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 #if !NET_2_0
  46         [Serializable]
  47 #endif
  48         public class ForeignKeyConstraint : Constraint
  49         {
  50                 private UniqueConstraint _parentUniqueConstraint;
  51                 //FIXME: create a class which will wrap this collection
  52                 private DataColumn [] _parentColumns;
  53                 //FIXME: create a class which will wrap this collection
  54                 private DataColumn [] _childColumns;
  55                 private Rule _deleteRule = Rule.Cascade;
  56                 private Rule _updateRule = Rule.Cascade;
  57                 private AcceptRejectRule _acceptRejectRule = AcceptRejectRule.None;
  58                 private string _parentTableName;
  59 #if NET_2_0
  60                 private string _parentTableNamespace;
  61 #endif
  62                 private string _childTableName;
  63
  64                 //FIXME: remove those; and use only DataColumns[]
  65                 private string [] _parentColumnNames;
  66                 private string [] _childColumnNames;
  67
  68                 #region Constructors
  69
  70                 public ForeignKeyConstraint(DataColumn parentColumn, DataColumn childColumn)
  71                 {
  72                         if (null == parentColumn || null == childColumn) {
  73                                 throw new NullReferenceException("Neither parentColumn or" +
  74                                         " childColumn can be null.");
  75                         }
  76                         _foreignKeyConstraint(null, new DataColumn[] {parentColumn},
  77                                         new DataColumn[] {childColumn});
  78                 }
  79
  80                 public ForeignKeyConstraint(DataColumn[] parentColumns, DataColumn[] childColumns)
  81                 {
  82                         _foreignKeyConstraint(null, parentColumns, childColumns);
  83                 }
  84
  85                 public ForeignKeyConstraint(string constraintName, DataColumn parentColumn, DataColumn childColumn)
  86                 {
  87                         if (null == parentColumn || null == childColumn) {
  88                                 throw new NullReferenceException("Neither parentColumn or" +
  89                                         " childColumn can be null.");
  90                         }
  91
  92                         _foreignKeyConstraint(constraintName, new DataColumn[] {parentColumn},
  93                                         new DataColumn[] {childColumn});
  94                 }
  95
  96                 public ForeignKeyConstraint(string constraintName, DataColumn[] parentColumns, DataColumn[] childColumns)
  97                 {
  98                         _foreignKeyConstraint(constraintName, parentColumns, childColumns);
  99                 }
 100
 101                 //special case
 102                 [Browsable (false)]
 103                 public ForeignKeyConstraint(string constraintName, string parentTableName, string[] parentColumnNames, string[] childColumnNames, AcceptRejectRule acceptRejectRule, Rule deleteRule, Rule updateRule)
 104                 {
 105                         InitInProgress = true;
 106                         base.ConstraintName = constraintName;
 107
 108                         // "parentTableName" is searched in the "DataSet" to which the "DataTable"
 109                         // from which AddRange() is called
 110                         // childTable is the "DataTable" which calls AddRange()
 111
 112                         // Keep reference to parentTableName to resolve later
 113                         _parentTableName = parentTableName;
 114
 115                         // Keep reference to parentColumnNames to resolve later
 116                         _parentColumnNames = parentColumnNames;
 117
 118                         // Keep reference to childColumnNames to resolve later
 119                         _childColumnNames = childColumnNames;
 120
 121                         _acceptRejectRule = acceptRejectRule;
 122                         _deleteRule = deleteRule;
 123                         _updateRule = updateRule;
 124                 }
 125
 126                 internal override void FinishInit (DataTable childTable)
 127                 {
 128                         if (childTable.DataSet == null)
 129                                 throw new InvalidConstraintException ("ChildTable : " + childTable.TableName + " does not belong to any DataSet");
 130
 131                         DataSet dataSet = childTable.DataSet;
 132                         _childTableName = childTable.TableName;
 133
 134                         if (!dataSet.Tables.Contains (_parentTableName))
 135                                 throw new InvalidConstraintException ("Table : " + _parentTableName + "does not exist in DataSet : " + dataSet);
 136
 137                         DataTable parentTable = dataSet.Tables [_parentTableName];
 138
 139                         int i = 0, j = 0;
 140
 141                         if (_parentColumnNames.Length < 0 || _childColumnNames.Length < 0)
 142                                 throw new InvalidConstraintException ("Neither parent nor child columns can be zero length");
 143
 144                         if (_parentColumnNames.Length != _childColumnNames.Length)
 145                                 throw new InvalidConstraintException ("Both parent and child columns must be of same length");
 146                         DataColumn[] parentColumns = new DataColumn [_parentColumnNames.Length];
 147                         DataColumn[] childColumns = new DataColumn [_childColumnNames.Length];
 148
 149                         foreach (string parentCol in _parentColumnNames){
 150                                 if (!parentTable.Columns.Contains (parentCol))
 151                                         throw new InvalidConstraintException ("Table : " + _parentTableName + "does not contain the column :" + parentCol);
 152                                 parentColumns [i++] = parentTable. Columns [parentCol];
 153                         }
 154
 155                         foreach (string childCol in _childColumnNames){
 156                                 if (!childTable.Columns.Contains (childCol))
 157                                         throw new InvalidConstraintException ("Table : " + _childTableName + "does not contain the column : " + childCol);
 158                                 childColumns [j++] = childTable.Columns [childCol];
 159                         }
 160                         _validateColumns (parentColumns, childColumns);
 161                         _parentColumns = parentColumns;
 162                         _childColumns = childColumns;
 163 #if NET_2_0
 164                         parentTable.Namespace = _parentTableNamespace;
 165 #endif
 166                         InitInProgress = false;
 167                 }
 168
 169 #if NET_2_0
 170                 [Browsable (false)]
 171                 public ForeignKeyConstraint (string constraintName, string parentTableName, string parentTableNamespace, string[] parentColumnNames, string[] childColumnNames, AcceptRejectRule acceptRejectRule, Rule deleteRule, Rule updateRule)
 172                 {
 173                         InitInProgress = true;
 174                         base.ConstraintName = constraintName;
 175
 176                         // "parentTableName" is searched in the "DataSet" to which the "DataTable"
 177                         // from which AddRange() is called
 178                         // childTable is the "DataTable" which calls AddRange()
 179
 180                         // Keep reference to parentTableName to resolve later
 181                         _parentTableName = parentTableName;
 182                         _parentTableNamespace = parentTableNamespace;
 183
 184                         // Keep reference to parentColumnNames to resolve later
 185                         _parentColumnNames = parentColumnNames;
 186
 187                         // Keep reference to childColumnNames to resolve later
 188                         _childColumnNames = childColumnNames;
 189
 190                         _acceptRejectRule = acceptRejectRule;
 191                         _deleteRule = deleteRule;
 192                         _updateRule = updateRule;
 193                 }
 194 #endif
 195
 196                 private void _foreignKeyConstraint(string constraintName, DataColumn[] parentColumns,
 197                                 DataColumn[] childColumns)
 198                 {
 199
 200                         //Validate
 201                         _validateColumns(parentColumns, childColumns);
 202
 203                         //Set Constraint Name
 204                         base.ConstraintName = constraintName;
 205
 206                         //Keep reference to columns
 207                         _parentColumns = parentColumns;
 208                         _childColumns = childColumns;
 209                 }
 210
 211 #endregion // Constructors
 212
 213 #region Helpers
 214
 215                 private void _validateColumns(DataColumn[] parentColumns, DataColumn[] childColumns)
 216                 {
 217                         //not null
 218                         if (null == parentColumns || null == childColumns)
 219                                 throw new ArgumentNullException();
 220
 221                         //at least one element in each array
 222                         if (parentColumns.Length < 1 || childColumns.Length < 1)
 223                                 throw new ArgumentException("Neither ParentColumns or ChildColumns can't be" +
 224                                                 " zero length.");
 225
 226                         //same size arrays
 227                         if (parentColumns.Length != childColumns.Length)
 228                                 throw new ArgumentException("Parent columns and child columns must be the same length.");
 229
 230
 231                         DataTable ptable = parentColumns[0].Table;
 232                         DataTable ctable = childColumns[0].Table;
 233
 234                         for (int i = 0; i < parentColumns.Length; i++) {
 235                                 DataColumn pc = parentColumns[i];
 236                                 DataColumn cc = childColumns[i];
 237
 238                                 //not null check
 239                                 if (null == pc.Table)
 240                                         throw new ArgumentException("All columns must belong to a table." +
 241                                                 " ColumnName: " + pc.ColumnName + " does not belong to a table.");
 242
 243                                 //All columns must belong to the same table
 244                                 if (ptable != pc.Table)
 245                                         throw new InvalidConstraintException("Parent columns must all belong to the same table.");
 246
 247                                 //not null check
 248                                 if (null == cc.Table)
 249                                         throw new ArgumentException("All columns must belong to a table." +
 250                                                 " ColumnName: " + pc.ColumnName + " does not belong to a table.");
 251
 252                                 //All columns must belong to the same table.
 253                                 if (ctable != cc.Table)
 254                                         throw new InvalidConstraintException("Child columns must all belong to the same table.");
 255
 256                                 if (pc.CompiledExpression != null)
 257                                         throw new ArgumentException(String.Format("Cannot create a constraint based on Expression column {0}.", pc.ColumnName));
 258
 259                                 if (cc.CompiledExpression != null)
 260                                         throw new ArgumentException(String.Format("Cannot create a constraint based on Expression column {0}.", cc.ColumnName));
 261
 262                         }
 263
 264                         //Same dataset.  If both are null it's ok
 265                         if (ptable.DataSet != ctable.DataSet)
 266                         {
 267                                 //LAMESPEC: spec says InvalidConstraintExceptoin
 268                                 //      impl does InvalidOperationException
 269                                 throw new InvalidOperationException("Parent column and child column must belong to" +
 270                                                 " tables that belong to the same DataSet.");
 271
 272                         }
 273
 274
 275                         int identicalCols = 0;
 276                         for (int i = 0; i < parentColumns.Length; i++)
 277                         {
 278                                 DataColumn pc = parentColumns[i];
 279                                 DataColumn cc = childColumns[i];
 280
 281                                 if (pc == cc) {
 282                                         identicalCols++;
 283                                         continue;
 284                                 }
 285
 286                                 if (!pc.DataTypeMatches (cc)) {
 287                                         //LAMESPEC: spec says throw InvalidConstraintException
 288                                         //              implementation throws InvalidOperationException
 289                                         throw new InvalidOperationException ("Parent column is not type compatible with it's child"
 290                                                 + " column.");
 291                                 }
 292                         }
 293                         if (identicalCols == parentColumns.Length)
 294                                 throw new InvalidOperationException ("Property not accessible because 'ParentKey and ChildKey are identical.'.");
 295
 296                 }
 297
 298                 //Checks to see if a related unique constraint exists
 299                 //if it doesn't then a unique constraint is created.
 300                 //if a unique constraint can't be created an exception will be thrown
 301                 private void _ensureUniqueConstraintExists(ConstraintCollection collection,
 302                                 DataColumn [] parentColumns)
 303                 {
 304                         //not null
 305                         if (null == parentColumns) throw new ArgumentNullException(
 306                                         "ParentColumns can't be null");
 307
 308                         UniqueConstraint uc = null;
 309
 310                         //see if unique constraint already exists
 311                         //if not create unique constraint
 312                         if(parentColumns[0] != null)
 313                                 uc = UniqueConstraint.GetUniqueConstraintForColumnSet(parentColumns[0].Table.Constraints, parentColumns);
 314
 315                         if (null == uc) {
 316                                 uc = new UniqueConstraint(parentColumns, false); //could throw
 317                                 parentColumns [0].Table.Constraints.Add (uc);
 318                         }
 319
 320                         //keep reference
 321                         _parentUniqueConstraint = uc;
 322                         _parentUniqueConstraint.ChildConstraint = this;
 323                 }
 324
 325
 326                 #endregion //Helpers
 327
 328                 #region Properties
 329
 330                 [DataCategory ("Data")]
 331 #if !NET_2_0
 332                 [DataSysDescription ("For accept and reject changes, indicates what kind of cascading should take place across this relation.")]
 333 #endif
 334                 [DefaultValue (AcceptRejectRule.None)]
 335                 public virtual AcceptRejectRule AcceptRejectRule {
 336                         get { return _acceptRejectRule; }
 337                         set { _acceptRejectRule = value; }
 338                 }
 339
 340                 [DataCategory ("Data")]
 341 #if !NET_2_0
 342                 [DataSysDescription ("Indicates the child columns of this constraint.")]
 343 #endif
 344                 [ReadOnly (true)]
 345                 public virtual DataColumn[] Columns {
 346                         get { return _childColumns; }
 347                 }
 348
 349                 [DataCategory ("Data")]
 350 #if !NET_2_0
 351                 [DataSysDescription ("For deletions, indicates what kind of cascading should take place across this relation.")]
 352 #endif
 353                 [DefaultValue (Rule.Cascade)]
 354                 public virtual Rule DeleteRule {
 355                         get { return _deleteRule; }
 356                         set { _deleteRule = value; }
 357                 }
 358
 359                 [DataCategory ("Data")]
 360 #if !NET_2_0
 361                 [DataSysDescription ("For updates, indicates what kind of cascading should take place across this relation.")]
 362 #endif
 363                 [DefaultValue (Rule.Cascade)]
 364                 public virtual Rule UpdateRule {
 365                         get { return _updateRule; }
 366                         set { _updateRule = value; }
 367                 }
 368
 369                 [DataCategory ("Data")]
 370 #if !NET_2_0
 371                 [DataSysDescription ("Indicates the parent columns of this constraint.")]
 372 #endif
 373                 [ReadOnly (true)]
 374                 public virtual DataColumn[] RelatedColumns {
 375                         get { return _parentColumns; }
 376                 }
 377
 378                 [DataCategory ("Data")]
 379 #if !NET_2_0
 380                 [DataSysDescription ("Indicates the child table of this constraint.")]
 381 #endif
 382                 [ReadOnly (true)]
 383                 public virtual DataTable RelatedTable {
 384                         get {
 385                                 if (_parentColumns != null)
 386                                         if (_parentColumns.Length > 0)
 387                                                 return _parentColumns[0].Table;
 388
 389                                 throw new InvalidOperationException ("Property not accessible because 'Object reference not set to an instance of an object'");
 390                         }
 391                 }
 392
 393                 [DataCategory ("Data")]
 394 #if !NET_2_0
 395                 [DataSysDescription ("Indicates the table of this constraint.")]
 396 #endif
 397                 [ReadOnly (true)]
 398                 public override DataTable Table {
 399                         get {
 400                                 if (_childColumns != null)
 401                                         if (_childColumns.Length > 0)
 402                                                 return _childColumns[0].Table;
 403
 404                                 throw new InvalidOperationException ("Property not accessible because 'Object reference not set to an instance of an object'");
 405                         }
 406                 }
 407
 408                 internal UniqueConstraint ParentConstraint {
 409                         get { return _parentUniqueConstraint; }
 410                 }
 411
 412                 #endregion // Properties
 413
 414                 #region Methods
 415
 416                 public override bool Equals(object key)
 417                 {
 418                         ForeignKeyConstraint fkc = key as ForeignKeyConstraint;
 419                         if (null == fkc) return false;
 420
 421                         //if the fk constrains the same columns then they are equal
 422                         if (! DataColumn.AreColumnSetsTheSame( this.RelatedColumns, fkc.RelatedColumns))
 423                                 return false;
 424                         if (! DataColumn.AreColumnSetsTheSame( this.Columns, fkc.Columns) )
 425                                 return false;
 426
 427                         return true;
 428                 }
 429
 430                 public override int GetHashCode()
 431                 {
 432                         //initialize hash1 and hash2 with default hashes
 433                         //any two DIFFERENT numbers will do here
 434                         int hash1 = 32, hash2 = 88;
 435                         int i;
 436
 437                         //derive the hash code from the columns that way
 438                         //Equals and GetHashCode return Equal objects to be the
 439                         //same
 440
 441                         //Get the first parent column hash
 442                         if (this.Columns.Length > 0)
 443                                 hash1 ^= this.Columns[0].GetHashCode();
 444
 445                         //get the rest of the parent column hashes if there any
 446                         for (i = 1; i < this.Columns.Length; i++)
 447                         {
 448                                 hash1 ^= this.Columns[1].GetHashCode();
 449
 450                         }
 451
 452                         //Get the child column hash
 453                         if (this.RelatedColumns.Length > 0)
 454                                 hash2 ^= this.Columns[0].GetHashCode();
 455
 456                         for (i = 1; i < this.RelatedColumns.Length; i++)
 457                         {
 458                                 hash2 ^= this.RelatedColumns[1].GetHashCode();
 459                         }
 460
 461                         //combine the two hashes
 462                         return hash1 ^ hash2;
 463                 }
 464
 465                 internal override void AddToConstraintCollectionSetup(
 466                                 ConstraintCollection collection)
 467                 {
 468                         if (collection.Table != Table)
 469                                 throw new InvalidConstraintException("This constraint cannot be added since ForeignKey doesn't belong to table " + RelatedTable.TableName + ".");
 470
 471                         //run Ctor rules again
 472                         _validateColumns(_parentColumns, _childColumns);
 473
 474                         //we must have a unique constraint on the parent
 475                         _ensureUniqueConstraintExists(collection, _parentColumns);
 476
 477                         if ( (Table.DataSet != null && Table.DataSet.EnforceConstraints)
 478                              || (Table.DataSet == null && Table.EnforceConstraints)) {
 479                                 if (IsConstraintViolated())
 480                                         throw new ArgumentException("This constraint cannot be enabled as not all values have corresponding parent values.");
 481                         }
 482                         //FIXME : if this fails and we created a unique constraint
 483                         //we should probably roll it back
 484                         // and remove index form Table
 485                 }
 486
 487                 internal override void RemoveFromConstraintCollectionCleanup(
 488                                 ConstraintCollection collection)
 489                 {
 490                         _parentUniqueConstraint.ChildConstraint = null;
 491                         Index = null;
 492                 }
 493
 494                 internal override bool IsConstraintViolated()
 495                 {
 496                         if (Table.DataSet == null || RelatedTable.DataSet == null)
 497                                 return false;
 498
 499                         bool hasErrors = false;
 500                         foreach (DataRow row in Table.Rows) {
 501                                 // first we check if all values in _childColumns place are nulls.
 502                                 // if yes we return.
 503                                 if (row.IsNullColumns(_childColumns))
 504                                         continue;
 505
 506                                 // check whenever there is (at least one) parent row  in RelatedTable
 507                                 if(!RelatedTable.RowsExist(_parentColumns,_childColumns,row)) {
 508                                         // if no parent row exists - constraint is violated
 509                                         hasErrors = true;
 510                                         string[] values = new string[_childColumns.Length];
 511                                         for (int i = 0; i < _childColumns.Length; i++){
 512                                                 DataColumn col = _childColumns[i];
 513                                                 values[i] = row[col].ToString();
 514                                         }
 515
 516                                         row.RowError = String.Format("ForeignKeyConstraint {0} requires the child key values ({1}) to exist in the parent table.",
 517                                                 ConstraintName, String.Join(",", values));
 518                                 }
 519                         }
 520
 521                         if (hasErrors)
 522                                 //throw new ConstraintException("Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.");
 523                                 return true;
 524
 525                         return false;
 526                 }
 527
 528                 internal override void AssertConstraint(DataRow row)
 529                 {
 530                         // first we check if all values in _childColumns place are nulls.
 531                         // if yes we return.
 532                         if (row.IsNullColumns(_childColumns))
 533                                 return;
 534
 535                         // check whenever there is (at least one) parent row  in RelatedTable
 536                         if(!RelatedTable.RowsExist(_parentColumns,_childColumns,row)) {
 537                                 // if no parent row exists - constraint is violated
 538                                 throw new InvalidConstraintException(GetErrorMessage(row));
 539                         }
 540                 }
 541
 542                 internal override bool IsColumnContained(DataColumn column)
 543                 {
 544                         for (int i = 0; i < _parentColumns.Length; i++)
 545                                 if (column == _parentColumns[i])
 546                                         return true;
 547
 548                         for (int i = 0; i < _childColumns.Length; i++)
 549                                 if (column == _childColumns[i])
 550                                         return true;
 551
 552                         return false;
 553                 }
 554
 555                 internal override bool CanRemoveFromCollection(ConstraintCollection col, bool shouldThrow){
 556                         return true;
 557                 }
 558
 559                 private string GetErrorMessage(DataRow row)
 560                 {
 561                         System.Text.StringBuilder sb = new System.Text.StringBuilder();
 562                         for (int i = 0; i < _childColumns.Length; i++) {
 563                                 sb.Append(row[_childColumns[0]].ToString());
 564                                 if (i != _childColumns.Length - 1) {
 565                                         sb.Append(',');
 566                                 }
 567                         }
 568                         string valStr = sb.ToString();
 569                         return "ForeignKeyConstraint " + ConstraintName + " requires the child key values (" + valStr + ") to exist in the parent table.";
 570                 }
 571
 572                 #endregion // Methods
 573         }
 574
 575 }