source: oup/releases/0.17a/SQLiteTable3.pas@ 714

Last change on this file since 714 was 21, checked in by alloc, 18 years ago
File size: 22.8 KB
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[21]1unit SQLiteTable3;
2
3{
4 Simple classes for using SQLite's exec and get_table.
5
6 TSQLiteDatabase wraps the calls to open and close an SQLite database.
7 It also wraps SQLite_exec for queries that do not return a result set
8
9 TSQLiteTable wraps sqlite_get_table.
10 It allows accessing fields by name as well as index and can step through a
11 result set with the Next procedure.
12
13 Adapted by Tim Anderson (tim@itwriting.com)
14 Originally created by Pablo Pissanetzky (pablo@myhtpc.net)
15}
16
17interface
18
19uses
20 Windows, SQLite3, Classes, Sysutils;
21
22const
23 dtStr = 0;
24 dtInt = 1;
25 dtBool = 2;
26 dtNumeric = 3;
27 dtBlob = 4;
28
29type
30
31 ESQLiteException = class(Exception)
32 private
33 public
34 end;
35
36 TSQLiteTable = class;
37
38 TSQLiteDatabase = class
39 private
40 fDB: TSQLiteDB;
41 fInTrans: Boolean;
42 procedure RaiseError(s: string; SQL: string);
43
44 public
45 constructor Create(const FileName: string);
46 destructor Destroy; override;
47 function GetTable(const SQL: string): TSQLiteTable;
48 procedure ExecSQL(const SQL: string);
49 procedure UpdateBlob(const SQL: string; BlobData: TStream);
50 procedure BeginTransaction;
51 procedure Commit;
52 procedure Rollback;
53 function TableExists(TableName: string): boolean;
54 function GetLastInsertRowID: int64;
55
56 published
57 property isTransactionOpen: boolean read fInTrans;
58
59 end;
60
61 TSQLiteTable = class
62 private
63 fResults: TList;
64 fRowCount: Cardinal;
65 fColCount: Cardinal;
66 fCols: TStringList;
67 fColTypes: TList;
68 fRow: Cardinal;
69
70 function GetFields(I: Integer): string;
71 function GetEOF: Boolean;
72 function GetBOF: Boolean;
73 function GetColumns(I: Integer): string;
74 function GetFieldByName(FieldName: string): string;
75 function GetFieldIndex(FieldName: string): integer;
76 function GetCount: Integer;
77 function GetCountResult: Integer;
78
79
80 public
81 constructor Create(DB: TSQLiteDatabase; const SQL: string);
82 destructor Destroy; override;
83 function FieldAsInteger(FieldName: string): integer;
84 function FieldAsBool(FieldName: string): boolean;
85 function FieldAsBlob(FieldName: string): TMemoryStream;
86 function FieldAsBlobText(FieldName: string): string;
87 function FieldIsNull(FieldName: string): boolean;
88 function FieldAsString(FieldName: string): string;
89 function FieldAsDouble(FieldName: string): double;
90{ function FieldAsInteger(I: integer): integer;
91 function FieldAsBool(I: integer): boolean;
92 function FieldAsBlob(I: Integer): TMemoryStream;
93 function FieldAsBlobText(I: Integer): string;
94 function FieldIsNull(I: integer): boolean;
95 function FieldAsString(I: Integer): string;
96 function FieldAsDouble(I: Integer): double;
97} function Next: Boolean;
98 function Previous: Boolean;
99 property EOF: Boolean read GetEOF;
100 property BOF: Boolean read GetBOF;
101 property Fields[I: Integer]: string read GetFields;
102 property FieldByName[FieldName: string]: string read GetFieldByName;
103 property FieldIndex[FieldName: string]: integer read GetFieldIndex;
104 property Columns[I: Integer]: string read GetColumns;
105 property ColCount: Cardinal read fColCount;
106 property RowCount: Cardinal read fRowCount;
107 property Row: Cardinal read fRow;
108 function MoveFirst: boolean;
109 function MoveLast: boolean;
110
111
112 property Count: Integer read GetCount;
113
114 // The property CountResult is used when you execute count(*) queries.
115 // It returns 0 if the result set is empty or the value of the
116 // first field as an integer.
117 property CountResult: Integer read GetCountResult;
118 end;
119
120
121procedure DisposePointer(ptr: pointer); cdecl;
122
123implementation
124
125uses
126 strutils;
127
128
129procedure DisposePointer(ptr: pointer); cdecl;
130begin
131
132 if assigned(ptr) then
133 begin freemem(ptr) end;
134
135end;
136
137//------------------------------------------------------------------------------
138// TSQLiteDatabase
139//------------------------------------------------------------------------------
140
141constructor TSQLiteDatabase.Create(const FileName: string);
142var
143 Msg: pchar;
144 iResult: integer;
145begin
146 inherited Create;
147
148 self.fInTrans := false;
149
150 Msg := nil;
151 try
152 iResult := SQLite3_Open(PChar(FileName), Fdb);
153
154 if iResult <> SQLITE_OK then
155 begin
156 if Assigned(Fdb) then
157 begin
158 Msg := Sqlite3_ErrMsg(Fdb);
159 raise ESqliteException.CreateFmt('Failed to open database "%s" : %s', [FileName, Msg]);
160 end
161 else
162 begin raise ESqliteException.CreateFmt('Failed to open database "%s" : unknown error', [FileName]) end;
163 end;
164
165 //set a few configs
166 self.ExecSQL('PRAGMA SYNCHRONOUS=NORMAL;');
167
168 //this pragma not recommended and may disappear in future
169 //sqlite versions
170 //self.ExecSQL('PRAGMA full_column_names = 1;');
171
172 finally
173 if Assigned(Msg) then
174 begin SQLite3_Free(Msg) end;
175 end;
176
177
178end;
179
180
181//..............................................................................
182
183destructor TSQLiteDatabase.Destroy;
184begin
185
186 if self.fInTrans then
187 begin self.ExecSQL('ROLLBACK;') end; //assume rollback
188
189 if Assigned(fDB) then
190 begin SQLite3_Close(fDB) end;
191
192 inherited;
193end;
194
195function TSQLiteDatabase.GetLastInsertRowID: int64;
196begin
197 result := Sqlite3_LastInsertRowID(self.fDB);
198end;
199
200//..............................................................................
201
202procedure TSQLiteDatabase.RaiseError(s: string; SQL: string);
203//look up last error and raise and exception with an appropriate message
204var
205 Msg: PChar;
206begin
207
208 Msg := nil;
209
210 if sqlite3_errcode(self.fDB) <> SQLITE_OK then
211 Msg := sqlite3_errmsg(self.fDB);
212
213 if Msg <> nil then
214 raise ESqliteException.CreateFmt(s + ' "%s" : %s', [SQL, Msg])
215 else
216 raise ESqliteException.CreateFmt(s, [SQL, 'No message']);
217
218end;
219
220procedure TSQLiteDatabase.ExecSQL(const SQL: string);
221var
222 Stmt: TSQLiteStmt;
223 NextSQLStatement: Pchar;
224 iStepResult: integer;
225begin
226 try
227
228 if Sqlite3_Prepare(self.fDB, PChar(SQL), -1, Stmt, NextSQLStatement) <> SQLITE_OK then
229 begin RaiseError('Error executing SQL', SQL) end;
230
231 if (Stmt = nil) then
232 begin RaiseError('Could not prepare SQL statement', SQL) end;
233
234 iStepResult := Sqlite3_step(Stmt);
235
236 if (iStepResult <> SQLITE_DONE) then
237 begin RaiseError('Error executing SQL statement', SQL) end;
238
239 finally
240
241 if Assigned(Stmt) then
242 begin Sqlite3_Finalize(stmt) end;
243
244 end;
245end;
246
247procedure TSQLiteDatabase.UpdateBlob(const SQL: string; BlobData: TStream);
248var
249 iSize: integer;
250 ptr: pointer;
251 Stmt: TSQLiteStmt;
252 Msg: Pchar;
253 NextSQLStatement: Pchar;
254 iStepResult: integer;
255 iBindResult: integer;
256begin
257//expects SQL of the form 'UPDATE MYTABLE SET MYFIELD = ? WHERE MYKEY = 1'
258
259 if pos('?', SQL) = 0 then
260 begin RaiseError('SQL must include a ? parameter', SQL) end;
261
262 Msg := nil;
263 try
264
265 if Sqlite3_Prepare(self.fDB, PChar(SQL), -1, Stmt, NextSQLStatement) <> SQLITE_OK then
266 begin RaiseError('Could not prepare SQL statement', SQL) end;
267
268 if (Stmt = nil) then
269 begin RaiseError('Could not prepare SQL statement', SQL) end;
270
271//now bind the blob data
272 iSize := BlobData.size;
273
274 GetMem(ptr, iSize);
275
276 if (ptr = nil) then
277 begin raise ESqliteException.CreateFmt('Error getting memory to save blob', [SQL, 'Error']) end;
278
279 BlobData.position := 0;
280 BlobData.Read(ptr^, iSize);
281
282 iBindResult := SQLite3_BindBlob(stmt, 1, ptr, iSize, @DisposePointer);
283
284 if iBindResult <> SQLITE_OK then
285 begin RaiseError('Error binding blob to database', SQL) end;
286
287 iStepResult := Sqlite3_step(Stmt);
288
289 if (iStepResult <> SQLITE_DONE) then
290 begin RaiseError('Error executing SQL statement', SQL) end;
291
292 finally
293
294 if Assigned(Stmt) then
295 begin Sqlite3_Finalize(stmt) end;
296
297 if Assigned(Msg) then
298 begin SQLite3_Free(Msg) end;
299 end;
300
301end;
302
303//..............................................................................
304
305function TSQLiteDatabase.GetTable(const SQL: string): TSQLiteTable;
306begin
307 Result := TSQLiteTable.Create(Self, SQL);
308end;
309
310procedure TSQLiteDatabase.BeginTransaction;
311begin
312 if not self.fInTrans then
313 begin
314 self.ExecSQL('BEGIN TRANSACTION;');
315 self.fInTrans := true;
316 end
317 else
318 begin raise ESqliteException.Create('Transaction already open') end;
319end;
320
321procedure TSQLiteDatabase.Commit;
322begin
323 self.ExecSQL('COMMIT;');
324 self.fInTrans := false;
325end;
326
327procedure TSQLiteDatabase.Rollback;
328begin
329 self.ExecSQL('ROLLBACK;');
330 self.fInTrans := false;
331end;
332
333function TSQLiteDatabase.TableExists(TableName: string): boolean;
334var
335 sql: string;
336 ds: TSqliteTable;
337begin
338//returns true if table exists in the database
339 sql := 'select [sql] from sqlite_master where [type] = ''table'' and lower(name) = ''' + lowercase(TableName) + ''' ';
340
341 try
342
343 ds := self.GetTable(sql);
344
345 result := (ds.Count > 0);
346
347 finally
348
349 freeandnil(ds);
350
351 end;
352
353end;
354
355
356//------------------------------------------------------------------------------
357// TSQLiteTable
358//------------------------------------------------------------------------------
359
360constructor TSQLiteTable.Create(DB: TSQLiteDatabase; const SQL: string);
361var
362 Stmt: TSQLiteStmt;
363 NextSQLStatement: Pchar;
364 iStepResult: integer;
365
366 ptr: pointer;
367 iNumBytes: integer;
368 thisBlobValue: TMemoryStream;
369 thisStringValue: pstring;
370 thisBoolValue: pBoolean;
371 thisDoubleValue: pDouble;
372 thisIntValue: pInteger;
373 thisColType: pInteger;
374 i: integer;
375 DeclaredColType: Pchar;
376 ActualColType: integer;
377 ptrValue: Pchar;
378
379begin
380
381 try
382
383 self.fRowCount := 0;
384 self.fColCount := 0;
385
386//if there are several SQL statements in SQL, NextSQLStatment points to the
387//beginning of the next one. Prepare only prepares the first SQL statement.
388
389 if Sqlite3_Prepare(Db.fDB, PChar(SQL), -1, Stmt, NextSQLStatement) <> SQLITE_OK then
390 begin Db.RaiseError('Error executing SQL', SQL) end;
391
392 if (Stmt = nil) then
393 begin Db.RaiseError('Could not prepare SQL statement', SQL) end;
394
395 iStepResult := Sqlite3_step(Stmt);
396
397 while (iStepResult <> SQLITE_DONE) do
398 begin
399
400 case iStepResult of
401 SQLITE_ROW:
402 begin
403
404 inc(fRowCount);
405
406 if (fRowCount = 1) then
407 begin
408 //get data types
409 fCols := TStringList.Create;
410 fCols.CaseSensitive := False;
411 fColTypes := TList.Create;
412
413 fColCount := SQLite3_ColumnCount(stmt);
414
415 for i := 0 to Pred(fColCount) do
416 begin
417 fCols.Add(Sqlite3_ColumnName(stmt, i));
418 end;
419
420 for i := 0 to Pred(fColCount) do
421 begin
422
423 new(thisColType);
424 DeclaredColType := Sqlite3_ColumnDeclType(stmt, i);
425
426 if DeclaredColType = nil then begin
427 //use the actual column type instead
428 //seems to be needed for last_insert_rowid
429 thisColType^ := Sqlite3_ColumnType(stmt, i);
430 end else begin
431 DeclaredColType := strupper(DeclaredColType);
432
433 if DeclaredColType = 'INTEGER' then
434 begin thisColType^ := dtInt end
435 else
436 if DeclaredColType = 'BOOLEAN' then
437 begin thisColType^ := dtBool end
438 else
439 if (DeclaredColType = 'NUMERIC') or (DeclaredColType = 'FLOAT') or (DeclaredColType = 'DOUBLE') then
440 begin thisColType^ := dtNumeric end
441 else
442 if DeclaredColType = 'BLOB' then
443 begin thisColType^ := dtBlob end
444 else
445 begin thisColType^ := dtStr end;
446 end;
447
448 fColTypes.Add(thiscoltype);
449 end;
450
451 fResults := TList.Create;
452
453 end;
454
455 //get column values
456 for i := 0 to Pred(ColCount) do
457 begin
458
459 ActualColType := Sqlite3_ColumnType(stmt, i);
460 if (ActualColType = SQLITE_NULL) then
461 begin fResults.Add(nil) end
462 else
463 begin
464 if pInteger(fColTypes[i])^ = dtInt then
465 begin
466 new(thisintvalue);
467 thisintvalue^ := Sqlite3_ColumnInt(stmt, i);
468 fResults.Add(thisintvalue);
469 end
470 else
471 if pInteger(fColTypes[i])^ = dtBool then
472 begin
473 new(thisboolvalue);
474 thisboolvalue^ := not (Sqlite3_ColumnInt(stmt, i) = 0);
475 fResults.Add(thisboolvalue);
476 end
477 else
478 if pInteger(fColTypes[i])^ = dtNumeric then
479 begin
480 new(thisdoublevalue);
481 thisdoublevalue^ := Sqlite3_ColumnDouble(stmt, i);
482 fResults.Add(thisdoublevalue);
483 end
484 else
485 if pInteger(fColTypes[i])^ = dtBlob then
486 begin
487 iNumBytes := Sqlite3_ColumnBytes(stmt, i);
488
489 if iNumBytes = 0 then
490 begin thisblobvalue := nil end
491 else
492 begin
493 thisblobvalue := TMemoryStream.Create;
494 thisblobvalue.position := 0;
495 ptr := Sqlite3_ColumnBlob(stmt, i);
496 thisblobvalue.writebuffer(ptr^, iNumBytes);
497 end;
498 fResults.Add(thisblobvalue);
499
500 end
501 else
502 begin
503 new(thisstringvalue);
504 ptrValue := Sqlite3_ColumnText(stmt, i);
505 setstring(thisstringvalue^, ptrvalue, strlen(ptrvalue));
506 fResults.Add(thisstringvalue);
507 end;
508 end;
509
510 end;
511
512
513
514 end;
515
516 SQLITE_BUSY:
517 begin raise ESqliteException.CreateFmt('Could not prepare SQL statement', [SQL, 'SQLite is Busy']) end;
518 else
519 begin Db.RaiseError('Could not retrieve data', SQL) end;
520 end;
521
522 iStepResult := Sqlite3_step(Stmt);
523
524 end;
525
526 fRow := 0;
527
528 finally
529 if Assigned(Stmt) then
530 begin Sqlite3_Finalize(stmt) end;
531 end;
532
533end;
534
535//..............................................................................
536
537destructor TSQLiteTable.Destroy;
538var i: integer;
539 iColNo: integer;
540begin
541
542
543 if Assigned(fResults) then
544 begin for i := 0 to fResults.Count - 1 do
545 begin
546 //check for blob type
547 iColNo := (i mod fColCount);
548 case pInteger(self.fColTypes[iColNo])^ of
549 dtBlob:
550 begin
551 TMemoryStream(fResults[i]).free;
552 end;
553 dtStr:
554 begin
555 if fResults[i] <> nil then
556 begin
557 setstring(string(fResults[i]^), nil, 0);
558 dispose(fResults[i]);
559 end;
560 end;
561 else
562 begin
563 dispose(fResults[i])
564 end;
565 end;
566 end;
567 fResults.Free;
568 end;
569
570 if Assigned(fCols) then
571 begin fCols.Free end;
572
573 if Assigned(fColTypes) then
574 begin for i := 0 to fColTypes.Count - 1 do
575 begin
576 dispose(fColTypes[i]);
577 end end;
578 fColTypes.Free;
579 inherited;
580 end;
581
582//..............................................................................
583
584function TSQLiteTable.GetColumns(I: Integer): string;
585begin
586 Result := fCols[I];
587end;
588
589//..............................................................................
590
591function TSQLiteTable.GetCountResult: Integer;
592begin
593 if not EOF then
594 begin Result := StrToInt(Fields[0]) end
595 else
596 begin Result := 0 end;
597end;
598
599function TSQLiteTable.GetCount: Integer;
600begin
601 Result := FRowCount;
602end;
603
604//..............................................................................
605
606function TSQLiteTable.GetEOF: Boolean;
607begin
608 Result := fRow >= fRowCount;
609end;
610
611function TSQLiteTable.GetBOF: Boolean;
612begin
613 Result := fRow <= 0;
614end;
615
616//..............................................................................
617
618function TSQLiteTable.GetFieldByName(FieldName: string): string;
619begin
620 Result := GetFields(self.GetFieldIndex(FieldName));
621end;
622
623function TSQLiteTable.GetFieldIndex(FieldName: string): integer;
624begin
625
626 if (fCols = nil) then
627 begin
628 raise ESqliteException.Create('Field ' + fieldname + ' Not found. Empty dataset');
629 exit;
630 end;
631
632 if (fCols.count = 0) then
633 begin
634 raise ESqliteException.Create('Field ' + fieldname + ' Not found. Empty dataset');
635 exit;
636 end;
637
638 result := fCols.IndexOf(FieldName);
639
640 if (result < 0) then
641 begin raise ESqliteException.Create('Field not found in dataset: ' + fieldname) end;
642
643end;
644
645//..............................................................................
646
647function TSQLiteTable.GetFields(I: Integer): string;
648var
649 thisvalue: pstring;
650 ptr: pointer;
651 thisboolvalue: pBoolean;
652 thistype: integer;
653begin
654 Result := '';
655
656 if EOF then
657 begin raise ESqliteException.Create('Table is at End of File') end;
658
659//integer and boolean types are not stored in the resultset
660//as strings, so they should be retrieved using the type-specific
661//methods
662
663 thistype := pInteger(self.fColTypes[I])^;
664
665 if (thistype = dtInt) or (thistype = dtNumeric) or (thistype = dtBlob) then
666 begin
667 ptr := self.fResults[(self.frow * self.fColCount) + I];
668
669 if ptr <> nil then
670 begin
671 raise ESqliteException.Create('Use the specific methods for integer, numeric or blob fields');
672 end;
673
674 end
675 else
676 if pInteger(self.fColTypes[I])^ = dtBool then
677 begin
678 thisboolvalue := self.fResults[(self.frow * self.fColCount) + I];
679 if thisboolvalue <> nil then
680 begin if thisboolvalue^ then
681 begin result := '1' end
682 else
683 begin result := '0' end end;
684 end
685
686 else
687
688 begin
689
690 thisvalue := self.fResults[(self.frow * self.fColCount) + I];
691 if (thisvalue <> nil) then
692 begin Result := thisvalue^ end
693 else
694 begin Result := '' end; //return empty string
695 end;
696
697end;
698
699function TSqliteTable.FieldAsBlob(FieldName: string): TMemoryStream;
700var
701 i: Integer;
702begin
703
704 if EOF then
705 begin raise ESqliteException.Create('Table is at End of File') end;
706
707 i:=Self.FieldIndex[FieldName];
708
709 if (self.fResults[(self.frow * self.fColCount) + I] = nil) then
710 begin result := nil end
711 else
712 if pInteger(self.fColTypes[I])^ = dtBlob then
713 begin result := TMemoryStream(self.fResults[(self.frow * self.fColCount) + I]) end
714 else
715 begin raise ESqliteException.Create('Not a Blob field') end;
716end;
717
718function TSqliteTable.FieldAsBlobText(FieldName: string): string;
719var
720 MemStream: TMemoryStream;
721 Buffer: PChar;
722begin
723 result := '';
724
725 MemStream := self.FieldAsBlob(FieldName);
726
727 if MemStream <> nil then
728 begin if MemStream.Size > 0 then
729 begin
730 MemStream.position := 0;
731
732 Buffer := stralloc(MemStream.Size + 1);
733 MemStream.readbuffer(Buffer[0], MemStream.Size);
734 (Buffer + MemStream.Size)^ := chr(0);
735 SetString(Result, Buffer, MemStream.size);
736 strdispose(Buffer);
737 end end;
738
739end;
740
741
742function TSqliteTable.FieldAsInteger(FieldName: string): integer;
743var
744 i: Integer;
745begin
746
747 if EOF then
748 begin raise ESqliteException.Create('Table is at End of File') end;
749
750 i:=Self.FieldIndex[FieldName];
751
752 if (self.fResults[(self.frow * self.fColCount) + I] = nil) then
753 begin result := 0 end
754 else
755 if pInteger(self.fColTypes[I])^ = dtInt then
756 begin result := pInteger(self.fResults[(self.frow * self.fColCount) + I])^ end
757 else
758 if pInteger(self.fColTypes[I])^ = dtNumeric then
759 begin result := trunc(strtofloat(pString(self.fResults[(self.frow * self.fColCount) + I])^)) end
760 else
761 begin raise ESqliteException.Create('Not an integer or numeric field') end;
762
763end;
764
765function TSqliteTable.FieldAsDouble(FieldName: string): double;
766var
767 i: Integer;
768begin
769
770 if EOF then
771 begin raise ESqliteException.Create('Table is at End of File') end;
772
773 i:=Self.FieldIndex[FieldName];
774
775 if (self.fResults[(self.frow * self.fColCount) + I] = nil) then
776 begin result := 0 end
777 else
778 if pInteger(self.fColTypes[I])^ = dtInt then
779 begin result := pInteger(self.fResults[(self.frow * self.fColCount) + I])^ end
780 else
781 if pInteger(self.fColTypes[I])^ = dtNumeric then
782 begin result := pDouble(self.fResults[(self.frow * self.fColCount) + I])^ end
783 else
784 begin raise ESqliteException.Create('Not an integer or numeric field') end;
785
786end;
787
788function TSqliteTable.FieldAsBool(FieldName: string): boolean;
789var
790 i: Integer;
791begin
792
793 if EOF then
794 begin raise ESqliteException.Create('Table is at End of File') end;
795
796 i:=Self.FieldIndex[FieldName];
797
798 if (self.fResults[(self.frow * self.fColCount) + I] = nil) then
799 begin result := false end
800 else
801 if pInteger(self.fColTypes[I])^ = dtBool then
802 begin result := pBoolean(self.fResults[(self.frow * self.fColCount) + I])^ end
803 else
804 begin raise ESqliteException.Create('Not a boolean field') end;
805end;
806
807function TSqliteTable.FieldAsString(FieldName: string): string;
808var
809 i: Integer;
810begin
811
812 if EOF then
813 begin raise ESqliteException.Create('Table is at End of File') end;
814
815 i:=Self.FieldIndex[FieldName];
816
817 if (self.fResults[(self.frow * self.fColCount) + I] = nil) then
818 begin result := '' end
819 else
820 begin result := self.GetFields(I) end;
821
822end;
823
824function TSqliteTable.FieldIsNull(FieldName: string): boolean;
825var
826 thisvalue: pointer;
827 i: Integer;
828begin
829
830 if EOF then
831 begin raise ESqliteException.Create('Table is at End of File') end;
832
833 i:=Self.FieldIndex[FieldName];
834
835 thisvalue := self.fResults[(self.frow * self.fColCount) + I];
836 result := (thisvalue = nil);
837end;
838
839//..............................................................................
840
841function TSQLiteTable.Next: boolean;
842begin
843 result := false;
844 if not EOF then
845 begin
846 Inc(fRow);
847 result := true;
848 end;
849end;
850
851function TSQLiteTable.Previous: boolean;
852begin
853 result := false;
854 if not BOF then
855 begin
856 Dec(fRow);
857 result := true;
858 end;
859end;
860
861function TSQLiteTable.MoveFirst: boolean;
862begin
863 result := false;
864 if self.fRowCount > 0 then
865 begin
866 fRow := 0;
867 result := true;
868 end;
869end;
870
871function TSQLiteTable.MoveLast: boolean;
872begin
873 result := false;
874 if self.fRowCount > 0 then
875 begin
876 fRow := fRowCount - 1;
877 result := true;
878 end;
879end;
880
881
882end.
883
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