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                 internal event DelegateConstraintNameChange BeforeConstraintNameChange;
  56
  57                 //if constraintName is not set then a name is
  58                 //created when it is added to
  59                 //the ConstraintCollection
  60                 //it can not be set to null, empty or duplicate
  61                 //once it has been added to the collection
  62                 private string _constraintName;
  63                 private PropertyCollection _properties;
  64
  65                 private Index _index;
  66
  67                 //Used for membership checking
  68                 private ConstraintCollection _constraintCollection;
  69
  70                 DataSet dataSet;
  71
  72                 protected Constraint ()
  73                 {
  74                         dataSet = null;
  75                         _properties = new PropertyCollection();
  76                 }
  77
  78                 [CLSCompliant (false)]
  79                 protected internal virtual DataSet _DataSet {
  80                         get { return dataSet; }
  81                 }
  82
  83                 [DataCategory ("Data")]
  84                 [DataSysDescription ("Indicates the name of this constraint.")]
  85                 [DefaultValue ("")]
  86                 public virtual string ConstraintName {
  87                         get{ return _constraintName == null ? "" : _constraintName; }
  88                         set{
  89                                 //This should only throw an exception when it
  90                                 //is a member of a ConstraintCollection which
  91                                 //means we should let the ConstraintCollection
  92                                 //handle exceptions when this value changes
  93                                 _onConstraintNameChange(value);
  94                                 _constraintName = value;
  95                         }
  96                 }
  97
  98                 [Browsable (false)]
  99                 [DataCategory ("Data")]
 100                 [DataSysDescription ("The collection that holds custom user information.")]
 101                 public PropertyCollection ExtendedProperties {
 102                         get { return _properties; }
 103                 }
 104
 105                 [DataSysDescription ("Indicates the table of this constraint.")]
 106                 public abstract DataTable Table {
 107                         get;
 108                 }
 109
 110                 internal ConstraintCollection ConstraintCollection {
 111                         get{ return _constraintCollection; }
 112                         set{ _constraintCollection = value; }
 113                 }
 114
 115                 private void _onConstraintNameChange (string newName)
 116                 {
 117                         if (null != BeforeConstraintNameChange)
 118                         {
 119                                 BeforeConstraintNameChange (this, newName);
 120                         }
 121                 }
 122
 123                 //call once before adding a constraint to a collection
 124                 //will throw an exception to prevent the add if a rule is broken
 125                 internal abstract void AddToConstraintCollectionSetup (ConstraintCollection collection);
 126
 127                 internal abstract bool IsConstraintViolated ();
 128
 129                 internal static void ThrowConstraintException(){
 130                         throw new ConstraintException("Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.");
 131                 }
 132
 133                 internal void AssertConstraint() {
 134                         if (IsConstraintViolated())
 135                                 ThrowConstraintException();
 136                 }
 137
 138                 internal abstract void AssertConstraint(DataRow row);
 139
 140                 internal virtual void RollbackAssert (DataRow row)
 141                 {
 142                 }
 143
 144                 //call once before removing a constraint to a collection
 145                 //can throw an exception to prevent the removal
 146                 internal abstract void RemoveFromConstraintCollectionCleanup (ConstraintCollection collection);
 147
 148                 [MonoTODO]
 149                 protected void CheckStateForProperty ()
 150                 {
 151                         throw new NotImplementedException ();
 152                 }
 153
 154                 protected internal void SetDataSet (DataSet dataSet)
 155                 {
 156                         this.dataSet = dataSet;
 157                 }
 158
 159                 internal Index Index
 160                 {
 161                         get {
 162                                 return _index;
 163                         }
 164                         set {
 165                                 if (_index != null) {
 166                                         _index.RemoveRef();
 167                                         Table.DropIndex(_index);
 168                                 }
 169
 170                                 _index = value;
 171
 172                                 if (_index != null) {
 173                                         _index.AddRef();
 174                                 }
 175                         }
 176                 }
 177
 178                 internal abstract bool IsColumnContained(DataColumn column);
 179                 internal abstract bool CanRemoveFromCollection(ConstraintCollection col, bool shouldThrow);
 180
 181                 /// <summary>
 182                 /// Gets the ConstraintName, if there is one, as a string.
 183                 /// </summary>
 184                 public override string ToString ()
 185                 {
 186                         return _constraintName == null ? "" : _constraintName;
 187                 }
 188
 189         }
 190 }