mcs/class/System.Data/System.Data/DataSet.cs

   1 //
   2 // System.Data/DataSet.cs
   3 //
   4 // Author:
   5 //   Christopher Podurgiel <cpodurgiel@msn.com>
   6 //   Daniel Morgan <danmorg@sc.rr.com>
   7 //   Rodrigo Moya <rodrigo@ximian.com>
   8 //   Stuart Caborn <stuart.caborn@virgin.net>
   9 //   Tim Coleman (tim@timcoleman.com)
  10 //   Ville Palo <vi64pa@koti.soon.fi>
  11 //
  12 // (C) Ximian, Inc. 2002
  13 // Copyright (C) Tim Coleman, 2002
  14 //
  15
  16 using System;
  17 using System.Collections;
  18 using System.ComponentModel;
  19 using System.Globalization;
  20 using System.Threading;
  21 using System.IO;
  22 using System.Runtime.Serialization;
  23 using System.Xml;
  24 using System.Xml.Schema;
  25
  26 namespace System.Data {
  27         /// <summary>
  28         /// an in-memory cache of data
  29         /// </summary>
  30         //[Designer]
  31         [ToolboxItem (false)]
  32         [DefaultProperty ("DataSetName")]
  33         [Serializable]
  34         public class DataSet : MarshalByValueComponent, IListSource,
  35                 ISupportInitialize, ISerializable {
  36                 private string dataSetName;
  37                 private string _namespace = "";
  38                 private string prefix;
  39                 private bool caseSensitive;
  40                 private bool enforceConstraints = true;
  41                 private DataTableCollection tableCollection;
  42                 private DataRelationCollection relationCollection;
  43                 private PropertyCollection properties;
  44                 private DataViewManager defaultView;
  45                 private CultureInfo locale;
  46
  47                 #region Constructors
  48
  49                 public DataSet() : this ("NewDataSet") {
  50                 }
  51
  52                 public DataSet(string name) {
  53                         dataSetName = name;
  54                         tableCollection = new DataTableCollection (this);
  55                         relationCollection = new DataRelationCollection.DataSetRelationCollection (this);
  56                         properties = new PropertyCollection();
  57                 }
  58
  59                 [MonoTODO]
  60                 protected DataSet(SerializationInfo info, StreamingContext context) : this () {
  61                         throw new NotImplementedException ();
  62                 }
  63
  64                 #endregion // Constructors
  65
  66                 #region Public Properties
  67
  68                 [DataCategory ("Data")]
  69                 [DataSysDescription ("Indicates whether comparing strings within the DataSet is case sensitive.")]
  70                 [DefaultValue (false)]
  71                 public bool CaseSensitive {
  72                         get { return caseSensitive; }
  73                         set {
  74                                 foreach (DataTable T in Tables) {
  75                                         if (T.VirginCaseSensitive)
  76                                                 T.CaseSensitive = value;
  77                                 }
  78
  79                                 caseSensitive = value;
  80                         }
  81                 }
  82
  83                 [DataCategory ("Data")]
  84                 [DataSysDescription ("The name of this DataSet.")]
  85                 [DefaultValue ("")]
  86                 public string DataSetName {
  87                         get { return dataSetName; }
  88                         set { dataSetName = value; }
  89                 }
  90
  91                 [DataSysDescription ("Indicates a custom \"view\" of the data contained by the DataSet. This view allows filtering, searching, and navigating through the custom data view.")]
  92                 [Browsable (false)]
  93                 public DataViewManager DefaultViewManager {
  94                         get {
  95                                 if (defaultView == null)
  96                                         defaultView = new DataViewManager (this);
  97                                 return defaultView;
  98                         }
  99                 }
 100
 101                 [DataSysDescription ("Indicates whether constraint rules are to be followed.")]
 102                 [DefaultValue (true)]
 103                 public bool EnforceConstraints {
 104                         get { return enforceConstraints; }
 105                         set { enforceConstraints = value; }
 106                 }
 107
 108                 [Browsable (false)]
 109                 [DataCategory ("Data")]
 110                 [DataSysDescription ("The collection that holds custom user information.")]
 111                 public PropertyCollection ExtendedProperties {
 112                         get { return properties; }
 113                 }
 114
 115                 [Browsable (false)]
 116                 [DataSysDescription ("Indicates that the DataSet has errors.")]
 117                 public bool HasErrors {
 118                         [MonoTODO]
 119                         get {
 120                                 throw new NotImplementedException ();
 121                         }
 122                 }
 123
 124                 [DataCategory ("Data")]
 125                 [DataSysDescription ("Indicates a locale under which to compare strings within the DataSet.")]
 126                 public CultureInfo Locale {
 127                         get {
 128                                 return locale;
 129                         }
 130                         set {
 131                                 if (locale == null || !locale.Equals(value)) {
 132                                         // TODO: check if the new locale is valid
 133                                         // TODO: update locale of all tables
 134                                         locale = value;
 135                                 }
 136                         }
 137                 }
 138
 139                 public void Merge (DataRow[] rows)
 140                 {
 141                         Merge (rows, false, MissingSchemaAction.Add);
 142                 }
 143
 144                 public void Merge (DataSet dataSet)
 145                 {
 146                         Merge (dataSet, false, MissingSchemaAction.Add);
 147                 }
 148
 149                 public void Merge (DataTable table)
 150                 {
 151                         Merge (table, false, MissingSchemaAction.Add);
 152                 }
 153
 154                 public void Merge (DataSet dataSet, bool preserveChanges)
 155                 {
 156                         Merge (dataSet, preserveChanges, MissingSchemaAction.Add);
 157                 }
 158
 159                 [MonoTODO]
 160                 public void Merge (DataRow[] rows, bool preserveChanges, MissingSchemaAction missingSchemaAction)
 161                 {
 162                         throw new NotImplementedException();
 163                 }
 164
 165                 [MonoTODO]
 166                 public void Merge (DataSet dataSet, bool preserveChanges, MissingSchemaAction missingSchemaAction)
 167                 {
 168                         throw new NotImplementedException();
 169                 }
 170
 171                 [MonoTODO]
 172                 public void Merge (DataTable table, bool preserveChanges, MissingSchemaAction missingSchemaAction)
 173                 {
 174                         throw new NotImplementedException();
 175                 }
 176
 177                 [DataCategory ("Data")]
 178                 [DataSysDescription ("Indicates the XML uri namespace for the root element pointed at by this DataSet.")]
 179                 [DefaultValue ("")]
 180                 public string Namespace {
 181                         [MonoTODO]
 182                         get { return _namespace; }
 183                         [MonoTODO]
 184                         set {
 185                                 //TODO - trigger an event if this happens?
 186                                 _namespace = value;
 187                         }
 188                 }
 189
 190                 [DataCategory ("Data")]
 191                 [DataSysDescription ("Indicates the prefix of the namespace used for this DataSet.")]
 192                 [DefaultValue ("")]
 193                 public string Prefix {
 194                         [MonoTODO]
 195                         get { return prefix; }
 196                         [MonoTODO]
 197                         set {
 198                                 //TODO - trigger an event if this happens?
 199                                 prefix = value;
 200                         }
 201                 }
 202
 203                 [DataCategory ("Data")]
 204                 [DataSysDescription ("The collection that holds the relations for this DatSet.")]
 205                 [DesignerSerializationVisibility (DesignerSerializationVisibility.Content)]
 206                 public DataRelationCollection Relations {
 207                         get {
 208                                 return relationCollection;
 209                         }
 210                 }
 211
 212                 [Browsable (false)]
 213                 [DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
 214                 public override ISite Site {
 215                         [MonoTODO]
 216                         get {
 217                                 throw new NotImplementedException ();
 218                         }
 219
 220                         [MonoTODO]
 221                         set {
 222                                 throw new NotImplementedException ();
 223                         }
 224                 }
 225
 226                 [DataCategory ("Data")]
 227                 [DataSysDescription ("The collection that holds the tables for this DataSet.")]
 228                 [DesignerSerializationVisibility (DesignerSerializationVisibility.Content)]
 229                 public DataTableCollection Tables {
 230                         get { return tableCollection; }
 231                 }
 232
 233                 #endregion // Public Properties
 234
 235                 #region Public Methods
 236
 237                 [MonoTODO]
 238                 public void AcceptChanges()
 239                 {
 240                         foreach (DataTable tempTable in tableCollection)
 241                                 tempTable.AcceptChanges ();
 242                 }
 243
 244                 public void Clear()
 245                 {
 246                         throw new NotImplementedException ();
 247                 }
 248
 249                 public virtual DataSet Clone()
 250                 {
 251                         DataSet Copy = new DataSet ();
 252                         CopyProperties (Copy);
 253
 254                         foreach (DataTable Table in Tables) {
 255                                 Copy.Tables.Add (Table.Clone ());
 256                         }
 257
 258                         return Copy;
 259                 }
 260
 261                 // Copies both the structure and data for this DataSet.
 262                 public DataSet Copy()
 263                 {
 264                         DataSet Copy = new DataSet ();
 265                         CopyProperties (Copy);
 266
 267                         // Copy DatSet's tables
 268                         foreach (DataTable Table in Tables) {
 269                                 Copy.Tables.Add (Table.Copy ());
 270                         }
 271
 272                         return Copy;
 273                 }
 274
 275                 [MonoTODO]
 276                 private void CopyProperties (DataSet Copy)
 277                 {
 278                         Copy.CaseSensitive = CaseSensitive;
 279                         //Copy.Container = Container
 280                         Copy.DataSetName = DataSetName;
 281                         //Copy.DefaultViewManager
 282                         //Copy.DesignMode
 283                         Copy.EnforceConstraints = EnforceConstraints;
 284                         //Copy.ExtendedProperties
 285                         //Copy.HasErrors
 286                         //Copy.Locale = Locale;
 287                         Copy.Namespace = Namespace;
 288                         Copy.Prefix = Prefix;
 289                         //Copy.Relations = Relations;
 290                         //Copy.Site = Site;
 291
 292                 }
 293
 294                 public DataSet GetChanges()
 295                 {
 296                         throw new NotImplementedException ();
 297                 }
 298
 299
 300                 public DataSet GetChanges(DataRowState rowStates)
 301                 {
 302                         throw new NotImplementedException ();
 303                 }
 304
 305                 public string GetXml()
 306                 {
 307                         StringWriter Writer = new StringWriter ();
 308                         WriteXml (Writer, XmlWriteMode.IgnoreSchema);
 309                         return Writer.ToString ();
 310                 }
 311
 312                 public string GetXmlSchema()
 313                 {
 314                         StringWriter Writer = new StringWriter ();
 315                         WriteXmlSchema (Writer);
 316                         return Writer.ToString ();
 317                 }
 318
 319                 [MonoTODO]
 320                 public bool HasChanges()
 321                 {
 322                         throw new NotImplementedException ();
 323                 }
 324
 325                 [MonoTODO]
 326                 public bool HasChanges(DataRowState rowState)
 327                 {
 328                         throw new NotImplementedException ();
 329                 }
 330
 331                 [MonoTODO]
 332                 public void InferXmlSchema(XmlReader reader, string[] nsArray)
 333                 {
 334                 }
 335
 336                 public void InferXmlSchema(Stream stream, string[] nsArray)
 337                 {
 338                         InferXmlSchema (new XmlTextReader(stream), nsArray);
 339                 }
 340
 341                 public void InferXmlSchema(TextReader reader, string[] nsArray)
 342                 {
 343                         InferXmlSchema (new XmlTextReader(reader), nsArray);
 344                 }
 345
 346                 public void InferXmlSchema(string fileName, string[] nsArray)
 347                 {
 348                         XmlTextReader reader = new XmlTextReader(fileName);
 349                         try {
 350                                 InferXmlSchema (reader, nsArray);
 351                         } finally {
 352                                 reader.Close ();
 353                         }
 354                 }
 355
 356                 public virtual void RejectChanges()
 357                 {
 358                         throw new NotImplementedException ();
 359                 }
 360
 361                 public virtual void Reset()
 362                 {
 363                         throw new NotImplementedException ();
 364                 }
 365
 366                 public void WriteXml(Stream stream)
 367                 {
 368                         XmlWriter writer = new XmlTextWriter(stream, null );
 369
 370                         WriteXml( writer );
 371                 }
 372
 373                 ///<summary>
 374                 /// Writes the current data for the DataSet to the specified file.
 375                 /// </summary>
 376                 /// <param name="filename">Fully qualified filename to write to</param>
 377                 public void WriteXml(string fileName)
 378                 {
 379                         XmlWriter writer = new XmlTextWriter(fileName, null );
 380
 381                         WriteXml( writer );
 382                 }
 383
 384                 public void WriteXml(TextWriter writer)
 385                 {
 386                         XmlWriter xwriter = new XmlTextWriter(writer );
 387
 388                         WriteXml( xwriter );
 389                 }
 390
 391                 public void WriteXml(XmlWriter writer)
 392                 {
 393                         WriteXml( writer, XmlWriteMode.IgnoreSchema );
 394                 }
 395
 396                 public void WriteXml(Stream stream, XmlWriteMode mode)
 397                 {
 398                         XmlWriter writer = new XmlTextWriter(stream, null );
 399
 400                         WriteXml( writer, mode );
 401                 }
 402
 403                 public void WriteXml(string fileName, XmlWriteMode mode)
 404                 {
 405                         XmlWriter writer = new XmlTextWriter(fileName, null );
 406
 407                         WriteXml( writer, mode );
 408                 }
 409
 410                 public void WriteXml(TextWriter writer, XmlWriteMode mode)
 411                 {
 412                         XmlWriter xwriter = new XmlTextWriter(writer);
 413
 414                         WriteXml( xwriter, mode );
 415                 }
 416
 417                 public void WriteXml(XmlWriter writer, XmlWriteMode mode)
 418                 {
 419                         ((XmlTextWriter)writer).Formatting = Formatting.Indented;
 420                         WriteStartElement( writer, mode, Namespace, Prefix, DataSetName );
 421
 422                         if( mode == XmlWriteMode.WriteSchema )
 423                         {
 424                                 DoWriteXmlSchema( writer );
 425                         }
 426
 427                         //Write out each table in order, providing it is not
 428                         //part of another table structure via a nested parent relationship
 429                         foreach( DataTable table in Tables )
 430                         {
 431                                 bool isTopLevel = true;
 432                                 foreach( DataRelation rel in table.ParentRelations )
 433                                 {
 434                                         if( rel.Nested )
 435                                         {
 436                                                 isTopLevel = false;
 437                                                 break;
 438                                         }
 439                                 }
 440
 441                                 if( isTopLevel )
 442                                 {
 443                                         WriteTable(  writer, table, mode );
 444                                 }
 445                         }
 446
 447                         writer.WriteEndElement();
 448                 }
 449
 450                 public void WriteXmlSchema(Stream stream)
 451                 {
 452                         XmlWriter writer = new XmlTextWriter(stream, null  );
 453
 454                         WriteXmlSchema( writer );
 455                 }
 456
 457                 public void WriteXmlSchema(string fileName)
 458                 {
 459                         XmlWriter writer = new XmlTextWriter( fileName, null );
 460
 461                         WriteXmlSchema( writer );
 462                 }
 463
 464                 public void WriteXmlSchema(TextWriter writer)
 465                 {
 466                         XmlWriter xwriter = new XmlTextWriter( writer );
 467
 468                         WriteXmlSchema( xwriter );
 469                 }
 470
 471                 public void WriteXmlSchema(XmlWriter writer)
 472                 {
 473                         ((XmlTextWriter)writer).Formatting = Formatting.Indented;
 474                         //Create a skeleton doc and then write the schema
 475                         //proper which is common to the WriteXml method in schema mode
 476                         writer.WriteStartDocument();
 477
 478                         DoWriteXmlSchema( writer );
 479
 480                         writer.WriteEndDocument();
 481                 }
 482
 483                 public void ReadXmlSchema(Stream stream)
 484                 {
 485                         XmlReader reader = new XmlTextReader( stream, null );
 486                         ReadXmlSchema( reader);
 487                 }
 488
 489                 public void ReadXmlSchema(string str)
 490                 {
 491                         XmlReader reader = new XmlTextReader( str );
 492                         ReadXmlSchema( reader );
 493                 }
 494
 495                 public void ReadXmlSchema(TextReader treader)
 496                 {
 497                         XmlReader reader = new XmlTextReader( treader );
 498                         ReadXmlSchema( reader );
 499                 }
 500
 501                 public void ReadXmlSchema(XmlReader reader)
 502                 {
 503                         XmlSchemaMapper SchemaMapper = new XmlSchemaMapper (this);
 504                         SchemaMapper.Read (reader);
 505                 }
 506
 507                 public XmlReadMode ReadXml (Stream stream)
 508                 {
 509                         return ReadXml (new XmlTextReader (stream));
 510                 }
 511
 512                 public XmlReadMode ReadXml (string str)
 513                 {
 514                         return ReadXml (new XmlTextReader (str));
 515                 }
 516
 517                 public XmlReadMode ReadXml (TextReader reader)
 518                 {
 519                         return ReadXml (new XmlTextReader (reader));
 520                 }
 521
 522                 public XmlReadMode ReadXml (XmlReader r)
 523                 {
 524                         XmlDataLoader Loader = new XmlDataLoader (this);
 525                         // FIXME: somekinda exception?
 526                         if (!r.Read ())
 527                                 return XmlReadMode.Auto; // FIXME
 528
 529                         /*\
 530                          *  If document is diffgram we will use diffgram
 531                         \*/
 532                         if (r.LocalName == "diffgram")
 533                                 return ReadXml (r, XmlReadMode.DiffGram);
 534
 535                         /*\
 536                          *  If we already have a schema, or the document
 537                          *  contains an in-line schema, sets XmlReadMode to ReadSchema.
 538                         \*/
 539
 540                         // FIXME: is this always true: "if we have tables we have to have schema also"
 541                         if (Tables.Count > 0)
 542                                 return ReadXml (r, XmlReadMode.ReadSchema);
 543
 544                         /*\
 545                          *  If we dont have a schema yet and document
 546                          *  contains no inline-schema  mode is XmlReadMode.InferSchema
 547                         \*/
 548
 549                         return ReadXml (r, XmlReadMode.InferSchema);
 550
 551                 }
 552
 553                 public XmlReadMode ReadXml (Stream stream, XmlReadMode mode)
 554                 {
 555                         return ReadXml (new XmlTextReader (stream), mode);
 556                 }
 557
 558                 public XmlReadMode ReadXml (string str, XmlReadMode mode)
 559                 {
 560                         return ReadXml (new XmlTextReader (str), mode);
 561                 }
 562
 563                 public XmlReadMode ReadXml (TextReader reader, XmlReadMode mode)
 564                 {
 565                         return ReadXml (new XmlTextReader (reader), mode);
 566                 }
 567
 568                 [MonoTODO]
 569                 public XmlReadMode ReadXml (XmlReader reader, XmlReadMode mode)
 570                 {
 571                         XmlReadMode Result = XmlReadMode.Auto;
 572
 573                         if (mode == XmlReadMode.DiffGram) {
 574                                 XmlDiffLoader DiffLoader = new XmlDiffLoader (this);
 575                                 DiffLoader.Load (reader);
 576                                 Result =  XmlReadMode.DiffGram;
 577                         }
 578                         else {
 579                                 XmlDataLoader Loader = new XmlDataLoader (this);
 580                                 Result = Loader.LoadData (reader, mode);
 581                         }
 582
 583                         return Result;
 584                 }
 585
 586                 #endregion // Public Methods
 587
 588                 #region Public Events
 589
 590                 [DataCategory ("Action")]
 591                 [DataSysDescription ("Occurs when it is not possible to merge schemas for two tables with the same name.")]
 592                 public event MergeFailedEventHandler MergeFailed;
 593
 594                 #endregion // Public Events
 595
 596                 #region Destructors
 597
 598                 ~DataSet()
 599                 {
 600                 }
 601
 602                 #endregion Destructors
 603
 604                 #region IListSource methods
 605                 IList IListSource.GetList ()
 606                 {
 607                         return DefaultViewManager;
 608                 }
 609
 610                 bool IListSource.ContainsListCollection {
 611                         get {
 612                                 return true;
 613                         }
 614                 }
 615                 #endregion IListSource methods
 616
 617                 #region ISupportInitialize methods
 618                 public void BeginInit ()
 619                 {
 620                         throw new NotImplementedException ();
 621                 }
 622
 623                 public void EndInit ()
 624                 {
 625                         throw new NotImplementedException ();
 626                 }
 627                 #endregion
 628
 629                 #region ISerializable
 630                 void ISerializable.GetObjectData (SerializationInfo si, StreamingContext sc)
 631                 {
 632                         throw new NotImplementedException ();
 633                 }
 634                 #endregion
 635
 636                 #region Protected Methods
 637                 protected void GetSerializationData(SerializationInfo info, StreamingContext context)
 638                 {
 639                         string s = info.GetValue ("XmlDiffGram", typeof (String)) as String;
 640                         if (s != null) ReadXmlSerializable (new XmlTextReader(new StringReader(s)));
 641                 }
 642
 643
 644                 protected virtual System.Xml.Schema.XmlSchema GetSchemaSerializable()
 645                 {
 646                         return null; // FIXME
 647                 }
 648
 649                 protected virtual void ReadXmlSerializable(XmlReader reader)
 650                 {
 651                         ReadXml(reader, XmlReadMode.DiffGram); // FIXME
 652                 }
 653
 654                 protected virtual bool ShouldSerializeRelations ()
 655                 {
 656                         return true;
 657                 }
 658
 659                 protected virtual bool ShouldSerializeTables ()
 660                 {
 661                         return true;
 662                 }
 663
 664                 [MonoTODO]
 665                 protected internal virtual void OnPropertyChanging (PropertyChangedEventArgs pcevent)
 666                 {
 667                 }
 668
 669                 [MonoTODO]
 670                 protected virtual void OnRemoveRelation (DataRelation relation)
 671                 {
 672                 }
 673
 674                 [MonoTODO]
 675                 protected virtual void OnRemoveTable (DataTable table)
 676                 {
 677                 }
 678
 679                 [MonoTODO]
 680                 protected internal void RaisePropertyChanging (string name)
 681                 {
 682                 }
 683                 #endregion
 684
 685                 #region Private Xml Serialisation
 686
 687                 private string WriteObjectXml( object o ) {
 688                         switch (Type.GetTypeCode (o.GetType ())) {
 689                         case TypeCode.Boolean:
 690                                 return XmlConvert.ToString ((Boolean) o);
 691                         case TypeCode.Byte:
 692                                 return XmlConvert.ToString ((Byte) o);
 693                         case TypeCode.Char:
 694                                 return XmlConvert.ToString ((Char) o);
 695                         case TypeCode.DateTime:
 696                                 return XmlConvert.ToString ((DateTime) o);
 697                         case TypeCode.Decimal:
 698                                 return XmlConvert.ToString ((Decimal) o);
 699                         case TypeCode.Double:
 700                                 return XmlConvert.ToString ((Double) o);
 701                         case TypeCode.Int16:
 702                                 return XmlConvert.ToString ((Int16) o);
 703                         case TypeCode.Int32:
 704                                 return XmlConvert.ToString ((Int32) o);
 705                         case TypeCode.Int64:
 706                                 return XmlConvert.ToString ((Int64) o);
 707                         case TypeCode.SByte:
 708                                 return XmlConvert.ToString ((SByte) o);
 709                         case TypeCode.Single:
 710                                 return XmlConvert.ToString ((Single) o);
 711                         case TypeCode.UInt16:
 712                                 return XmlConvert.ToString ((UInt16) o);
 713                         case TypeCode.UInt32:
 714                                 return XmlConvert.ToString ((UInt32) o);
 715                         case TypeCode.UInt64:
 716                                 return XmlConvert.ToString ((UInt64) o);
 717                         }
 718                         if (o is TimeSpan) return XmlConvert.ToString ((TimeSpan) o);
 719                         if (o is Guid) return XmlConvert.ToString ((Guid) o);
 720                         return o.ToString();
 721                 }
 722
 723                 private void WriteTable( XmlWriter writer, DataTable table, XmlWriteMode mode )
 724                 {
 725                         DataRow[] rows = new DataRow [table.Rows.Count];
 726                         table.Rows.CopyTo (rows, 0);
 727                         WriteTable (writer, rows, mode);
 728                 }
 729
 730                 private void WriteTable( XmlWriter writer, DataRow[] rows, XmlWriteMode mode )
 731                 {
 732                         //The columns can be attributes, hidden, elements, or simple content
 733                         //There can be 0-1 simple content cols or 0-* elements
 734                         System.Collections.ArrayList atts;
 735                         System.Collections.ArrayList elements;
 736                         DataColumn simple = null;
 737
 738                         if (rows.Length == 0) return;
 739                         DataTable table = rows[0].Table;
 740                         SplitColumns( table, out atts, out elements, out simple );
 741
 742                         foreach( DataRow row in rows )
 743                         {
 744                                 //sort out the namespacing
 745                                 string nspc = table.Namespace.Length > 0 ? table.Namespace : Namespace;
 746
 747                                 // First check are all the rows null. If they are we just write empty element
 748                                 bool AllNulls = true;
 749                                 foreach (DataColumn dc in table.Columns) {
 750
 751                                         if (row [dc.ColumnName] != DBNull.Value) {
 752                                                 AllNulls = false;
 753                                                 break;
 754                                         }
 755                                 }
 756
 757                                 // If all of the columns were null, we have to write empty element
 758                                 if (AllNulls) {
 759                                         writer.WriteElementString (table.TableName, "");
 760                                         continue;
 761                                 }
 762
 763                                 WriteStartElement( writer, mode, nspc, table.Prefix, table.TableName );
 764
 765                                 foreach( DataColumn col in atts )
 766                                 {
 767                                         WriteAttributeString( writer, mode, col.Namespace, col.Prefix, col.ColumnName, row[col].ToString() );
 768                                 }
 769
 770                                 if( simple != null )
 771                                 {
 772                                         writer.WriteString( WriteObjectXml(row[simple]) );
 773                                 }
 774                                 else
 775                                 {
 776                                         foreach( DataColumn col in elements )
 777                                         {
 778                                                 string colnspc = nspc;
 779                                                 object rowObject = row [col];
 780
 781                                                 if (rowObject == null || rowObject == DBNull.Value)
 782                                                         continue;
 783
 784                                                 if( col.Namespace != null )
 785                                                 {
 786                                                         colnspc = col.Namespace;
 787                                                 }
 788
 789                                                 //TODO check if I can get away with write element string
 790                                                 WriteStartElement( writer, mode, colnspc, col.Prefix, col.ColumnName );
 791                                                 writer.WriteString( WriteObjectXml(rowObject) );
 792                                                 writer.WriteEndElement();
 793                                         }
 794                                 }
 795
 796                                 foreach (DataRelation relation in table.ChildRelations) {
 797                                         if (relation.Nested) {
 798                                                 WriteTable (writer, row.GetChildRows(relation), mode);
 799                                         }
 800                                 }
 801
 802                                 writer.WriteEndElement();
 803                         }
 804
 805                 }
 806
 807                 private void WriteStartElement( XmlWriter writer, XmlWriteMode mode, string nspc, string prefix, string name )
 808                 {
 809                         switch(  mode )
 810                                 {
 811                                         case XmlWriteMode.WriteSchema:
 812                                                 if( nspc == null || nspc == "" )
 813                                                 {
 814                                                         writer.WriteStartElement( name );
 815                                                 }
 816                                                 else if( prefix != null )
 817                                                 {
 818                                                         writer.WriteStartElement(prefix, name, nspc );
 819                                                 }
 820                                                 else
 821                                                 {
 822                                                         writer.WriteStartElement( writer.LookupPrefix( nspc ), name, nspc );
 823                                                 }
 824                                                 break;
 825                                         case XmlWriteMode.DiffGram:
 826                                                 throw new NotImplementedException();
 827                                         default:
 828                                                 writer.WriteStartElement(name );
 829                                                 break;
 830                                 };
 831                 }
 832
 833                 private void WriteAttributeString( XmlWriter writer, XmlWriteMode mode, string nspc, string prefix, string name, string stringValue )
 834                 {
 835                         switch(  mode )
 836                                 {
 837                                         case XmlWriteMode.WriteSchema:
 838                                                 writer.WriteAttributeString(prefix, name, nspc );
 839                                                 break;
 840                                         case XmlWriteMode.DiffGram:
 841                                                 throw new NotImplementedException();
 842                                         default:
 843                                                 writer.WriteAttributeString(name, stringValue );
 844                                                 break;
 845                                 };
 846                 }
 847
 848                 private void DoWriteXmlSchema( XmlWriter writer )
 849                 {
 850                         //Create the root element and declare all the namespaces etc
 851                         writer.WriteStartElement(XmlConstants.SchemaPrefix, XmlConstants.SchemaElement,
 852                                                                                 XmlConstants.SchemaNamespace );
 853                         writer.WriteAttributeString( XmlConstants.TargetNamespace, Namespace );
 854                         writer.WriteAttributeString( "xmlns:" + XmlConstants.TnsPrefix, Namespace );
 855                         writer.WriteAttributeString( "xmlns", Namespace );
 856                         writer.WriteAttributeString(  "xmlns:" + XmlConstants.MsdataPrefix,
 857                                                     XmlConstants.MsdataNamespace );
 858                         //Set up the attribute and element forms.
 859                         //TODO - is it possible to change this?
 860                         //I couldn't spot if it was so I assumed
 861                         //that this is set to qualified all round basedon the MS output
 862                         writer.WriteAttributeString( XmlConstants.AttributeFormDefault,
 863                                                     XmlConstants.Qualified );
 864                         writer.WriteAttributeString( XmlConstants.ElementFormDefault,
 865                                                     XmlConstants.Qualified );
 866
 867
 868                         //<xs:element name="DSName msdata:IsDataSet="true" msdata:Locale="machine-locale">
 869                         //Create the data set element
 870                         //All the tables are represented as choice elements in an unlimited series
 871                         writer.WriteStartElement( XmlConstants.SchemaPrefix,
 872                                                         XmlConstants.Element,
 873                                                         XmlConstants.SchemaNamespace );
 874
 875                         writer.WriteAttributeString( XmlConstants.Name, DataSetName );
 876                         writer.WriteAttributeString( XmlConstants.MsdataPrefix,  XmlConstants.IsDataSet, XmlConstants.MsdataNamespace, "true" );
 877                         //FIXME - sort out the locale string!
 878
 879                         writer.WriteAttributeString( XmlConstants.MsdataPrefix, XmlConstants.Locale, XmlConstants.MsdataNamespace, Thread.CurrentThread.CurrentCulture.Name);
 880
 881                         //<xs:complexType>
 882                         writer.WriteStartElement( XmlConstants.SchemaPrefix,
 883                                                         XmlConstants.ComplexType,
 884                                                         XmlConstants.SchemaNamespace );
 885
 886                         //<xs:choice maxOccurs="unbounded">
 887                         writer.WriteStartElement( XmlConstants.SchemaPrefix,
 888                                                         XmlConstants.Choice,
 889                                                         XmlConstants.SchemaNamespace );
 890
 891                         writer.WriteAttributeString( XmlConstants.MaxOccurs, XmlConstants.Unbounded );
 892
 893
 894                         //Write out schema for each table in order, providing it is not
 895                         //part of another table structure via a nested parent relationship
 896                         foreach( DataTable table in Tables )
 897                         {
 898                                 bool isTopLevel = true;
 899                                 foreach( DataRelation rel in table.ParentRelations )
 900                                 {
 901                                         if( rel.Nested )
 902                                         {
 903                                                 isTopLevel = false;
 904                                                 break;
 905                                         }
 906                                 }
 907
 908                                 if( isTopLevel )
 909                                 {
 910                                         WriteTableSchema(  writer, table );
 911                                 }
 912                         }
 913
 914                         //</xs:choice>
 915                         writer.WriteEndElement();
 916                         //</xs:complexType>
 917                         writer.WriteEndElement();
 918
 919                         //TODO - now add in the relationships as key and unique constraints etc
 920
 921                         //</xs:element>
 922                         writer.WriteEndElement();
 923
 924
 925                         //</schema>
 926                         writer.WriteEndElement();
 927                 }
 928
 929                 private void WriteTableSchema( XmlWriter writer, DataTable table )
 930                 {
 931                         ArrayList elements;
 932                         ArrayList atts;
 933                         DataColumn simple;
 934
 935                         SplitColumns( table,out  atts, out elements, out simple );
 936
 937                         //<xs:element name="TableName">
 938                         writer.WriteStartElement( XmlConstants.SchemaPrefix,
 939                                                  XmlConstants.Element,
 940                                                  XmlConstants.SchemaNamespace );
 941
 942                         writer.WriteAttributeString( XmlConstants.Name, table.TableName );
 943
 944                         //<xs:complexType>
 945                         writer.WriteStartElement( XmlConstants.SchemaPrefix,
 946                                                  XmlConstants.ComplexType,
 947                                                  XmlConstants.SchemaNamespace );
 948
 949                         //TODO - what about the simple content?
 950                         if( elements.Count == 0 )
 951                         {
 952                         }
 953                         else
 954                         {
 955                         //A sequence of element types or a simple content node
 956                         //<xs:sequence>
 957                         writer.WriteStartElement( XmlConstants.SchemaPrefix,
 958                                                  XmlConstants.Sequence,
 959                                                  XmlConstants.SchemaNamespace );
 960                         foreach( DataColumn col in elements )
 961                         {
 962                                 //<xs:element name=ColumnName type=MappedType Ordinal=index>
 963                                 writer.WriteStartElement( XmlConstants.SchemaPrefix,
 964                                                  XmlConstants.Element,
 965                                                  XmlConstants.SchemaNamespace );
 966
 967                                 writer.WriteAttributeString( XmlConstants.Name, col.ColumnName );
 968
 969                                 if (col.ColumnName != col.Caption && col.Caption != string.Empty)
 970                                         writer.WriteAttributeString( XmlConstants.MsdataPrefix, XmlConstants.Caption,
 971                                                                      XmlConstants.MsdataNamespace, col.Caption);
 972
 973                                 if (col.DefaultValue.ToString () != string.Empty)
 974                                         writer.WriteAttributeString( XmlConstants.Default, col.DefaultValue.ToString ());
 975
 976                                 writer.WriteAttributeString( XmlConstants.Type, MapType( col.DataType ) );
 977
 978                                 if( col.AllowDBNull )
 979                                 {
 980                                         writer.WriteAttributeString( XmlConstants.MinOccurs, "0" );
 981                                 }
 982
 983                                 //writer.WriteAttributeString( XmlConstants.MsdataPrefix,
 984                                 //                            XmlConstants.Ordinal,
 985                                 //                            XmlConstants.MsdataNamespace,
 986                                 //                            col.Ordinal.ToString() );
 987
 988                                 // Write SimpleType if column have MaxLength
 989                                 if (col.MaxLength > -1) {
 990
 991                                         WriteTableSimpleType (writer, col);
 992                                 }
 993
 994
 995                                 //</xs:element>
 996                                 writer.WriteEndElement();
 997                         }
 998                         //</xs:sequence>
 999                         writer.WriteEndElement();
1000
1001                         }
1002                         //Then a list of attributes
1003                         foreach( DataColumn col in atts )
1004                         {
1005                                 //<xs:attribute name=col.ColumnName form="unqualified" type=MappedType/>
1006                                 writer.WriteStartElement( XmlConstants.SchemaPrefix,
1007                                                  XmlConstants.Attribute,
1008                                                  XmlConstants.SchemaNamespace );
1009
1010                                 writer.WriteAttributeString( XmlConstants.Name, col.ColumnName );
1011                                 writer.WriteAttributeString( XmlConstants.Form, XmlConstants.Unqualified );
1012                                 writer.WriteAttributeString( XmlConstants.Type, MapType( col.DataType ) );
1013
1014                                 writer.WriteEndElement();
1015                         }
1016
1017                         //</xs:complexType>
1018                         writer.WriteEndElement();
1019
1020                         //</xs:element>
1021                         writer.WriteEndElement();
1022                 }
1023
1024                 private void WriteTableSimpleType (XmlWriter writer, DataColumn col)
1025                 {
1026                         // SimpleType
1027                         writer.WriteStartElement( XmlConstants.SchemaPrefix, XmlConstants.SimpleType,
1028                                                   XmlConstants.SchemaNamespace);
1029
1030                         // Restriction
1031                         writer.WriteStartElement( XmlConstants.SchemaPrefix, XmlConstants.Restriction,
1032                                                   XmlConstants.SchemaNamespace);
1033
1034                         writer.WriteAttributeString( XmlConstants.Base, MapType( col.DataType ) );
1035
1036                         // MaxValue
1037                         writer.WriteStartElement( XmlConstants.SchemaPrefix, XmlConstants.MaxLength,
1038                                                   XmlConstants.SchemaNamespace);
1039                         writer.WriteAttributeString( XmlConstants.Value, col.MaxLength.ToString ());
1040
1041
1042                         writer.WriteEndElement();
1043
1044                         writer.WriteEndElement();
1045
1046                         writer.WriteEndElement();
1047                 }
1048
1049                 ///<summary>
1050                 /// Helper function to split columns into attributes elements and simple
1051                 /// content
1052                 /// </summary>
1053                 private void SplitColumns(      DataTable table,
1054                                                                         out ArrayList atts,
1055                                                                         out ArrayList elements,
1056                                                                         out DataColumn simple)
1057                 {
1058                         //The columns can be attributes, hidden, elements, or simple content
1059                         //There can be 0-1 simple content cols or 0-* elements
1060                         atts = new System.Collections.ArrayList();
1061                         elements = new System.Collections.ArrayList();
1062                         simple = null;
1063
1064                         //Sort out the columns
1065                         foreach( DataColumn col in table.Columns )
1066                         {
1067                                 switch( col.ColumnMapping )
1068                                 {
1069                                         case MappingType.Attribute:
1070                                                 atts.Add( col );
1071                                                 break;
1072                                         case MappingType.Element:
1073                                                 elements.Add( col );
1074                                                 break;
1075                                         case MappingType.SimpleContent:
1076                                                 if( simple != null )
1077                                                 {
1078                                                         throw new System.InvalidOperationException( "There may only be one simple content element" );
1079                                                 }
1080                                                 simple = col;
1081                                                 break;
1082                                         default:
1083                                                 //ignore Hidden elements
1084                                                 break;
1085                                 }
1086                         }
1087                 }
1088
1089                 [MonoTODO]
1090                 private string MapType( Type type )
1091                 {
1092                         string Result = "xs:string";
1093
1094                         // TODO: More types to map?
1095
1096                         if (typeof (string) == type)
1097                                 Result = "xs:string";
1098                         else if (typeof (short) == type)
1099                                 Result = "xs:short";
1100                         else if (typeof (int) == type)
1101                                 Result = "xs:int";
1102                         else if (typeof (long) == type)
1103                                 Result = "xs:long";
1104                         else if (typeof (bool) == type)
1105                                 Result = "xs:boolean";
1106                         else if (typeof (byte) == type)
1107                                 Result = "xs:unsignedByte";
1108                         else if (typeof (char) == type)
1109                                 Result = "xs:char";
1110                         else if (typeof (DateTime) == type)
1111                                 Result = "xs:dateTime";
1112                         else if (typeof (decimal) == type)
1113                                 Result = "xs:decimal";
1114                         else if (typeof (double) == type)
1115                                 Result = "xs:double";
1116                         else if (typeof (sbyte) == type)
1117                                 Result = "xs:sbyte";
1118                         else if (typeof (Single) == type)
1119                                 Result = "xs:float";
1120                         else if (typeof (TimeSpan) == type)
1121                                 Result = "xs:duration";
1122                         else if (typeof (ushort) == type)
1123                                 Result = "xs:usignedShort";
1124                         else if (typeof (uint) == type)
1125                                 Result = "xs:unsignedInt";
1126                         else if (typeof (ulong) == type)
1127                                 Result = "xs:unsignedLong";
1128
1129                         return Result;
1130                 }
1131
1132                 #endregion //Private Xml Serialisation
1133         }
1134 }