Index Index
 191                 {
 192                         get {
 193                                 return _index;
 194                         }
 195                         set {
 196                                 if (_index != null) {
 197                                         _index.RemoveRef();
 198                                         Table.DropIndex(_index);
 199                                 }
 200
 201                                 _index = value;
 202
 203                                 if (_index != null) {
 204                                         _index.AddRef();
 205                                 }
 206                         }
 207                 }
 208
 209                 internal abstract bool IsColumnContained(DataColumn column);
 210                 internal abstract bool CanRemoveFromCollection(ConstraintCollection col, bool shouldThrow);
 211
 212                 /// <summary>
 213                 /// Gets the ConstraintName, if there is one, as a string.
 214                 /// </summary>
 215                 public override string ToString ()
 216                 {
 217                         return _constraintName == null ? "" : _constraintName;
 218                 }
 219
 220         }
 221 }