mcs/class/System.Data/System.Data/ForeignKeyConstraint.cs

   1 //
   2 // System.Data.ForeignKeyConstraint.cs
   3 //
   4 // Author:
   5 //   Franklin Wise <gracenote@earthlink.net>
   6 //   Daniel Morgan <danmorg@sc.rr.com>
   7 //
   8 // (C) 2002 Franklin Wise
   9 // (C) 2002 Daniel Morgan
  10 //
  11
  12 //
  13 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  14 //
  15 // Permission is hereby granted, free of charge, to any person obtaining
  16 // a copy of this software and associated documentation files (the
  17 // "Software"), to deal in the Software without restriction, including
  18 // without limitation the rights to use, copy, modify, merge, publish,
  19 // distribute, sublicense, and/or sell copies of the Software, and to
  20 // permit persons to whom the Software is furnished to do so, subject to
  21 // the following conditions:
  22 //
  23 // The above copyright notice and this permission notice shall be
  24 // included in all copies or substantial portions of the Software.
  25 //
  26 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  27 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  28 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  29 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  30 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  31 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  32 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  33 //
  34
  35 using System;
  36 using System.Collections;
  37 using System.ComponentModel;
  38 using System.Runtime.InteropServices;
  39 using System.Data.Common;
  40
  41 namespace System.Data {
  42         [Editor ("Microsoft.VSDesigner.Data.Design.ForeignKeyConstraintEditor, " + Consts.AssemblyMicrosoft_VSDesigner,
  43                  "System.Drawing.Design.UITypeEditor, " + Consts.AssemblySystem_Drawing)]
  44         [DefaultProperty ("ConstraintName")]
  45         public class ForeignKeyConstraint : Constraint
  46         {
  47                 private UniqueConstraint _parentUniqueConstraint;
  48                 //FIXME: create a class which will wrap this collection
  49                 private DataColumn [] _parentColumns;
  50                 //FIXME: create a class which will wrap this collection
  51                 private DataColumn [] _childColumns;
  52                 private Rule _deleteRule = Rule.Cascade;
  53                 private Rule _updateRule = Rule.Cascade;
  54                 private AcceptRejectRule _acceptRejectRule = AcceptRejectRule.None;
  55                 private string _parentTableName;
  56                 private string _parentTableNamespace;
  57                 private string _childTableName;
  58
  59                 //FIXME: remove those; and use only DataColumns[]
  60                 private string [] _parentColumnNames;
  61                 private string [] _childColumnNames;
  62
  63                 #region Constructors
  64
  65                 public ForeignKeyConstraint(DataColumn parentColumn, DataColumn childColumn)
  66                 {
  67                         if (null == parentColumn || null == childColumn) {
  68                                 throw new NullReferenceException("Neither parentColumn or" +
  69                                         " childColumn can be null.");
  70                         }
  71                         _foreignKeyConstraint(null, new DataColumn[] {parentColumn},
  72                                         new DataColumn[] {childColumn});
  73                 }
  74
  75                 public ForeignKeyConstraint(DataColumn[] parentColumns, DataColumn[] childColumns)
  76                 {
  77                         _foreignKeyConstraint(null, parentColumns, childColumns);
  78                 }
  79
  80                 public ForeignKeyConstraint(string constraintName, DataColumn parentColumn, DataColumn childColumn)
  81                 {
  82                         if (null == parentColumn || null == childColumn) {
  83                                 throw new NullReferenceException("Neither parentColumn or" +
  84                                         " childColumn can be null.");
  85                         }
  86
  87                         _foreignKeyConstraint(constraintName, new DataColumn[] {parentColumn},
  88                                         new DataColumn[] {childColumn});
  89                 }
  90
  91                 public ForeignKeyConstraint(string constraintName, DataColumn[] parentColumns, DataColumn[] childColumns)
  92                 {
  93                         _foreignKeyConstraint(constraintName, parentColumns, childColumns);
  94                 }
  95
  96                 //special case
  97                 [Browsable (false)]
  98                 public ForeignKeyConstraint(string constraintName, string parentTableName, string[] parentColumnNames, string[] childColumnNames, AcceptRejectRule acceptRejectRule, Rule deleteRule, Rule updateRule)
  99                 {
 100                         int i;
 101                         InitInProgress = true;
 102                         base.ConstraintName = constraintName;
 103
 104                         // "parentTableName" is searched in the "DataSet" to which the "DataTable"
 105                         // from which AddRange() is called
 106                         // childTable is the "DataTable" which calls AddRange()
 107
 108                         // Keep reference to parentTableName to resolve later
 109                         _parentTableName = parentTableName;
 110
 111                         // Keep a copy of parentColumnNames to resolve later
 112                         _parentColumnNames = new string [parentColumnNames.Length];
 113                         for (i = 0; i < parentColumnNames.Length; i++)
 114                                _parentColumnNames[i] = parentColumnNames[i];
 115
 116                         // Keep a copy of childColumnNames to resolve later
 117                         _childColumnNames = new string [childColumnNames.Length];
 118                         for (i = 0; i < childColumnNames.Length; i++)
 119                                _childColumnNames[i] = childColumnNames[i];
 120
 121
 122                         _acceptRejectRule = acceptRejectRule;
 123                         _deleteRule = deleteRule;
 124                         _updateRule = updateRule;
 125                 }
 126
 127                 internal override void FinishInit (DataTable childTable)
 128                 {
 129                         if (childTable.DataSet == null)
 130                                 throw new InvalidConstraintException ("ChildTable : " + childTable.TableName + " does not belong to any DataSet");
 131
 132                         DataSet dataSet = childTable.DataSet;
 133                         _childTableName = childTable.TableName;
 134
 135                         if (!dataSet.Tables.Contains (_parentTableName))
 136                                 throw new InvalidConstraintException ("Table : " + _parentTableName + "does not exist in DataSet : " + dataSet);
 137
 138                         DataTable parentTable = dataSet.Tables [_parentTableName];
 139
 140                         int i = 0, j = 0;
 141
 142                         if (_parentColumnNames.Length < 0 || _childColumnNames.Length < 0)
 143                                 throw new InvalidConstraintException ("Neither parent nor child columns can be zero length");
 144
 145                         if (_parentColumnNames.Length != _childColumnNames.Length)
 146                                 throw new InvalidConstraintException ("Both parent and child columns must be of same length");
 147                         DataColumn[] parentColumns = new DataColumn [_parentColumnNames.Length];
 148                         DataColumn[] childColumns = new DataColumn [_childColumnNames.Length];
 149
 150                         foreach (string parentCol in _parentColumnNames){
 151                                 if (!parentTable.Columns.Contains (parentCol))
 152                                         throw new InvalidConstraintException ("Table : " + _parentTableName + "does not contain the column :" + parentCol);
 153                                 parentColumns [i++] = parentTable. Columns [parentCol];
 154                         }
 155
 156                         foreach (string childCol in _childColumnNames){
 157                                 if (!childTable.Columns.Contains (childCol))
 158                                         throw new InvalidConstraintException ("Table : " + _childTableName + "does not contain the column : " + childCol);
 159                                 childColumns [j++] = childTable.Columns [childCol];
 160                         }
 161                         _validateColumns (parentColumns, childColumns);
 162                         _parentColumns = parentColumns;
 163                         _childColumns = childColumns;
 164                         parentTable.Namespace = _parentTableNamespace;
 165                         InitInProgress = false;
 166                 }
 167
 168                 [Browsable (false)]
 169                 public ForeignKeyConstraint (string constraintName, string parentTableName, string parentTableNamespace, string[] parentColumnNames, string[] childColumnNames, AcceptRejectRule acceptRejectRule, Rule deleteRule, Rule updateRule)
 170                 {
 171                         InitInProgress = true;
 172                         base.ConstraintName = constraintName;
 173
 174                         // "parentTableName" is searched in the "DataSet" to which the "DataTable"
 175                         // from which AddRange() is called
 176                         // childTable is the "DataTable" which calls AddRange()
 177
 178                         // Keep reference to parentTableName to resolve later
 179                         _parentTableName = parentTableName;
 180                         _parentTableNamespace = parentTableNamespace;
 181
 182                         // Keep reference to parentColumnNames to resolve later
 183                         _parentColumnNames = parentColumnNames;
 184
 185                         // Keep reference to childColumnNames to resolve later
 186                         _childColumnNames = childColumnNames;
 187
 188                         _acceptRejectRule = acceptRejectRule;
 189                         _deleteRule = deleteRule;
 190                         _updateRule = updateRule;
 191                 }
 192
 193                 private void _foreignKeyConstraint(string constraintName, DataColumn[] parentColumns,
 194                                 DataColumn[] childColumns)
 195                 {
 196                         int i;
 197                         //Validate
 198                         _validateColumns(parentColumns, childColumns);
 199
 200                         //Set Constraint Name
 201                         base.ConstraintName = constraintName;
 202
 203                         //copy the columns - Do not keep reference #672113
 204                         _parentColumns = new DataColumn [parentColumns.Length];
 205                         for (i = 0; i < parentColumns.Length; i++)
 206                                _parentColumns[i] = parentColumns[i];
 207
 208                         _childColumns = new DataColumn [childColumns.Length];
 209                         for (i = 0; i < childColumns.Length; i++)
 210                                _childColumns[i] = childColumns[i];
 211                 }
 212
 213 #endregion // Constructors
 214
 215 #region Helpers
 216
 217                 private void _validateColumns(DataColumn[] parentColumns, DataColumn[] childColumns)
 218                 {
 219                         //not null
 220                         if (null == parentColumns || null == childColumns)
 221                                 throw new ArgumentNullException();
 222
 223                         //at least one element in each array
 224                         if (parentColumns.Length < 1 || childColumns.Length < 1)
 225                                 throw new ArgumentException("Neither ParentColumns or ChildColumns can't be" +
 226                                                 " zero length.");
 227
 228                         //same size arrays
 229                         if (parentColumns.Length != childColumns.Length)
 230                                 throw new ArgumentException("Parent columns and child columns must be the same length.");
 231
 232
 233                         DataTable ptable = parentColumns[0].Table;
 234                         DataTable ctable = childColumns[0].Table;
 235
 236                         for (int i = 0; i < parentColumns.Length; i++) {
 237                                 DataColumn pc = parentColumns[i];
 238                                 DataColumn cc = childColumns[i];
 239
 240                                 //not null check
 241                                 if (null == pc.Table)
 242                                         throw new ArgumentException("All columns must belong to a table." +
 243                                                 " ColumnName: " + pc.ColumnName + " does not belong to a table.");
 244
 245                                 //All columns must belong to the same table
 246                                 if (ptable != pc.Table)
 247                                         throw new InvalidConstraintException("Parent columns must all belong to the same table.");
 248
 249                                 //not null check
 250                                 if (null == cc.Table)
 251                                         throw new ArgumentException("All columns must belong to a table." +
 252                                                 " ColumnName: " + pc.ColumnName + " does not belong to a table.");
 253
 254                                 //All columns must belong to the same table.
 255                                 if (ctable != cc.Table)
 256                                         throw new InvalidConstraintException("Child columns must all belong to the same table.");
 257
 258                                 if (pc.CompiledExpression != null)
 259                                         throw new ArgumentException(String.Format("Cannot create a constraint based on Expression column {0}.", pc.ColumnName));
 260
 261                                 if (cc.CompiledExpression != null)
 262                                         throw new ArgumentException(String.Format("Cannot create a constraint based on Expression column {0}.", cc.ColumnName));
 263
 264                         }
 265
 266                         //Same dataset.  If both are null it's ok
 267                         if (ptable.DataSet != ctable.DataSet)
 268                         {
 269                                 //LAMESPEC: spec says InvalidConstraintExceptoin
 270                                 //      impl does InvalidOperationException
 271                                 throw new InvalidOperationException("Parent column and child column must belong to" +
 272                                                 " tables that belong to the same DataSet.");
 273
 274                         }
 275
 276
 277                         int identicalCols = 0;
 278                         for (int i = 0; i < parentColumns.Length; i++)
 279                         {
 280                                 DataColumn pc = parentColumns[i];
 281                                 DataColumn cc = childColumns[i];
 282
 283                                 if (pc == cc) {
 284                                         identicalCols++;
 285                                         continue;
 286                                 }
 287
 288                                 if (!pc.DataTypeMatches (cc)) {
 289                                         //LAMESPEC: spec says throw InvalidConstraintException
 290                                         //              implementation throws InvalidOperationException
 291                                         throw new InvalidOperationException ("Parent column is not type compatible with it's child"
 292                                                 + " column.");
 293                                 }
 294                         }
 295                         if (identicalCols == parentColumns.Length)
 296                                 throw new InvalidOperationException ("Property not accessible because 'ParentKey and ChildKey are identical.'.");
 297
 298                 }
 299
 300                 //Checks to see if a related unique constraint exists
 301                 //if it doesn't then a unique constraint is created.
 302                 //if a unique constraint can't be created an exception will be thrown
 303                 private void _ensureUniqueConstraintExists(ConstraintCollection collection,
 304                                 DataColumn [] parentColumns)
 305                 {
 306                         //not null
 307                         if (null == parentColumns) throw new ArgumentNullException(
 308                                         "ParentColumns can't be null");
 309
 310                         UniqueConstraint uc = null;
 311
 312                         //see if unique constraint already exists
 313                         //if not create unique constraint
 314                         if(parentColumns[0] != null)
 315                                 uc = UniqueConstraint.GetUniqueConstraintForColumnSet(parentColumns[0].Table.Constraints, parentColumns);
 316
 317                         if (null == uc) {
 318                                 uc = new UniqueConstraint(parentColumns, false); //could throw
 319                                 parentColumns [0].Table.Constraints.Add (uc);
 320                         }
 321
 322                         //keep reference
 323                         _parentUniqueConstraint = uc;
 324                         _parentUniqueConstraint.ChildConstraint = this;
 325                 }
 326
 327
 328                 #endregion //Helpers
 329
 330                 #region Properties
 331
 332                 [DataCategory ("Data")]
 333                 [DefaultValue (AcceptRejectRule.None)]
 334                 public virtual AcceptRejectRule AcceptRejectRule {
 335                         get { return _acceptRejectRule; }
 336                         set { _acceptRejectRule = value; }
 337                 }
 338
 339                 [DataCategory ("Data")]
 340                 [ReadOnly (true)]
 341                 public virtual DataColumn[] Columns {
 342                         get { return _childColumns; }
 343                 }
 344
 345                 [DataCategory ("Data")]
 346                 [DefaultValue (Rule.Cascade)]
 347                 public virtual Rule DeleteRule {
 348                         get { return _deleteRule; }
 349                         set { _deleteRule = value; }
 350                 }
 351
 352                 [DataCategory ("Data")]
 353                 [DefaultValue (Rule.Cascade)]
 354                 public virtual Rule UpdateRule {
 355                         get { return _updateRule; }
 356                         set { _updateRule = value; }
 357                 }
 358
 359                 [DataCategory ("Data")]
 360                 [ReadOnly (true)]
 361                 public virtual DataColumn[] RelatedColumns {
 362                         get { return _parentColumns; }
 363                 }
 364
 365                 [DataCategory ("Data")]
 366                 [ReadOnly (true)]
 367                 public virtual DataTable RelatedTable {
 368                         get {
 369                                 if (_parentColumns != null)
 370                                         if (_parentColumns.Length > 0)
 371                                                 return _parentColumns[0].Table;
 372
 373                                 throw new InvalidOperationException ("Property not accessible because 'Object reference not set to an instance of an object'");
 374                         }
 375                 }
 376
 377                 [DataCategory ("Data")]
 378                 [ReadOnly (true)]
 379                 public override DataTable Table {
 380                         get {
 381                                 if (_childColumns != null)
 382                                         if (_childColumns.Length > 0)
 383                                                 return _childColumns[0].Table;
 384
 385                                 throw new InvalidOperationException ("Property not accessible because 'Object reference not set to an instance of an object'");
 386                         }
 387                 }
 388
 389                 internal UniqueConstraint ParentConstraint {
 390                         get { return _parentUniqueConstraint; }
 391                 }
 392
 393                 #endregion // Properties
 394
 395                 #region Methods
 396
 397                 public override bool Equals(object key)
 398                 {
 399                         ForeignKeyConstraint fkc = key as ForeignKeyConstraint;
 400                         if (null == fkc) return false;
 401
 402                         //if the fk constrains the same columns then they are equal
 403                         if (! DataColumn.AreColumnSetsTheSame( this.RelatedColumns, fkc.RelatedColumns))
 404                                 return false;
 405                         if (! DataColumn.AreColumnSetsTheSame( this.Columns, fkc.Columns) )
 406                                 return false;
 407
 408                         return true;
 409                 }
 410
 411                 public override int GetHashCode()
 412                 {
 413                         //initialize hash1 and hash2 with default hashes
 414                         //any two DIFFERENT numbers will do here
 415                         int hash1 = 32, hash2 = 88;
 416                         int i;
 417
 418                         //derive the hash code from the columns that way
 419                         //Equals and GetHashCode return Equal objects to be the
 420                         //same
 421
 422                         //Get the first parent column hash
 423                         if (this.Columns.Length > 0)
 424                                 hash1 ^= this.Columns[0].GetHashCode();
 425
 426                         //get the rest of the parent column hashes if there any
 427                         for (i = 1; i < this.Columns.Length; i++)
 428                         {
 429                                 hash1 ^= this.Columns[1].GetHashCode();
 430
 431                         }
 432
 433                         //Get the child column hash
 434                         if (this.RelatedColumns.Length > 0)
 435                                 hash2 ^= this.Columns[0].GetHashCode();
 436
 437                         for (i = 1; i < this.RelatedColumns.Length; i++)
 438                         {
 439                                 hash2 ^= this.RelatedColumns[1].GetHashCode();
 440                         }
 441
 442                         //combine the two hashes
 443                         return hash1 ^ hash2;
 444                 }
 445
 446                 internal override void AddToConstraintCollectionSetup(
 447                                 ConstraintCollection collection)
 448                 {
 449                         if (collection.Table != Table)
 450                                 throw new InvalidConstraintException("This constraint cannot be added since ForeignKey doesn't belong to table " + RelatedTable.TableName + ".");
 451
 452                         //run Ctor rules again
 453                         _validateColumns(_parentColumns, _childColumns);
 454
 455                         //we must have a unique constraint on the parent
 456                         _ensureUniqueConstraintExists(collection, _parentColumns);
 457
 458                         if ( (Table.DataSet != null && Table.DataSet.EnforceConstraints)
 459                              || (Table.DataSet == null && Table.EnforceConstraints)) {
 460                                 if (IsConstraintViolated())
 461                                         throw new ArgumentException("This constraint cannot be enabled as not all values have corresponding parent values.");
 462                         }
 463                         //FIXME : if this fails and we created a unique constraint
 464                         //we should probably roll it back
 465                         // and remove index form Table
 466                 }
 467
 468                 internal override void RemoveFromConstraintCollectionCleanup(
 469                                 ConstraintCollection collection)
 470                 {
 471                         _parentUniqueConstraint.ChildConstraint = null;
 472                         Index = null;
 473                 }
 474
 475                 internal override bool IsConstraintViolated()
 476                 {
 477                         if (Table.DataSet == null || RelatedTable.DataSet == null)
 478                                 return false;
 479
 480                         bool hasErrors = false;
 481                         foreach (DataRow row in Table.Rows) {
 482                                 if (row.RowState == DataRowState.Deleted)
 483                                         continue;
 484
 485                                 // we check if all values in _childColumns place are nulls.
 486                                 // if yes we return.
 487                                 if (row.IsNullColumns(_childColumns))
 488                                         continue;
 489
 490                                 // check whenever there is (at least one) parent row  in RelatedTable
 491                                 if(!RelatedTable.RowsExist(_parentColumns,_childColumns,row)) {
 492                                         // if no parent row exists - constraint is violated
 493                                         hasErrors = true;
 494                                         string[] values = new string[_childColumns.Length];
 495                                         for (int i = 0; i < _childColumns.Length; i++){
 496                                                 DataColumn col = _childColumns[i];
 497                                                 values[i] = row[col].ToString();
 498                                         }
 499
 500                                         row.RowError = String.Format("ForeignKeyConstraint {0} requires the child key values ({1}) to exist in the parent table.",
 501                                                 ConstraintName, String.Join(",", values));
 502                                 }
 503                         }
 504
 505                         if (hasErrors)
 506                                 //throw new ConstraintException("Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.");
 507                                 return true;
 508
 509                         return false;
 510                 }
 511
 512                 internal override void AssertConstraint(DataRow row)
 513                 {
 514                         // first we check if all values in _childColumns place are nulls.
 515                         // if yes we return.
 516                         if (row.IsNullColumns(_childColumns))
 517                                 return;
 518
 519                         // check whenever there is (at least one) parent row  in RelatedTable
 520                         if(!RelatedTable.RowsExist(_parentColumns,_childColumns,row)) {
 521                                 // if no parent row exists - constraint is violated
 522                                 throw new InvalidConstraintException(GetErrorMessage(row));
 523                         }
 524                 }
 525
 526                 internal override bool IsColumnContained(DataColumn column)
 527                 {
 528                         for (int i = 0; i < _parentColumns.Length; i++)
 529                                 if (column == _parentColumns[i])
 530                                         return true;
 531
 532                         for (int i = 0; i < _childColumns.Length; i++)
 533                                 if (column == _childColumns[i])
 534                                         return true;
 535
 536                         return false;
 537                 }
 538
 539                 internal override bool CanRemoveFromCollection(ConstraintCollection col, bool shouldThrow){
 540                         return true;
 541                 }
 542
 543                 private string GetErrorMessage(DataRow row)
 544                 {
 545                         System.Text.StringBuilder sb = new System.Text.StringBuilder();
 546                         for (int i = 0; i < _childColumns.Length; i++) {
 547                                 sb.Append(row[_childColumns[0]].ToString());
 548                                 if (i != _childColumns.Length - 1) {
 549                                         sb.Append(',');
 550                                 }
 551                         }
 552                         string valStr = sb.ToString();
 553                         return "ForeignKeyConstraint " + ConstraintName + " requires the child key values (" + valStr + ") to exist in the parent table.";
 554                 }
 555
 556                 #endregion // Methods
 557         }
 558
 559 }