aboutsummaryrefslogblamecommitdiffstats
path: root/Medley/src/lib/SQLite/SQLiteTable3.pas
blob: 3aed54a4e7c5489453d32487321c5434ca0ee870 (plain) (tree)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500



























































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































                                                                                                                                                                                                                             
unit SQLiteTable3;

{
  Simple classes for using SQLite's exec and get_table.

  TSQLiteDatabase wraps the calls to open and close an SQLite database.
  It also wraps SQLite_exec for queries that do not return a result set

  TSQLiteTable wraps execution of SQL query.
  It run query and read all returned rows to internal buffer.
  It allows accessing fields by name as well as index and can move through a
  result set forward and backwards, or randomly to any row.

  TSQLiteUniTable wraps execution of SQL query.
  It run query as TSQLiteTable, but reading just first row only!
  You can step to next row (until not EOF) by 'Next' method.
  You cannot step backwards! (So, it is called as UniDirectional result set.)
  It not using any internal buffering, this class is very close to Sqlite API.
  It allows accessing fields by name as well as index on actual row only.
  Very good and fast for sequentional scanning of large result sets with minimal
    memory footprint.

  Warning! Do not close TSQLiteDatabase before any TSQLiteUniTable,
    because query is closed on TSQLiteUniTable destructor and database connection
    is used during TSQLiteUniTable live!

  SQL parameter usage:
    You can add named parameter values by call set of AddParam* methods.
    Parameters will be used for first next SQL statement only.
    Parameter name must be prefixed by ':', '$' or '@' and same prefix must be
    used in SQL statement!
    Sample:
      table.AddParamText(':str', 'some value');
      s := table.GetTableString('SELECT value FROM sometable WHERE id=:str');

   Notes from Andrew Retmanski on prepared queries
   The changes are as follows:

   SQLiteTable3.pas
   - Added new boolean property Synchronised (this controls the SYNCHRONOUS pragma as I found that turning this OFF increased the write performance in my application)
   - Added new type TSQLiteQuery (this is just a simple record wrapper around the SQL string and a TSQLiteStmt pointer)
   - Added PrepareSQL method to prepare SQL query - returns TSQLiteQuery
   - Added ReleaseSQL method to release previously prepared query
   - Added overloaded BindSQL methods for Integer and String types - these set new values for the prepared query parameters
   - Added overloaded ExecSQL method to execute a prepared TSQLiteQuery

   Usage of the new methods should be self explanatory but the process is in essence:

   1. Call PrepareSQL to return TSQLiteQuery 2. Call BindSQL for each parameter in the prepared query 3. Call ExecSQL to run the prepared query 4. Repeat steps 2 & 3 as required 5. Call ReleaseSQL to free SQLite resources

   One other point - the Synchronised property throws an error if used inside a transaction.

   Acknowledments
   Adapted by Tim Anderson (tim@itwriting.com)
   Originally created by Pablo Pissanetzky (pablo@myhtpc.net)
   Modified and enhanced by Lukas Gebauer
   Modified and enhanced by Tobias Gunkel
}

interface

{$IFDEF FPC}
  {$MODE Delphi}{$H+}
{$ENDIF}

uses
  {$IFDEF MSWINDOWS}
  Windows,
  {$ENDIF}
  SQLite3, Classes, SysUtils;

const

  dtInt = 1;
  dtNumeric = 2;
  dtStr = 3;
  dtBlob = 4;
  dtNull = 5;

type

  ESQLiteException = class(Exception)
  end;

  TSQliteParam = class
  public
    name: string;
    valuetype: integer;
    valueinteger: int64;
    valuefloat: double;
    valuedata: string;
  end;

  THookQuery = procedure(Sender: TObject; SQL: String) of object;

  TSQLiteQuery = record
    SQL: String;
    Statement: TSQLiteStmt;
  end;

  TSQLiteTable = class;
  TSQLiteUniTable = class;

  TSQLiteDatabase = class
  private
    fDB: TSQLiteDB;
    fInTrans: boolean;
    fSync: boolean;
    fParams: TList;
    FOnQuery: THookQuery;
    procedure RaiseError(s: string; SQL: string);
    procedure SetParams(Stmt: TSQLiteStmt);
    procedure BindData(Stmt: TSQLiteStmt; const Bindings: array of const);
    function GetRowsChanged: integer;
  protected
    procedure SetSynchronised(Value: boolean);
    procedure DoQuery(value: string); 
  public
    constructor Create(const FileName: string);
    destructor Destroy; override;
    function GetTable(const SQL: Ansistring): TSQLiteTable; overload;
    function GetTable(const SQL: Ansistring; const Bindings: array of const): TSQLiteTable; overload;
    procedure ExecSQL(const SQL: Ansistring); overload;
    procedure ExecSQL(const SQL: Ansistring; const Bindings: array of const); overload;
    procedure ExecSQL(Query: TSQLiteQuery); overload;
    function PrepareSQL(const SQL: Ansistring): TSQLiteQuery;
    procedure BindSQL(Query: TSQLiteQuery; const Index: Integer; const Value: Integer); overload;
    procedure BindSQL(Query: TSQLiteQuery; const Index: Integer; const Value: String); overload;
    procedure ReleaseSQL(Query: TSQLiteQuery);
    function GetUniTable(const SQL: Ansistring): TSQLiteUniTable; overload;
    function GetUniTable(const SQL: Ansistring; const Bindings: array of const): TSQLiteUniTable; overload;
    function GetTableValue(const SQL: Ansistring): int64; overload;
    function GetTableValue(const SQL: Ansistring; const Bindings: array of const): int64; overload;
    function GetTableString(const SQL: Ansistring): string; overload;
    function GetTableString(const SQL: Ansistring; const Bindings: array of const): string; overload;
    procedure GetTableStrings(const SQL: Ansistring; const Value: TStrings);
    procedure UpdateBlob(const SQL: Ansistring; BlobData: TStream);
    procedure BeginTransaction;
    procedure Commit;
    procedure Rollback;
    function TableExists(TableName: string): boolean;
    function ContainsColumn(Table: String; Column: String) : boolean;
    function GetLastInsertRowID: int64;
    function GetLastChangedRows: int64;
    procedure SetTimeout(Value: integer);
    function Version: string;
    procedure AddCustomCollate(name: string; xCompare: TCollateXCompare);
    //adds collate named SYSTEM for correct data sorting by user's locale
    Procedure AddSystemCollate;
    procedure ParamsClear;
    procedure AddParamInt(name: string; value: int64);
    procedure AddParamFloat(name: string; value: double);
    procedure AddParamText(name: string; value: string);
    procedure AddParamNull(name: string);
    property DB: TSQLiteDB read fDB;
  published
    property IsTransactionOpen: boolean read fInTrans;
    //database rows that were changed (or inserted or deleted) by the most recent SQL statement
    property RowsChanged : integer read getRowsChanged;
    property Synchronised: boolean read FSync write SetSynchronised;
    property OnQuery: THookQuery read FOnQuery write FOnQuery;
  end;

  TSQLiteTable = class
  private
    fResults: TList;
    fRowCount: cardinal;
    fColCount: cardinal;
    fCols: TStringList;
    fColTypes: TList;
    fRow: cardinal;
    function GetFields(I: cardinal): string;
    function GetEOF: boolean;
    function GetBOF: boolean;
    function GetColumns(I: integer): string;
    function GetFieldByName(FieldName: string): string;
    function GetFieldIndex(FieldName: string): integer;
    function GetCount: integer;
    function GetCountResult: integer;
  public
    constructor Create(DB: TSQLiteDatabase; const SQL: Ansistring); overload;
    constructor Create(DB: TSQLiteDatabase; const SQL: Ansistring; const Bindings: array of const); overload;
    destructor Destroy; override;
    function FieldAsInteger(I: cardinal): int64;
    function FieldAsBlob(I: cardinal): TMemoryStream;
    function FieldAsBlobText(I: cardinal): string;
    function FieldIsNull(I: cardinal): boolean;
    function FieldAsString(I: cardinal): string;
    function FieldAsDouble(I: cardinal): double;
    function Next: boolean;
    function Previous: boolean;
    property EOF: boolean read GetEOF;
    property BOF: boolean read GetBOF;
    property Fields[I: cardinal]: string read GetFields;
    property FieldByName[FieldName: string]: string read GetFieldByName;
    property FieldIndex[FieldName: string]: integer read GetFieldIndex;
    property Columns[I: integer]: string read GetColumns;
    property ColCount: cardinal read fColCount;
    property RowCount: cardinal read fRowCount;
    property Row: cardinal read fRow;
    function MoveFirst: boolean;
    function MoveLast: boolean;
    function MoveTo(position: cardinal): boolean;
    property Count: integer read GetCount;
    // The property CountResult is used when you execute count(*) queries.
    // It returns 0 if the result set is empty or the value of the
    // first field as an integer.
    property CountResult: integer read GetCountResult;
  end;

  TSQLiteUniTable = class
  private
    fColCount: cardinal;
    fCols: TStringList;
    fRow: cardinal;
    fEOF: boolean;
    fStmt: TSQLiteStmt;
    fDB: TSQLiteDatabase;
    fSQL: string;
    function GetFields(I: cardinal): string;
    function GetColumns(I: integer): string;
    function GetFieldByName(FieldName: string): string;
    function GetFieldIndex(FieldName: string): integer;
  public
    constructor Create(DB: TSQLiteDatabase; const SQL: Ansistring); overload;
    constructor Create(DB: TSQLiteDatabase; const SQL: Ansistring; const Bindings: array of const); overload;
    destructor Destroy; override;
    function FieldAsInteger(I: cardinal): int64;
    function FieldAsBlob(I: cardinal): TMemoryStream;
    function FieldAsBlobPtr(I: cardinal; out iNumBytes: integer): Pointer;
    function FieldAsBlobText(I: cardinal): string;
    function FieldIsNull(I: cardinal): boolean;
    function FieldAsString(I: cardinal): string;
    function FieldAsDouble(I: cardinal): double;
    function Next: boolean;
    property EOF: boolean read FEOF;
    property Fields[I: cardinal]: string read GetFields;
    property FieldByName[FieldName: string]: string read GetFieldByName;
    property FieldIndex[FieldName: string]: integer read GetFieldIndex;
    property Columns[I: integer]: string read GetColumns;
    property ColCount: cardinal read fColCount;
    property Row: cardinal read fRow;
  end;

procedure DisposePointer(ptr: pointer); cdecl;

{$IFDEF MSWINDOWS}
function SystemCollate(Userdta: pointer; Buf1Len: integer; Buf1: pointer;
    Buf2Len: integer; Buf2: pointer): integer; cdecl;
{$ENDIF}

implementation

procedure DisposePointer(ptr: pointer); cdecl;
begin
  if assigned(ptr) then
    freemem(ptr);
end;

{$IFDEF MSWINDOWS}
function SystemCollate(Userdta: pointer; Buf1Len: integer; Buf1: pointer;
    Buf2Len: integer; Buf2: pointer): integer; cdecl;
begin
  Result := CompareStringW(LOCALE_USER_DEFAULT, 0, PWideChar(Buf1), Buf1Len,
    PWideChar(Buf2), Buf2Len) - 2;
end;
{$ENDIF}

//------------------------------------------------------------------------------
// TSQLiteDatabase
//------------------------------------------------------------------------------

constructor TSQLiteDatabase.Create(const FileName: string);
var
  Msg: PAnsiChar;
  iResult: integer;
  utf8FileName: UTF8string;
begin
  inherited Create;
  fParams := TList.Create;

  self.fInTrans := False;

  Msg := nil;
  try
    utf8FileName := UTF8String(FileName);
    iResult := SQLite3_Open(PAnsiChar(utf8FileName), Fdb);

    if iResult <> SQLITE_OK then
      if Assigned(Fdb) then
      begin
        Msg := Sqlite3_ErrMsg(Fdb);
        raise ESqliteException.CreateFmt('Failed to open database "%s" : %s',
          [FileName, Msg]);
      end
      else
        raise ESqliteException.CreateFmt('Failed to open database "%s" : unknown error',
          [FileName]);

//set a few configs
//L.G. Do not call it here. Because busy handler is not setted here,
// any share violation causing exception!

//    self.ExecSQL('PRAGMA SYNCHRONOUS=NORMAL;');
//    self.ExecSQL('PRAGMA temp_store = MEMORY;');

  finally
    if Assigned(Msg) then
      SQLite3_Free(Msg);
  end;

end;

//..............................................................................

destructor TSQLiteDatabase.Destroy;
begin
  if self.fInTrans then
    self.Rollback;  //assume rollback
  if Assigned(fDB) then
    SQLite3_Close(fDB);
  ParamsClear;    
  fParams.Free;
  inherited;
end;

function TSQLiteDatabase.GetLastInsertRowID: int64;
begin
  Result := Sqlite3_LastInsertRowID(self.fDB);
end;

function TSQLiteDatabase.GetLastChangedRows: int64;
begin
  Result := SQLite3_TotalChanges(self.fDB);
end;

//..............................................................................

procedure TSQLiteDatabase.RaiseError(s: string; SQL: string);
//look up last error and raise an exception with an appropriate message
var
  Msg: PAnsiChar;
  ret : integer;
begin

  Msg := nil;

  ret := sqlite3_errcode(self.fDB);
  if ret <> SQLITE_OK then
    Msg := sqlite3_errmsg(self.fDB);

  if Msg <> nil then
    raise ESqliteException.CreateFmt(s +'.'#13'Error [%d]: %s.'#13'"%s": %s', [ret, SQLiteErrorStr(ret),SQL, Msg])
  else
    raise ESqliteException.CreateFmt(s, [SQL, 'No message']);

end;

procedure TSQLiteDatabase.SetSynchronised(Value: boolean);
begin
  if Value <> fSync then
  begin
    if Value then
      ExecSQL('PRAGMA synchronous = ON;')
    else
      ExecSQL('PRAGMA synchronous = OFF;');
    fSync := Value;
  end;
end;

procedure TSQLiteDatabase.BindData(Stmt: TSQLiteStmt; const Bindings: array of const);
var
  BlobMemStream: TCustomMemoryStream;
  BlobStdStream: TStream;
  DataPtr: Pointer;
  DataSize: integer;
  AnsiStr: AnsiString;
  AnsiStrPtr: PAnsiString;
  I: integer;
begin
  for I := 0 to High(Bindings) do
  begin
    case Bindings[I].VType of
      vtString,
      vtAnsiString, vtPChar,
      vtWideString, vtPWideChar,
      vtChar, vtWideChar:
      begin
        case Bindings[I].VType of
          vtString: begin // ShortString
            AnsiStr := Bindings[I].VString^;
            DataPtr := PAnsiChar(AnsiStr);
            DataSize := Length(AnsiStr)+1;
          end;
          vtPChar: begin
            DataPtr := Bindings[I].VPChar;
            DataSize := -1;
          end;
          vtAnsiString: begin
            AnsiStrPtr := PAnsiString(@Bindings[I].VAnsiString);
            DataPtr := PAnsiChar(AnsiStrPtr^);
            DataSize := Length(AnsiStrPtr^)+1;
          end;
          vtPWideChar: begin
            AnsiStr := UTF8Encode(WideString(Bindings[I].VPWideChar));
            DataPtr := PAnsiChar(AnsiStr);
            DataSize := -1;
          end;
          vtWideString: begin
            AnsiStr := UTF8Encode(PWideString(@Bindings[I].VWideString)^);
            DataPtr := PAnsiChar(AnsiStr);
            DataSize := -1;
          end;
          vtChar: begin
            AnsiStr := AnsiString(Bindings[I].VChar);
            DataPtr := PAnsiChar(AnsiStr);
            DataSize := 2;
          end;
          vtWideChar: begin
            AnsiStr := UTF8Encode(WideString(Bindings[I].VWideChar));
            DataPtr := PAnsiChar(AnsiStr);
            DataSize := -1;
          end;
          else
            raise ESqliteException.Create('Unknown string-type');
        end;
        if (sqlite3_bind_text(Stmt, I+1, DataPtr, DataSize, SQLITE_STATIC) <> SQLITE_OK) then
          RaiseError('Could not bind text', 'BindData');
      end;
      vtInteger:
        if (sqlite3_bind_int(Stmt, I+1, Bindings[I].VInteger) <> SQLITE_OK) then
          RaiseError('Could not bind integer', 'BindData');
      vtInt64:
        if (sqlite3_bind_int64(Stmt, I+1, Bindings[I].VInt64^) <> SQLITE_OK) then
          RaiseError('Could not bind int64', 'BindData');
      vtExtended:
        if (sqlite3_bind_double(Stmt, I+1, Bindings[I].VExtended^) <> SQLITE_OK) then
          RaiseError('Could not bind extended', 'BindData');
      vtBoolean:
        if (sqlite3_bind_int(Stmt, I+1, Integer(Bindings[I].VBoolean)) <> SQLITE_OK) then
          RaiseError('Could not bind boolean', 'BindData');
      vtPointer:
      begin
        if (Bindings[I].VPointer = nil) then
        begin
          if (sqlite3_bind_null(Stmt, I+1) <> SQLITE_OK) then
            RaiseError('Could not bind null', 'BindData');
        end
        else
          raise ESqliteException.Create('Unhandled pointer (<> nil)');
      end;
      vtObject:
      begin
        if (Bindings[I].VObject is TCustomMemoryStream) then
        begin
          BlobMemStream := TCustomMemoryStream(Bindings[I].VObject);
          if (sqlite3_bind_blob(Stmt, I+1, @PAnsiChar(BlobMemStream.Memory)[BlobMemStream.Position],
              BlobMemStream.Size-BlobMemStream.Position, SQLITE_STATIC) <> SQLITE_OK) then
          begin
            RaiseError('Could not bind BLOB', 'BindData');
          end;
        end
        else if (Bindings[I].VObject is TStream) then
        begin
          BlobStdStream := TStream(Bindings[I].VObject);
          DataSize := BlobStdStream.Size;

          GetMem(DataPtr, DataSize);
          if (DataPtr = nil) then
            raise ESqliteException.Create('Error getting memory to save blob');

          BlobStdStream.Position := 0;
          BlobStdStream.Read(DataPtr^, DataSize);

          if (sqlite3_bind_blob(stmt, I+1, DataPtr, DataSize, @DisposePointer) <> SQLITE_OK) then
            RaiseError('Could not bind BLOB', 'BindData');
        end
        else             
          raise ESqliteException.Create('Unhandled object-type in binding');
      end
      else 
      begin
        raise ESqliteException.Create('Unhandled binding');
      end;
    end;
  end;
end;

procedure TSQLiteDatabase.ExecSQL(const SQL: Ansistring);
begin
  ExecSQL(SQL, []);
end;

procedure TSQLiteDatabase.ExecSQL(const SQL: Ansistring; const Bindings: array of const);
var
  Stmt: TSQLiteStmt;
  NextSQLStatement: PAnsiChar;
  iStepResult: integer;
begin
  try
    if Sqlite3_Prepare_v2(self.fDB, PAnsiChar(SQL), -1, Stmt, NextSQLStatement) <>
      SQLITE_OK then
      RaiseError('Error executing SQL', SQL);
    if (Stmt = nil) then
      RaiseError('Could not prepare SQL statement', SQL);
    DoQuery(SQL);
    SetParams(Stmt);
    BindData(Stmt, Bindings);

    iStepResult := Sqlite3_step(Stmt);
    if (iStepResult <> SQLITE_DONE) then
      begin
      SQLite3_reset(stmt);
      RaiseError('Error executing SQL statement', SQL);
      end;
  finally
    if Assigned(Stmt) then
      Sqlite3_Finalize(stmt);
  end;
end;

procedure TSQLiteDatabase.ExecSQL(Query: TSQLiteQuery);
var
  iStepResult: integer;
begin
  if Assigned(Query.Statement) then
  begin
    iStepResult := Sqlite3_step(Query.Statement);

    if (iStepResult <> SQLITE_DONE) then
      begin
      SQLite3_reset(Query.Statement);
      RaiseError('Error executing prepared SQL statement', Query.SQL);
      end;
    Sqlite3_Reset(Query.Statement);
  end;
end;

function TSQLiteDatabase.PrepareSQL(const SQL: Ansistring): TSQLiteQuery;
var
  Stmt: TSQLiteStmt;
  NextSQLStatement: PAnsiChar;
begin
  Result.SQL := SQL;
  Result.Statement := nil;

  if Sqlite3_Prepare(self.fDB, PAnsiChar(SQL), -1, Stmt, NextSQLStatement) <>
    SQLITE_OK then
    RaiseError('Error executing SQL', SQL)
  else
    Result.Statement := Stmt;

  if (Result.Statement = nil) then
    RaiseError('Could not prepare SQL statement', SQL);
  DoQuery(SQL);
end;

procedure TSQLiteDatabase.BindSQL(Query: TSQLiteQuery; const Index: Integer; const Value: Integer);
begin
  if Assigned(Query.Statement) then
    sqlite3_Bind_Int(Query.Statement, Index, Value)
  else
    RaiseError('Could not bind integer to prepared SQL statement', Query.SQL);
end;

procedure TSQLiteDatabase.BindSQL(Query: TSQLiteQuery; const Index: Integer; const Value: String);
begin
  if Assigned(Query.Statement) then
    Sqlite3_Bind_Text(Query.Statement, Index, PAnsiChar(Value), Length(Value), Pointer(SQLITE_STATIC))
  else
    RaiseError('Could not bind string to prepared SQL statement', Query.SQL);
end;

procedure TSQLiteDatabase.ReleaseSQL(Query: TSQLiteQuery);
begin
  if Assigned(Query.Statement) then
  begin
    Sqlite3_Finalize(Query.Statement);
    Query.Statement := nil;
  end
  else
    RaiseError('Could not release prepared SQL statement', Query.SQL);
end;

procedure TSQLiteDatabase.UpdateBlob(const SQL: Ansistring; BlobData: TStream);
var
  iSize: integer;
  ptr: pointer;
  Stmt: TSQLiteStmt;
  Msg: PAnsiChar;
  NextSQLStatement: PAnsiChar;
  iStepResult: integer;
  iBindResult: integer;
begin
  //expects SQL of the form 'UPDATE MYTABLE SET MYFIELD = ? WHERE MYKEY = 1'
  if pos('?', SQL) = 0 then
    RaiseError('SQL must include a ? parameter', SQL);

  Msg := nil;
  try

    if Sqlite3_Prepare_v2(self.fDB, PAnsiChar(SQL), -1, Stmt, NextSQLStatement) <>
      SQLITE_OK then
      RaiseError('Could not prepare SQL statement', SQL);

    if (Stmt = nil) then
      RaiseError('Could not prepare SQL statement', SQL);
    DoQuery(SQL);

    //now bind the blob data
    iSize := BlobData.size;

    GetMem(ptr, iSize);

    if (ptr = nil) then
      raise ESqliteException.CreateFmt('Error getting memory to save blob',
        [SQL, 'Error']);

    BlobData.position := 0;
    BlobData.Read(ptr^, iSize);

    iBindResult := SQLite3_Bind_Blob(stmt, 1, ptr, iSize, @DisposePointer);

    if iBindResult <> SQLITE_OK then
      RaiseError('Error binding blob to database', SQL);

    iStepResult := Sqlite3_step(Stmt);

    if (iStepResult <> SQLITE_DONE) then
      begin
      SQLite3_reset(stmt);
      RaiseError('Error executing SQL statement', SQL);
      end;

  finally

    if Assigned(Stmt) then
      Sqlite3_Finalize(stmt);

    if Assigned(Msg) then
      SQLite3_Free(Msg);
  end;

end;

//..............................................................................

function TSQLiteDatabase.GetTable(const SQL: Ansistring): TSQLiteTable;
begin
  Result := TSQLiteTable.Create(Self, SQL);
end;

function TSQLiteDatabase.GetTable(const SQL: Ansistring; const Bindings: array of const): TSQLiteTable;
begin
  Result := TSQLiteTable.Create(Self, SQL, Bindings);
end;

function TSQLiteDatabase.GetUniTable(const SQL: Ansistring): TSQLiteUniTable;
begin
  Result := TSQLiteUniTable.Create(Self, SQL);
end;

function TSQLiteDatabase.GetUniTable(const SQL: Ansistring; const Bindings: array of const): TSQLiteUniTable;
begin
  Result := TSQLiteUniTable.Create(Self, SQL, Bindings);
end;

function TSQLiteDatabase.GetTableValue(const SQL: Ansistring): int64;
begin
  Result := GetTableValue(SQL, []);
end;

function TSQLiteDatabase.GetTableValue(const SQL: Ansistring; const Bindings: array of const): int64;
var
  Table: TSQLiteUniTable;
begin
  Result := 0;
  Table := self.GetUniTable(SQL, Bindings);
  try
    if not Table.EOF then
      Result := Table.FieldAsInteger(0);
  finally
    Table.Free;
  end;
end;

function TSQLiteDatabase.GetTableString(const SQL: Ansistring): String;
begin
  Result := GetTableString(SQL, []);
end;

function TSQLiteDatabase.GetTableString(const SQL: Ansistring; const Bindings: array of const): String;
var
  Table: TSQLiteUniTable;
begin
  Result := '';
  Table := self.GetUniTable(SQL, Bindings);
  try
    if not Table.EOF then
      Result := Table.FieldAsString(0);
  finally
    Table.Free;
  end;
end;

procedure TSQLiteDatabase.GetTableStrings(const SQL: Ansistring;
  const Value: TStrings);
var
  Table: TSQLiteUniTable;
begin
  Value.Clear;
  Table := self.GetUniTable(SQL);
  try
    while not table.EOF do
    begin
      Value.Add(Table.FieldAsString(0));
      table.Next;
    end;
  finally
    Table.Free;
  end;
end;

procedure TSQLiteDatabase.BeginTransaction;
begin
  if not self.fInTrans then
  begin
    self.ExecSQL('BEGIN TRANSACTION');
    self.fInTrans := True;
  end
  else
    raise ESqliteException.Create('Transaction already open');
end;

procedure TSQLiteDatabase.Commit;
begin
  self.ExecSQL('COMMIT');
  self.fInTrans := False;
end;

procedure TSQLiteDatabase.Rollback;
begin
  self.ExecSQL('ROLLBACK');
  self.fInTrans := False;
end;

function TSQLiteDatabase.TableExists(TableName: string): boolean;
var
  sql: string;
  ds: TSqliteTable;
begin
  //returns true if table exists in the database
  sql := 'select [sql] from sqlite_master where [type] = ''table'' and lower(name) = ''' +
    lowercase(TableName) + ''' ';
  ds := self.GetTable(sql);
  try
    Result := (ds.Count > 0);
  finally
    ds.Free;
  end;
end;

function TSQLiteDatabase.ContainsColumn(Table: String; Column: String) : boolean;
var
  sql: string;
  ds: TSqliteTable;
  i : integer;
begin
  sql := 'PRAGMA TABLE_INFO('+Table+');';
  ds := self.GetTable(sql);
  try
    Result := false;
    while (ds.Next() and not Result and not ds.EOF)  do
    begin
      if ds.FieldAsString(1) = Column then
        Result := true;
    end;
  finally
    ds.Free;
  end;
end;

procedure TSQLiteDatabase.SetTimeout(Value: integer);
begin
  SQLite3_BusyTimeout(self.fDB, Value);
end;

function TSQLiteDatabase.Version: string;
begin
  Result := SQLite3_Version;
end;

procedure TSQLiteDatabase.AddCustomCollate(name: string;
  xCompare: TCollateXCompare);
begin
  sqlite3_create_collation(fdb, PAnsiChar(name), SQLITE_UTF8, nil, xCompare);
end;

procedure TSQLiteDatabase.AddSystemCollate;
begin
  {$IFDEF MSWINDOWS}
  sqlite3_create_collation(fdb, 'SYSTEM', SQLITE_UTF16LE, nil, @SystemCollate);
  {$ENDIF}
end;

procedure TSQLiteDatabase.ParamsClear;
var
  n: integer;
begin
  for n := fParams.Count - 1 downto 0 do
    TSQliteParam(fparams[n]).free;
  fParams.Clear;
end;

procedure TSQLiteDatabase.AddParamInt(name: string; value: int64);
var
  par: TSQliteParam;
begin
  par := TSQliteParam.Create;
  par.name := name;
  par.valuetype := SQLITE_INTEGER;
  par.valueinteger := value;
  fParams.Add(par);
end;

procedure TSQLiteDatabase.AddParamFloat(name: string; value: double);
var
  par: TSQliteParam;
begin
  par := TSQliteParam.Create;
  par.name := name;
  par.valuetype := SQLITE_FLOAT;
  par.valuefloat := value;
  fParams.Add(par);
end;

procedure TSQLiteDatabase.AddParamText(name: string; value: string);
var
  par: TSQliteParam;
begin
  par := TSQliteParam.Create;
  par.name := name;
  par.valuetype := SQLITE_TEXT;
  par.valuedata := value;
  fParams.Add(par);
end;

procedure TSQLiteDatabase.AddParamNull(name: string);
var
  par: TSQliteParam;
begin
  par := TSQliteParam.Create;
  par.name := name;
  par.valuetype := SQLITE_NULL;
  fParams.Add(par);
end;

procedure TSQLiteDatabase.SetParams(Stmt: TSQLiteStmt);
var
  n: integer;
  i: integer;
  par: TSQliteParam;
begin
  try
    for n := 0 to fParams.Count - 1 do
    begin
      par := TSQliteParam(fParams[n]);
      i := sqlite3_bind_parameter_index(Stmt, PAnsiChar(par.name));
      if i > 0 then
      begin
        case par.valuetype of
          SQLITE_INTEGER:
            sqlite3_bind_int64(Stmt, i, par.valueinteger);
          SQLITE_FLOAT:
            sqlite3_bind_double(Stmt, i, par.valuefloat);
          SQLITE_TEXT:
            sqlite3_bind_text(Stmt, i, PAnsiChar(par.valuedata),
              length(par.valuedata), SQLITE_TRANSIENT);
          SQLITE_NULL:
            sqlite3_bind_null(Stmt, i);
        end;
      end;
    end;
  finally
    ParamsClear;
  end;
end;

//database rows that were changed (or inserted or deleted) by the most recent SQL statement
function TSQLiteDatabase.GetRowsChanged: integer;
begin
 Result := SQLite3_Changes(self.fDB);
end;

procedure TSQLiteDatabase.DoQuery(value: string);
begin
  if assigned(OnQuery) then
    OnQuery(Self, Value);
end;

//------------------------------------------------------------------------------
// TSQLiteTable
//------------------------------------------------------------------------------

constructor TSQLiteTable.Create(DB: TSQLiteDatabase; const SQL: Ansistring);
begin
  Create(DB, SQL, []);
end;

constructor TSQLiteTable.Create(DB: TSQLiteDatabase; const SQL: Ansistring; const Bindings: array of const);
var
  Stmt: TSQLiteStmt;
  NextSQLStatement: PAnsiChar;
  iStepResult: integer;
  ptr: pointer;
  iNumBytes: integer;
  thisBlobValue: TMemoryStream;
  thisStringValue: pstring;
  thisDoubleValue: pDouble;
  thisIntValue: pInt64;
  thisColType: pInteger;
  i: integer;
  DeclaredColType: PAnsiChar;
  ActualColType: integer;
  ptrValue: PAnsiChar;
begin
  inherited create;
  try
    self.fRowCount := 0;
    self.fColCount := 0;
    //if there are several SQL statements in SQL, NextSQLStatment points to the
    //beginning of the next one. Prepare only prepares the first SQL statement.
    if Sqlite3_Prepare_v2(DB.fDB, PAnsiChar(SQL), -1, Stmt, NextSQLStatement) <> SQLITE_OK then
      DB.RaiseError('Error executing SQL', SQL);
    if (Stmt = nil) then
      DB.RaiseError('Could not prepare SQL statement', SQL);
    DB.DoQuery(SQL);
    DB.SetParams(Stmt);
    DB.BindData(Stmt, Bindings);

    iStepResult := Sqlite3_step(Stmt);
    while (iStepResult <> SQLITE_DONE) do
    begin
      case iStepResult of
        SQLITE_ROW:
          begin
            Inc(fRowCount);
            if (fRowCount = 1) then
            begin
            //get data types
              fCols := TStringList.Create;
              fColTypes := TList.Create;
              fColCount := SQLite3_ColumnCount(stmt);
              for i := 0 to Pred(fColCount) do
                fCols.Add(AnsiUpperCase(Sqlite3_ColumnName(stmt, i)));
              for i := 0 to Pred(fColCount) do
              begin
                new(thisColType);
                DeclaredColType := Sqlite3_ColumnDeclType(stmt, i);
                if DeclaredColType = nil then
                  thisColType^ := Sqlite3_ColumnType(stmt, i) //use the actual column type instead
                //seems to be needed for last_insert_rowid
                else
                  if (DeclaredColType = 'INTEGER') or (DeclaredColType = 'BOOLEAN') then
                    thisColType^ := dtInt
                  else
                    if (DeclaredColType = 'NUMERIC') or
                      (DeclaredColType = 'FLOAT') or
                      (DeclaredColType = 'DOUBLE') or
                      (DeclaredColType = 'REAL') then
                      thisColType^ := dtNumeric
                    else
                      if DeclaredColType = 'BLOB' then
                        thisColType^ := dtBlob
                      else
                        thisColType^ := dtStr;
                fColTypes.Add(thiscoltype);
              end;
              fResults := TList.Create;
            end;

          //get column values
            for i := 0 to Pred(ColCount) do
            begin
              ActualColType := Sqlite3_ColumnType(stmt, i);
              if (ActualColType = SQLITE_NULL) then
                fResults.Add(nil)
              else
                if pInteger(fColTypes[i])^ = dtInt then
                begin
                  new(thisintvalue);
                  thisintvalue^ := Sqlite3_ColumnInt64(stmt, i);
                  fResults.Add(thisintvalue);
                end
                else
                  if pInteger(fColTypes[i])^ = dtNumeric then
                  begin
                    new(thisdoublevalue);
                    thisdoublevalue^ := Sqlite3_ColumnDouble(stmt, i);
                    fResults.Add(thisdoublevalue);
                  end
                  else
                    if pInteger(fColTypes[i])^ = dtBlob then
                    begin
                      iNumBytes := Sqlite3_ColumnBytes(stmt, i);
                      if iNumBytes = 0 then
                        thisblobvalue := nil
                      else
                      begin
                        thisblobvalue := TMemoryStream.Create;
                        thisblobvalue.position := 0;
                        ptr := Sqlite3_ColumnBlob(stmt, i);
                        thisblobvalue.writebuffer(ptr^, iNumBytes);
                      end;
                      fResults.Add(thisblobvalue);
                    end
                    else
                    begin
                      new(thisstringvalue);
                      ptrValue := Sqlite3_ColumnText(stmt, i);
                      setstring(thisstringvalue^, ptrvalue, strlen(ptrvalue));
                      fResults.Add(thisstringvalue);
                    end;
            end;
          end;
        SQLITE_BUSY:
          raise ESqliteException.CreateFmt('Could not prepare SQL statement',
            [SQL, 'SQLite is Busy']);
      else
        begin
        SQLite3_reset(stmt);
        DB.RaiseError('Could not retrieve data', SQL);
        end;
      end;
      iStepResult := Sqlite3_step(Stmt);
    end;
    fRow := 0;
  finally
    if Assigned(Stmt) then
      Sqlite3_Finalize(stmt);
  end;
end;

//..............................................................................

destructor TSQLiteTable.Destroy;
var
  i: cardinal;
  iColNo: integer;
begin
  if Assigned(fResults) then
  begin
    for i := 0 to fResults.Count - 1 do
    begin
      //check for blob type
      iColNo := (i mod fColCount);
      case pInteger(self.fColTypes[iColNo])^ of
        dtBlob:
          TMemoryStream(fResults[i]).Free;
        dtStr:
          if fResults[i] <> nil then
          begin
            setstring(string(fResults[i]^), nil, 0);
            dispose(fResults[i]);
          end;
      else
        dispose(fResults[i]);
      end;
    end;
    fResults.Free;
  end;
  if Assigned(fCols) then
    fCols.Free;
  if Assigned(fColTypes) then
    for i := 0 to fColTypes.Count - 1 do
      dispose(fColTypes[i]);
  fColTypes.Free;
  inherited;
end;

//..............................................................................

function TSQLiteTable.GetColumns(I: integer): string;
begin
  Result := fCols[I];
end;

//..............................................................................

function TSQLiteTable.GetCountResult: integer;
begin
  if not EOF then
    Result := StrToInt(Fields[0])
  else
    Result := 0;
end;

function TSQLiteTable.GetCount: integer;
begin
  Result := FRowCount;
end;

//..............................................................................

function TSQLiteTable.GetEOF: boolean;
begin
  Result := fRow >= fRowCount;
end;

function TSQLiteTable.GetBOF: boolean;
begin
  Result := fRow <= 0;
end;

//..............................................................................

function TSQLiteTable.GetFieldByName(FieldName: string): string;
begin
  Result := GetFields(self.GetFieldIndex(FieldName));
end;

function TSQLiteTable.GetFieldIndex(FieldName: string): integer;
begin
  if (fCols = nil) then
  begin
    raise ESqliteException.Create('Field ' + fieldname + ' Not found. Empty dataset');
    exit;
  end;

  if (fCols.count = 0) then
  begin
    raise ESqliteException.Create('Field ' + fieldname + ' Not found. Empty dataset');
    exit;
  end;

  Result := fCols.IndexOf(AnsiUpperCase(FieldName));

  if (result < 0) then
  begin
    raise ESqliteException.Create('Field not found in dataset: ' + fieldname)
  end;
end;

//..............................................................................

function TSQLiteTable.GetFields(I: cardinal): string;
var
  thisvalue: pstring;
  thistype: integer;
begin
  Result := '';
  if EOF then
    raise ESqliteException.Create('Table is at End of File');
  //integer types are not stored in the resultset
  //as strings, so they should be retrieved using the type-specific
  //methods
  thistype := pInteger(self.fColTypes[I])^;

  case thistype of
    dtStr:
      begin
        thisvalue := self.fResults[(self.frow * self.fColCount) + I];
        if (thisvalue <> nil) then
          Result := thisvalue^
        else
          Result := '';
      end;
    dtInt:
      Result := IntToStr(self.FieldAsInteger(I));
    dtNumeric:
      Result := FloatToStr(self.FieldAsDouble(I));
    dtBlob:
      Result := self.FieldAsBlobText(I);
  else
    Result := '';
  end;
end;

function TSqliteTable.FieldAsBlob(I: cardinal): TMemoryStream;
begin
  if EOF then
    raise ESqliteException.Create('Table is at End of File');
  if (self.fResults[(self.frow * self.fColCount) + I] = nil) then
    Result := nil
  else
    if pInteger(self.fColTypes[I])^ = dtBlob then
      Result := TMemoryStream(self.fResults[(self.frow * self.fColCount) + I])
    else
      raise ESqliteException.Create('Not a Blob field');
end;

function TSqliteTable.FieldAsBlobText(I: cardinal): string;
var
  MemStream: TMemoryStream;
  Buffer: PAnsiChar;
begin
  Result := '';
  MemStream := self.FieldAsBlob(I);
  if MemStream <> nil then
    if MemStream.Size > 0 then
      begin
        MemStream.position := 0;
        {$IFDEF UNICODE}
        Buffer := AnsiStralloc(MemStream.Size + 1);
        {$ELSE}
        Buffer := Stralloc(MemStream.Size + 1);
        {$ENDIF}
        MemStream.readbuffer(Buffer[0], MemStream.Size);
        (Buffer + MemStream.Size)^ := chr(0);
        SetString(Result, Buffer, MemStream.size);
        strdispose(Buffer);
      end;
     //do not free the TMemoryStream here; it is freed when
     //TSqliteTable is destroyed

end;


function TSqliteTable.FieldAsInteger(I: cardinal): int64;
begin
  if EOF then
    raise ESqliteException.Create('Table is at End of File');
  if (self.fResults[(self.frow * self.fColCount) + I] = nil) then
    Result := 0
  else
    if pInteger(self.fColTypes[I])^ = dtInt then
      Result := pInt64(self.fResults[(self.frow * self.fColCount) + I])^
    else
      if pInteger(self.fColTypes[I])^ = dtNumeric then
        Result := trunc(strtofloat(pString(self.fResults[(self.frow * self.fColCount) + I])^))
      else
        raise ESqliteException.Create('Not an integer or numeric field');
end;

function TSqliteTable.FieldAsDouble(I: cardinal): double;
begin
  if EOF then
    raise ESqliteException.Create('Table is at End of File');
  if (self.fResults[(self.frow * self.fColCount) + I] = nil) then
    Result := 0
  else
    if pInteger(self.fColTypes[I])^ = dtInt then
      Result := pInt64(self.fResults[(self.frow * self.fColCount) + I])^
    else
      if pInteger(self.fColTypes[I])^ = dtNumeric then
        Result := pDouble(self.fResults[(self.frow * self.fColCount) + I])^
      else
        raise ESqliteException.Create('Not an integer or numeric field');
end;

function TSqliteTable.FieldAsString(I: cardinal): string;
begin
  if EOF then
    raise ESqliteException.Create('Table is at End of File');
  if (self.fResults[(self.frow * self.fColCount) + I] = nil) then
    Result := ''
  else
    Result := self.GetFields(I);
end;

function TSqliteTable.FieldIsNull(I: cardinal): boolean;
var
  thisvalue: pointer;
begin
  if EOF then
    raise ESqliteException.Create('Table is at End of File');
  thisvalue := self.fResults[(self.frow * self.fColCount) + I];
  Result := (thisvalue = nil);
end;

//..............................................................................

function TSQLiteTable.Next: boolean;
begin
  Result := False;
  if not EOF then
  begin
    Inc(fRow);
    Result := True;
  end;
end;

function TSQLiteTable.Previous: boolean;
begin
  Result := False;
  if not BOF then
  begin
    Dec(fRow);
    Result := True;
  end;
end;

function TSQLiteTable.MoveFirst: boolean;
begin
  Result := False;
  if self.fRowCount > 0 then
  begin
    fRow := 0;
    Result := True;
  end;
end;

function TSQLiteTable.MoveLast: boolean;
begin
  Result := False;
  if self.fRowCount > 0 then
  begin
    fRow := fRowCount - 1;
    Result := True;
  end;
end;

function TSQLiteTable.MoveTo(position: cardinal): boolean;
begin
  Result := False;
  if (self.fRowCount > 0) and (self.fRowCount > position) then
  begin
    fRow := position;
    Result := True;
  end;
end;



{ TSQLiteUniTable }

constructor TSQLiteUniTable.Create(DB: TSQLiteDatabase; const SQL: Ansistring);
begin
  Create(DB, SQL, []);
end;

constructor TSQLiteUniTable.Create(DB: TSQLiteDatabase; const SQL: Ansistring; const Bindings: array of const);
var
  NextSQLStatement: PAnsiChar;
  i: integer;
begin
  inherited create;
  self.fDB := db;
  self.fEOF := false;
  self.fRow := 0;
  self.fColCount := 0;
  self.fSQL := SQL;
  if Sqlite3_Prepare_v2(DB.fDB, PAnsiChar(SQL), -1, fStmt, NextSQLStatement) <> SQLITE_OK then
    DB.RaiseError('Error executing SQL', SQL);
  if (fStmt = nil) then
    DB.RaiseError('Could not prepare SQL statement', SQL);
  DB.DoQuery(SQL);
  DB.SetParams(fStmt);
  DB.BindData(fStmt, Bindings);

  //get data types
  fCols := TStringList.Create;
  fColCount := SQLite3_ColumnCount(fstmt);
  for i := 0 to Pred(fColCount) do
    fCols.Add(AnsiUpperCase(Sqlite3_ColumnName(fstmt, i)));

  Next;
end;

destructor TSQLiteUniTable.Destroy;
begin
  if Assigned(fStmt) then
    Sqlite3_Finalize(fstmt);
  if Assigned(fCols) then
    fCols.Free;
  inherited;
end;

function TSQLiteUniTable.FieldAsBlob(I: cardinal): TMemoryStream;
var
  iNumBytes: integer;
  ptr: pointer;
begin
  Result := TMemoryStream.Create;
  iNumBytes := Sqlite3_ColumnBytes(fstmt, i);
  if iNumBytes > 0 then
  begin
    ptr := Sqlite3_ColumnBlob(fstmt, i);
    Result.writebuffer(ptr^, iNumBytes);
    Result.Position := 0;
  end;
end;

function TSQLiteUniTable.FieldAsBlobPtr(I: cardinal; out iNumBytes: integer): Pointer;
begin
  iNumBytes := Sqlite3_ColumnBytes(fstmt, i);
  Result := Sqlite3_ColumnBlob(fstmt, i);
end;

function TSQLiteUniTable.FieldAsBlobText(I: cardinal): string;
var
  MemStream: TMemoryStream;
  Buffer: PAnsiChar;
begin
  Result := '';
  MemStream := self.FieldAsBlob(I);
  if MemStream <> nil then
    try
      if MemStream.Size > 0 then
      begin
        MemStream.position := 0;
        {$IFDEF UNICODE}
        Buffer := AnsiStralloc(MemStream.Size + 1);
        {$ELSE}
        Buffer := Stralloc(MemStream.Size + 1);
        {$ENDIF}
        MemStream.readbuffer(Buffer[0], MemStream.Size);
        (Buffer + MemStream.Size)^ := chr(0);
        SetString(Result, Buffer, MemStream.size);
        strdispose(Buffer);
      end;
    finally
      MemStream.Free;
    end;
end;

function TSQLiteUniTable.FieldAsDouble(I: cardinal): double;
begin
  Result := Sqlite3_ColumnDouble(fstmt, i);
end;

function TSQLiteUniTable.FieldAsInteger(I: cardinal): int64;
begin
  Result := Sqlite3_ColumnInt64(fstmt, i);
end;

function TSQLiteUniTable.FieldAsString(I: cardinal): string;
begin
  Result := self.GetFields(I);
end;

function TSQLiteUniTable.FieldIsNull(I: cardinal): boolean;
begin
  Result := Sqlite3_ColumnText(fstmt, i) = nil;
end;

function TSQLiteUniTable.GetColumns(I: integer): string;
begin
  Result := fCols[I];
end;

function TSQLiteUniTable.GetFieldByName(FieldName: string): string;
begin
  Result := GetFields(self.GetFieldIndex(FieldName));
end;

function TSQLiteUniTable.GetFieldIndex(FieldName: string): integer;
begin
  if (fCols = nil) then
  begin
    raise ESqliteException.Create('Field ' + fieldname + ' Not found. Empty dataset');
    exit;
  end;

  if (fCols.count = 0) then
  begin
    raise ESqliteException.Create('Field ' + fieldname + ' Not found. Empty dataset');
    exit;
  end;

  Result := fCols.IndexOf(AnsiUpperCase(FieldName));

  if (result < 0) then
  begin
    raise ESqliteException.Create('Field not found in dataset: ' + fieldname)
  end;
end;

function TSQLiteUniTable.GetFields(I: cardinal): string;
begin
  Result := Sqlite3_ColumnText(fstmt, i);
end;

function TSQLiteUniTable.Next: boolean;
var
  iStepResult: integer;
begin
  fEOF := true;
  iStepResult := Sqlite3_step(fStmt);
  case iStepResult of
    SQLITE_ROW:
      begin
        fEOF := false;
        inc(fRow);
      end;
    SQLITE_DONE:
      // we are on the end of dataset
      // return EOF=true only
      ;
  else
    begin
    SQLite3_reset(fStmt);
    fDB.RaiseError('Could not retrieve data', fSQL);
    end;
  end;
  Result := not fEOF;
end;

end.