xref: /sqlite-3.40.0/src/test_bestindex.c (revision dfe4e6bb)
1 /*
2 ** 2016-03-01
3 **
4 ** The author disclaims copyright to this source code.  In place of
5 ** a legal notice, here is a blessing:
6 **
7 **    May you do good and not evil.
8 **    May you find forgiveness for yourself and forgive others.
9 **    May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** Code for testing the virtual table xBestIndex method and the query
13 ** planner.
14 */
15 
16 
17 /*
18 ** INSTRUCTIONS
19 **
20 ** This module exports a single tcl command - [register_tcl_module]. When
21 ** invoked, it registers a special virtual table module with a database
22 ** connection.
23 **
24 ** The virtual table is currently read-only. And always returns zero rows.
25 ** It is created with a single argument - the name of a Tcl command - as
26 ** follows:
27 **
28 **   CREATE VIRTUAL TABLE x1 USING tcl(tcl_command);
29 **
30 ** The command [tcl_command] is invoked when the table is first created (or
31 ** connected), when the xBestIndex() method is invoked and when the xFilter()
32 ** method is called. When it is created (or connected), it is invoked as
33 ** follows:
34 **
35 **   tcl_command xConnect
36 **
37 ** In this case the return value of the script is passed to the
38 ** sqlite3_declare_vtab() function to create the virtual table schema.
39 **
40 ** When the xBestIndex() method is called by SQLite, the Tcl command is
41 ** invoked as:
42 **
43 **   tcl_command xBestIndex CONSTRAINTS ORDERBY MASK
44 **
45 ** where CONSTRAINTS is a tcl representation of the aConstraints[] array,
46 ** ORDERBY is a representation of the contents of the aOrderBy[] array and
47 ** MASK is a copy of sqlite3_index_info.colUsed. For example if the virtual
48 ** table is declared as:
49 **
50 **   CREATE TABLE x1(a, b, c)
51 **
52 ** and the query is:
53 **
54 **   SELECT * FROM x1 WHERE a=? AND c<? ORDER BY b, c;
55 **
56 ** then the Tcl command is:
57 **
58 **   tcl_command xBestIndex                                  \
59 **     {{op eq column 0 usable 1} {op lt column 2 usable 1}} \
60 **     {{column 1 desc 0} {column 2 desc 0}}                 \
61 **     7
62 **
63 ** The return value of the script is a list of key-value pairs used to
64 ** populate the output fields of the sqlite3_index_info structure. Possible
65 ** keys and the usage of the accompanying values are:
66 **
67 **   "orderby"          (value of orderByConsumed flag)
68 **   "cost"             (value of estimatedCost field)
69 **   "rows"             (value of estimatedRows field)
70 **   "use"              (index of used constraint in aConstraint[])
71 **   "omit"             (like "use", but also sets omit flag)
72 **   "idxnum"           (value of idxNum field)
73 **   "idxstr"           (value of idxStr field)
74 **
75 ** Refer to code below for further details.
76 **
77 ** When SQLite calls the xFilter() method, this module invokes the following
78 ** Tcl script:
79 **
80 **   tcl_command xFilter IDXNUM IDXSTR ARGLIST
81 **
82 ** IDXNUM and IDXSTR are the values of the idxNum and idxStr parameters
83 ** passed to xFilter. ARGLIST is a Tcl list containing each of the arguments
84 ** passed to xFilter in text form.
85 **
86 ** As with xBestIndex(), the return value of the script is interpreted as a
87 ** list of key-value pairs. There is currently only one key defined - "sql".
88 ** The value must be the full text of an SQL statement that returns the data
89 ** for the current scan. The leftmost column returned by the SELECT is assumed
90 ** to contain the rowid. Other columns must follow, in order from left to
91 ** right.
92 */
93 
94 
95 #include "sqliteInt.h"
96 #if defined(INCLUDE_SQLITE_TCL_H)
97 #  include "sqlite_tcl.h"
98 #else
99 #  include "tcl.h"
100 #endif
101 
102 #ifndef SQLITE_OMIT_VIRTUALTABLE
103 
104 typedef struct tcl_vtab tcl_vtab;
105 typedef struct tcl_cursor tcl_cursor;
106 
107 /*
108 ** A fs virtual-table object
109 */
110 struct tcl_vtab {
111   sqlite3_vtab base;
112   Tcl_Interp *interp;
113   Tcl_Obj *pCmd;
114   sqlite3 *db;
115 };
116 
117 /* A tcl cursor object */
118 struct tcl_cursor {
119   sqlite3_vtab_cursor base;
120   sqlite3_stmt *pStmt;            /* Read data from here */
121 };
122 
123 /*
124 ** Dequote string z in place.
125 */
126 static void tclDequote(char *z){
127   char q = z[0];
128 
129   /* Set stack variable q to the close-quote character */
130   if( q=='[' || q=='\'' || q=='"' || q=='`' ){
131     int iIn = 1;
132     int iOut = 0;
133     if( q=='[' ) q = ']';
134 
135     while( ALWAYS(z[iIn]) ){
136       if( z[iIn]==q ){
137         if( z[iIn+1]!=q ){
138           /* Character iIn was the close quote. */
139           iIn++;
140           break;
141         }else{
142           /* Character iIn and iIn+1 form an escaped quote character. Skip
143           ** the input cursor past both and copy a single quote character
144           ** to the output buffer. */
145           iIn += 2;
146           z[iOut++] = q;
147         }
148       }else{
149         z[iOut++] = z[iIn++];
150       }
151     }
152 
153     z[iOut] = '\0';
154   }
155 }
156 
157 /*
158 ** This function is the implementation of both the xConnect and xCreate
159 ** methods of the fs virtual table.
160 **
161 ** The argv[] array contains the following:
162 **
163 **   argv[0]   -> module name  ("fs")
164 **   argv[1]   -> database name
165 **   argv[2]   -> table name
166 **   argv[...] -> other module argument fields.
167 */
168 static int tclConnect(
169   sqlite3 *db,
170   void *pAux,
171   int argc, const char *const*argv,
172   sqlite3_vtab **ppVtab,
173   char **pzErr
174 ){
175   Tcl_Interp *interp = (Tcl_Interp*)pAux;
176   tcl_vtab *pTab = 0;
177   char *zCmd = 0;
178   Tcl_Obj *pScript = 0;
179   int rc = SQLITE_OK;
180 
181   if( argc!=4 ){
182     *pzErr = sqlite3_mprintf("wrong number of arguments");
183     return SQLITE_ERROR;
184   }
185 
186   zCmd = sqlite3_malloc64(strlen(argv[3])+1);
187   pTab = (tcl_vtab*)sqlite3_malloc64(sizeof(tcl_vtab));
188   if( zCmd && pTab ){
189     memcpy(zCmd, argv[3], strlen(argv[3])+1);
190     tclDequote(zCmd);
191     memset(pTab, 0, sizeof(tcl_vtab));
192 
193     pTab->pCmd = Tcl_NewStringObj(zCmd, -1);
194     pTab->interp = interp;
195     pTab->db = db;
196     Tcl_IncrRefCount(pTab->pCmd);
197 
198     pScript = Tcl_DuplicateObj(pTab->pCmd);
199     Tcl_IncrRefCount(pScript);
200     Tcl_ListObjAppendElement(interp, pScript, Tcl_NewStringObj("xConnect", -1));
201 
202     rc = Tcl_EvalObjEx(interp, pScript, TCL_EVAL_GLOBAL);
203     if( rc!=TCL_OK ){
204       *pzErr = sqlite3_mprintf("%s", Tcl_GetStringResult(interp));
205       rc = SQLITE_ERROR;
206     }else{
207       rc = sqlite3_declare_vtab(db, Tcl_GetStringResult(interp));
208     }
209 
210     if( rc!=SQLITE_OK ){
211       sqlite3_free(pTab);
212       pTab = 0;
213     }
214   }else{
215     rc = SQLITE_NOMEM;
216   }
217 
218   sqlite3_free(zCmd);
219   *ppVtab = &pTab->base;
220   return rc;
221 }
222 
223 /* The xDisconnect and xDestroy methods are also the same */
224 static int tclDisconnect(sqlite3_vtab *pVtab){
225   tcl_vtab *pTab = (tcl_vtab*)pVtab;
226   Tcl_DecrRefCount(pTab->pCmd);
227   sqlite3_free(pTab);
228   return SQLITE_OK;
229 }
230 
231 /*
232 ** Open a new tcl cursor.
233 */
234 static int tclOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
235   tcl_cursor *pCur;
236   pCur = sqlite3_malloc(sizeof(tcl_cursor));
237   if( pCur==0 ) return SQLITE_NOMEM;
238   memset(pCur, 0, sizeof(tcl_cursor));
239   *ppCursor = &pCur->base;
240   return SQLITE_OK;
241 }
242 
243 /*
244 ** Close a tcl cursor.
245 */
246 static int tclClose(sqlite3_vtab_cursor *cur){
247   tcl_cursor *pCur = (tcl_cursor *)cur;
248   if( pCur ){
249     sqlite3_finalize(pCur->pStmt);
250     sqlite3_free(pCur);
251   }
252   return SQLITE_OK;
253 }
254 
255 static int tclNext(sqlite3_vtab_cursor *pVtabCursor){
256   tcl_cursor *pCsr = (tcl_cursor*)pVtabCursor;
257   if( pCsr->pStmt ){
258     tcl_vtab *pTab = (tcl_vtab*)(pVtabCursor->pVtab);
259     int rc = sqlite3_step(pCsr->pStmt);
260     if( rc!=SQLITE_ROW ){
261       const char *zErr;
262       rc = sqlite3_finalize(pCsr->pStmt);
263       pCsr->pStmt = 0;
264       if( rc!=SQLITE_OK ){
265         zErr = sqlite3_errmsg(pTab->db);
266         pTab->base.zErrMsg = sqlite3_mprintf("%s", zErr);
267       }
268     }
269   }
270   return SQLITE_OK;
271 }
272 
273 static int tclFilter(
274   sqlite3_vtab_cursor *pVtabCursor,
275   int idxNum, const char *idxStr,
276   int argc, sqlite3_value **argv
277 ){
278   tcl_cursor *pCsr = (tcl_cursor*)pVtabCursor;
279   tcl_vtab *pTab = (tcl_vtab*)(pVtabCursor->pVtab);
280   Tcl_Interp *interp = pTab->interp;
281   Tcl_Obj *pScript;
282   Tcl_Obj *pArg;
283   int ii;
284   int rc;
285 
286   pScript = Tcl_DuplicateObj(pTab->pCmd);
287   Tcl_IncrRefCount(pScript);
288   Tcl_ListObjAppendElement(interp, pScript, Tcl_NewStringObj("xFilter", -1));
289   Tcl_ListObjAppendElement(interp, pScript, Tcl_NewIntObj(idxNum));
290   if( idxStr ){
291     Tcl_ListObjAppendElement(interp, pScript, Tcl_NewStringObj(idxStr, -1));
292   }else{
293     Tcl_ListObjAppendElement(interp, pScript, Tcl_NewStringObj("", -1));
294   }
295 
296   pArg = Tcl_NewObj();
297   Tcl_IncrRefCount(pArg);
298   for(ii=0; ii<argc; ii++){
299     const char *zVal = (const char*)sqlite3_value_text(argv[ii]);
300     Tcl_Obj *pVal;
301     if( zVal==0 ){
302       pVal = Tcl_NewObj();
303     }else{
304       pVal = Tcl_NewStringObj(zVal, -1);
305     }
306     Tcl_ListObjAppendElement(interp, pArg, pVal);
307   }
308   Tcl_ListObjAppendElement(interp, pScript, pArg);
309   Tcl_DecrRefCount(pArg);
310 
311   rc = Tcl_EvalObjEx(interp, pScript, TCL_EVAL_GLOBAL);
312   if( rc!=TCL_OK ){
313     const char *zErr = Tcl_GetStringResult(interp);
314     rc = SQLITE_ERROR;
315     pTab->base.zErrMsg = sqlite3_mprintf("%s", zErr);
316   }else{
317     /* Analyze the scripts return value. The return value should be a tcl
318     ** list object with an even number of elements. The first element of each
319     ** pair must be one of:
320     **
321     **   "sql"          (SQL statement to return data)
322     */
323     Tcl_Obj *pRes = Tcl_GetObjResult(interp);
324     Tcl_Obj **apElem = 0;
325     int nElem;
326     rc = Tcl_ListObjGetElements(interp, pRes, &nElem, &apElem);
327     if( rc!=TCL_OK ){
328       const char *zErr = Tcl_GetStringResult(interp);
329       rc = SQLITE_ERROR;
330       pTab->base.zErrMsg = sqlite3_mprintf("%s", zErr);
331     }else{
332       for(ii=0; rc==SQLITE_OK && ii<nElem; ii+=2){
333         const char *zCmd = Tcl_GetString(apElem[ii]);
334         Tcl_Obj *p = apElem[ii+1];
335         if( sqlite3_stricmp("sql", zCmd)==0 ){
336           const char *zSql = Tcl_GetString(p);
337           rc = sqlite3_prepare_v2(pTab->db, zSql, -1, &pCsr->pStmt, 0);
338           if( rc!=SQLITE_OK ){
339             const char *zErr = sqlite3_errmsg(pTab->db);
340             pTab->base.zErrMsg = sqlite3_mprintf("unexpected: %s", zErr);
341           }
342         }else{
343           rc = SQLITE_ERROR;
344           pTab->base.zErrMsg = sqlite3_mprintf("unexpected: %s", zCmd);
345         }
346       }
347     }
348   }
349 
350   if( rc==SQLITE_OK ){
351     rc = tclNext(pVtabCursor);
352   }
353   return rc;
354 }
355 
356 static int tclColumn(
357   sqlite3_vtab_cursor *pVtabCursor,
358   sqlite3_context *ctx,
359   int i
360 ){
361   tcl_cursor *pCsr = (tcl_cursor*)pVtabCursor;
362   sqlite3_result_value(ctx, sqlite3_column_value(pCsr->pStmt, i+1));
363   return SQLITE_OK;
364 }
365 
366 static int tclRowid(sqlite3_vtab_cursor *pVtabCursor, sqlite_int64 *pRowid){
367   tcl_cursor *pCsr = (tcl_cursor*)pVtabCursor;
368   *pRowid = sqlite3_column_int64(pCsr->pStmt, 0);
369   return SQLITE_OK;
370 }
371 
372 static int tclEof(sqlite3_vtab_cursor *pVtabCursor){
373   tcl_cursor *pCsr = (tcl_cursor*)pVtabCursor;
374   return (pCsr->pStmt==0);
375 }
376 
377 static int tclBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
378   tcl_vtab *pTab = (tcl_vtab*)tab;
379   Tcl_Interp *interp = pTab->interp;
380   Tcl_Obj *pArg;
381   Tcl_Obj *pScript;
382   int ii;
383   int rc = SQLITE_OK;
384 
385   pScript = Tcl_DuplicateObj(pTab->pCmd);
386   Tcl_IncrRefCount(pScript);
387   Tcl_ListObjAppendElement(interp, pScript, Tcl_NewStringObj("xBestIndex", -1));
388 
389   pArg = Tcl_NewObj();
390   Tcl_IncrRefCount(pArg);
391   for(ii=0; ii<pIdxInfo->nConstraint; ii++){
392     struct sqlite3_index_constraint const *pCons = &pIdxInfo->aConstraint[ii];
393     Tcl_Obj *pElem = Tcl_NewObj();
394     const char *zOp = "?";
395 
396     Tcl_IncrRefCount(pElem);
397 
398     switch( pCons->op ){
399       case SQLITE_INDEX_CONSTRAINT_EQ:
400         zOp = "eq"; break;
401       case SQLITE_INDEX_CONSTRAINT_GT:
402         zOp = "gt"; break;
403       case SQLITE_INDEX_CONSTRAINT_LE:
404         zOp = "le"; break;
405       case SQLITE_INDEX_CONSTRAINT_LT:
406         zOp = "lt"; break;
407       case SQLITE_INDEX_CONSTRAINT_GE:
408         zOp = "ge"; break;
409       case SQLITE_INDEX_CONSTRAINT_MATCH:
410         zOp = "match"; break;
411       case SQLITE_INDEX_CONSTRAINT_LIKE:
412         zOp = "like"; break;
413       case SQLITE_INDEX_CONSTRAINT_GLOB:
414         zOp = "glob"; break;
415       case SQLITE_INDEX_CONSTRAINT_REGEXP:
416         zOp = "regexp"; break;
417     }
418 
419     Tcl_ListObjAppendElement(0, pElem, Tcl_NewStringObj("op", -1));
420     Tcl_ListObjAppendElement(0, pElem, Tcl_NewStringObj(zOp, -1));
421     Tcl_ListObjAppendElement(0, pElem, Tcl_NewStringObj("column", -1));
422     Tcl_ListObjAppendElement(0, pElem, Tcl_NewIntObj(pCons->iColumn));
423     Tcl_ListObjAppendElement(0, pElem, Tcl_NewStringObj("usable", -1));
424     Tcl_ListObjAppendElement(0, pElem, Tcl_NewIntObj(pCons->usable));
425 
426     Tcl_ListObjAppendElement(0, pArg, pElem);
427     Tcl_DecrRefCount(pElem);
428   }
429 
430   Tcl_ListObjAppendElement(0, pScript, pArg);
431   Tcl_DecrRefCount(pArg);
432 
433   pArg = Tcl_NewObj();
434   Tcl_IncrRefCount(pArg);
435   for(ii=0; ii<pIdxInfo->nOrderBy; ii++){
436     struct sqlite3_index_orderby const *pOrder = &pIdxInfo->aOrderBy[ii];
437     Tcl_Obj *pElem = Tcl_NewObj();
438     Tcl_IncrRefCount(pElem);
439 
440     Tcl_ListObjAppendElement(0, pElem, Tcl_NewStringObj("column", -1));
441     Tcl_ListObjAppendElement(0, pElem, Tcl_NewIntObj(pOrder->iColumn));
442     Tcl_ListObjAppendElement(0, pElem, Tcl_NewStringObj("desc", -1));
443     Tcl_ListObjAppendElement(0, pElem, Tcl_NewIntObj(pOrder->desc));
444 
445     Tcl_ListObjAppendElement(0, pArg, pElem);
446     Tcl_DecrRefCount(pElem);
447   }
448 
449   Tcl_ListObjAppendElement(0, pScript, pArg);
450   Tcl_DecrRefCount(pArg);
451 
452   Tcl_ListObjAppendElement(0, pScript, Tcl_NewWideIntObj(pIdxInfo->colUsed));
453 
454   rc = Tcl_EvalObjEx(interp, pScript, TCL_EVAL_GLOBAL);
455   Tcl_DecrRefCount(pScript);
456   if( rc!=TCL_OK ){
457     const char *zErr = Tcl_GetStringResult(interp);
458     rc = SQLITE_ERROR;
459     pTab->base.zErrMsg = sqlite3_mprintf("%s", zErr);
460   }else{
461     /* Analyze the scripts return value. The return value should be a tcl
462     ** list object with an even number of elements. The first element of each
463     ** pair must be one of:
464     **
465     **   "orderby"          (value of orderByConsumed flag)
466     **   "cost"             (value of estimatedCost field)
467     **   "rows"             (value of estimatedRows field)
468     **   "use"              (index of used constraint in aConstraint[])
469     **   "idxnum"           (value of idxNum field)
470     **   "idxstr"           (value of idxStr field)
471     **   "omit"             (index of omitted constraint in aConstraint[])
472     */
473     Tcl_Obj *pRes = Tcl_GetObjResult(interp);
474     Tcl_Obj **apElem = 0;
475     int nElem;
476     rc = Tcl_ListObjGetElements(interp, pRes, &nElem, &apElem);
477     if( rc!=TCL_OK ){
478       const char *zErr = Tcl_GetStringResult(interp);
479       rc = SQLITE_ERROR;
480       pTab->base.zErrMsg = sqlite3_mprintf("%s", zErr);
481     }else{
482       int iArgv = 1;
483       for(ii=0; rc==SQLITE_OK && ii<nElem; ii+=2){
484         const char *zCmd = Tcl_GetString(apElem[ii]);
485         Tcl_Obj *p = apElem[ii+1];
486         if( sqlite3_stricmp("cost", zCmd)==0 ){
487           rc = Tcl_GetDoubleFromObj(interp, p, &pIdxInfo->estimatedCost);
488         }else
489         if( sqlite3_stricmp("orderby", zCmd)==0 ){
490           rc = Tcl_GetIntFromObj(interp, p, &pIdxInfo->orderByConsumed);
491         }else
492         if( sqlite3_stricmp("idxnum", zCmd)==0 ){
493           rc = Tcl_GetIntFromObj(interp, p, &pIdxInfo->idxNum);
494         }else
495         if( sqlite3_stricmp("idxstr", zCmd)==0 ){
496           sqlite3_free(pIdxInfo->idxStr);
497           pIdxInfo->idxStr = sqlite3_mprintf("%s", Tcl_GetString(p));
498           pIdxInfo->needToFreeIdxStr = 1;
499         }else
500         if( sqlite3_stricmp("rows", zCmd)==0 ){
501           Tcl_WideInt x = 0;
502           rc = Tcl_GetWideIntFromObj(interp, p, &x);
503           pIdxInfo->estimatedRows = (tRowcnt)x;
504         }else
505         if( sqlite3_stricmp("use", zCmd)==0
506          || sqlite3_stricmp("omit", zCmd)==0
507         ){
508           int iCons;
509           rc = Tcl_GetIntFromObj(interp, p, &iCons);
510           if( rc==SQLITE_OK ){
511             if( iCons<0 || iCons>=pIdxInfo->nConstraint ){
512               rc = SQLITE_ERROR;
513               pTab->base.zErrMsg = sqlite3_mprintf("unexpected: %d", iCons);
514             }else{
515               int bOmit = (zCmd[0]=='o' || zCmd[0]=='O');
516               pIdxInfo->aConstraintUsage[iCons].argvIndex = iArgv++;
517               pIdxInfo->aConstraintUsage[iCons].omit = bOmit;
518             }
519           }
520         }else{
521           rc = SQLITE_ERROR;
522           pTab->base.zErrMsg = sqlite3_mprintf("unexpected: %s", zCmd);
523         }
524         if( rc!=SQLITE_OK && pTab->base.zErrMsg==0 ){
525           const char *zErr = Tcl_GetStringResult(interp);
526           pTab->base.zErrMsg = sqlite3_mprintf("%s", zErr);
527         }
528       }
529     }
530   }
531 
532   return rc;
533 }
534 
535 /*
536 ** A virtual table module that provides read-only access to a
537 ** Tcl global variable namespace.
538 */
539 static sqlite3_module tclModule = {
540   0,                         /* iVersion */
541   tclConnect,
542   tclConnect,
543   tclBestIndex,
544   tclDisconnect,
545   tclDisconnect,
546   tclOpen,                      /* xOpen - open a cursor */
547   tclClose,                     /* xClose - close a cursor */
548   tclFilter,                    /* xFilter - configure scan constraints */
549   tclNext,                      /* xNext - advance a cursor */
550   tclEof,                       /* xEof - check for end of scan */
551   tclColumn,                    /* xColumn - read data */
552   tclRowid,                     /* xRowid - read data */
553   0,                           /* xUpdate */
554   0,                           /* xBegin */
555   0,                           /* xSync */
556   0,                           /* xCommit */
557   0,                           /* xRollback */
558   0,                           /* xFindMethod */
559   0,                           /* xRename */
560 };
561 
562 /*
563 ** Decode a pointer to an sqlite3 object.
564 */
565 extern int getDbPointer(Tcl_Interp *interp, const char *zA, sqlite3 **ppDb);
566 
567 /*
568 ** Register the echo virtual table module.
569 */
570 static int SQLITE_TCLAPI register_tcl_module(
571   ClientData clientData, /* Pointer to sqlite3_enable_XXX function */
572   Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
573   int objc,              /* Number of arguments */
574   Tcl_Obj *CONST objv[]  /* Command arguments */
575 ){
576   sqlite3 *db;
577   if( objc!=2 ){
578     Tcl_WrongNumArgs(interp, 1, objv, "DB");
579     return TCL_ERROR;
580   }
581   if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;
582 #ifndef SQLITE_OMIT_VIRTUALTABLE
583   sqlite3_create_module(db, "tcl", &tclModule, (void *)interp);
584 #endif
585   return TCL_OK;
586 }
587 
588 #endif
589 
590 
591 /*
592 ** Register commands with the TCL interpreter.
593 */
594 int Sqlitetesttcl_Init(Tcl_Interp *interp){
595 #ifndef SQLITE_OMIT_VIRTUALTABLE
596   static struct {
597      char *zName;
598      Tcl_ObjCmdProc *xProc;
599      void *clientData;
600   } aObjCmd[] = {
601      { "register_tcl_module",   register_tcl_module, 0 },
602   };
603   int i;
604   for(i=0; i<sizeof(aObjCmd)/sizeof(aObjCmd[0]); i++){
605     Tcl_CreateObjCommand(interp, aObjCmd[i].zName,
606         aObjCmd[i].xProc, aObjCmd[i].clientData, 0);
607   }
608 #endif
609   return TCL_OK;
610 }
611