Remove the NullCallback opcode. Handle the empty_result_set pragma inside

the sqlite_exec() function. (CVS 1244)

FossilOrigin-Name: f72134852bf33d13fd2bc6f35251e4b33bc10fac

diff --git a/manifest b/manifest
index 185188b907ccc1f17c93eca602890c7ed01b1aa4..c41424b5be19504eebf786bf41bdf1238e017ab4 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Eliminate\sobsolete\scode\sassociated\swith\sthe\solder\scallback\sfunctionality.\s(CVS\s1243)
-D 2004-02-14T23:59:57
+C Remove\sthe\sNullCallback\sopcode.\s\sHandle\sthe\sempty_result_set\spragma\sinside\nthe\ssqlite_exec()\sfunction.\s(CVS\s1244)
+D 2004-02-16T03:44:02
 F Makefile.in cfd75c46b335881999333a9e4b982fa8491f200b
 F Makefile.linux-gcc b86a99c493a5bfb402d1d9178dcdc4bd4b32f906
 F README f1de682fbbd94899d50aca13d387d1b3fd3be2dd
@@ -27,26 +27,26 @@ F src/btree.c 0a40efb01fa3a431a16d8604f603431d8c9cebfa
 F src/btree.h 41cb3ff6ebc3f6da2d0a074e39ff8c7a2287469f
 F src/btree_rb.c 32b2cb4285c0fbd53b89de021637b63d52257e54
 F src/build.c e6d71a3babd1f523abdd806555be3430adbd69eb
-F src/copy.c 9e47975ea96751c658bcf1a0c4f0bb7c6ee61e73
+F src/copy.c 391ce142f6b1faa093867ecee134f61a5028a9af
 F src/date.c c9d2bfd40b1c95f8f97d53a5eba981d7167c7b61
-F src/delete.c 0778fe05df0a1d62ac27fd1a3dba237c186ff4d1
+F src/delete.c b8e3fc122f4e103130d764085c3fd7b697b301c4
 F src/encode.c 9e70ea1e4e746f23f18180949e94f1bb1c2220d3
 F src/expr.c fdd57e18cf6f2dea42e1e1930930b32ec6351c47
 F src/func.c cbc5edd10c82a5193b9ca0726873328be445e6c1
 F src/hash.c 9b56ef3b291e25168f630d5643a4264ec011c70e
 F src/hash.h 3247573ab95b9dd90bcca0307a75d9a16da1ccc7
-F src/insert.c 01f66866f35c986eab4a57373ca689a3255ef2df
-F src/main.c bb7cd00ac7551b542c8e54296ecec19d9732ef4e
+F src/insert.c f0a95cb6e6b0aacc916c76a89649196e4f10adca
+F src/main.c 992114429fa45f0015cab0648caeeb9d9a12294a
 F src/md5.c fe4f9c9c6f71dfc26af8da63e4d04489b1430565
 F src/os.c f5fc4954725b2fcd852979f2746085fe8ca27710
 F src/os.h 250a3789be609adfee5c5aa20137ce8683276f24
 F src/pager.c 29ddad4dd454f0aaa98e2bcd327710ab9f02f833
 F src/pager.h 82332878799280145639a48d88cdb4058925e3f6
 F src/parse.y 226bbdba2dee362d4b1cacc424bd82f7740071ee
-F src/pragma.c 89d62c31c6f0a43376fe8d20549b87a6d30c467a
+F src/pragma.c 23dac1d20cc278e1fbbae5181eba0508ca7f2d7a
 F src/printf.c 84e4ea4ba49cbbf930e95e82295127ad5843ae1f
 F src/random.c 775913e0b7fbd6295d21f12a7bd35b46387c44b2
-F src/select.c 330166e328d7c8c737547b9d9a5bbe00431f9aed
+F src/select.c 3b8eaf1a9585cbcf7a90bc9915b9b2f75ffe3921
 F src/shell.c c3d3404fa82bb0808444fda9884d1bb572fd18b9
 F src/sqlite.h.in 64f016cd5ce190643a0f47760188fdf4e0b2227e
 F src/sqliteInt.h 2b5e327ba20a864a95ff12e0d243dabfbc37d613
@@ -58,10 +58,10 @@ F src/test3.c 30985ebdfaf3ee1462a9b0652d3efbdc8d9798f5
 F src/test4.c dcbbbb382626fd466a7c46907f74db35fc8bad64
 F src/tokenize.c 6676b946fd8825b67ab52140af4fdc57a70bda48
 F src/trigger.c c647a442427fb8c1cd761eb03b1710c9d5675a8b
-F src/update.c 24260b4fda00c9726d27699a0561d53c0dccc397
+F src/update.c 10459f44c9eb46c70b1c63e79cc35f3256f09986
 F src/util.c 64995b5949a5d377629ffd2598747bc771cade1e
 F src/vacuum.c d9e80c2b36ee1f623dbf1bdf3cedad24a23f87ac
-F src/vdbe.c 90debe895f49342179f9670ee84da4c0a48cec19
+F src/vdbe.c e1825bcb40da6dd8429b24f404dc31265face31e
 F src/vdbe.h b9f6f1b5f9d1bfceb8bda5e396877ba584c4519c
 F src/vdbeInt.h af83bd700b1cc10b9cad2af146002927e0d421c9
 F src/vdbeaux.c 11f1fa94869870ebd8338ada489e64647414268b
@@ -184,7 +184,7 @@ F www/sqlite.tcl 3c83b08cf9f18aa2d69453ff441a36c40e431604
 F www/tclsqlite.tcl b9271d44dcf147a93c98f8ecf28c927307abd6da
 F www/vdbe.tcl 9b9095d4495f37697fd1935d10e14c6015e80aa1
 F www/whentouse.tcl a8335bce47cc2fddb07f19052cb0cb4d9129a8e4
-P af5c2be4aed1c50f69eb9634cf051a26263dcf51
-R 95d34ebfa714eff82ca160ac5c46d401
+P 2dbc4593ca5c1cf75039c8b4471b1e47faa849f0
+R 4f2635b8f97864f9158485f11af66f00
 U drh
-Z 7d29870d7ab5460e1dbcbf55076eba4b
+Z 5bfa6a509eb1a2b3c9004d75dfbc7acf

diff --git a/manifest.uuid b/manifest.uuid
index dafa02d0745f25c1e10667e382e8a7ef1ee09b24..5b40890543b30556aee95bc798c9dcd7fb04d6b1 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-2dbc4593ca5c1cf75039c8b4471b1e47faa849f0
\ No newline at end of file
+f72134852bf33d13fd2bc6f35251e4b33bc10fac
\ No newline at end of file

diff --git a/src/copy.c b/src/copy.c
index 1ee38eccb289f100f19b1fd5656926a1831cc202..579a786f4a3f85d16458204670b2abe02aa09e35 100644 (file)
--- a/src/copy.c
+++ b/src/copy.c
@@ -11,7 +11,7 @@
 *************************************************************************
 ** This file contains code used to implement the COPY command.
 **
-** $Id: copy.c,v 1.6 2003/06/02 22:50:26 drh Exp $
+** $Id: copy.c,v 1.7 2004/02/16 03:44:02 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -107,7 +107,7 @@ void sqliteCopy(
     sqliteVdbeAddOp(v, OP_Noop, 0, 0);
     sqliteEndWriteOperation(pParse);
     if( db->flags & SQLITE_CountRows ){
-      sqliteVdbeAddOp(v, OP_ColumnName, 0, 0);
+      sqliteVdbeAddOp(v, OP_ColumnName, 0, 1);
       sqliteVdbeChangeP3(v, -1, "rows inserted", P3_STATIC);
       sqliteVdbeAddOp(v, OP_Callback, 1, 0);
     }

diff --git a/src/delete.c b/src/delete.c
index fcc5f5bf1bcbeb6cb5d7e41e22f38d2060ee7a6d..0b49b7cda5343cee6c0c732f80fede0a5316c249 100644 (file)
--- a/src/delete.c
+++ b/src/delete.c
@@ -12,7 +12,7 @@
 ** This file contains C code routines that are called by the parser
 ** to handle DELETE FROM statements.
 **
-** $Id: delete.c,v 1.58 2004/01/19 04:54:29 jplyon Exp $
+** $Id: delete.c,v 1.59 2004/02/16 03:44:02 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -305,7 +305,7 @@ void sqliteDeleteFrom(
   ** Return the number of rows that were deleted.
   */
   if( db->flags & SQLITE_CountRows ){
-    sqliteVdbeAddOp(v, OP_ColumnName, 0, 0);
+    sqliteVdbeAddOp(v, OP_ColumnName, 0, 1);
     sqliteVdbeChangeP3(v, -1, "rows deleted", P3_STATIC);
     sqliteVdbeAddOp(v, OP_Callback, 1, 0);
   }

diff --git a/src/insert.c b/src/insert.c
index cdbf66514bb4fb5b26495b2fef8d5e0560c8458d..ba02810fd1ac9ec402eeba09ea62befa4012a349 100644 (file)
--- a/src/insert.c
+++ b/src/insert.c
@@ -12,7 +12,7 @@
 ** This file contains C code routines that are called by the parser
 ** to handle INSERT statements in SQLite.
 **
-** $Id: insert.c,v 1.90 2003/12/06 21:43:56 drh Exp $
+** $Id: insert.c,v 1.91 2004/02/16 03:44:02 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -541,7 +541,7 @@ void sqliteInsert(
   ** Return the number of rows inserted.
   */
   if( db->flags & SQLITE_CountRows ){
-    sqliteVdbeAddOp(v, OP_ColumnName, 0, 0);
+    sqliteVdbeAddOp(v, OP_ColumnName, 0, 1);
     sqliteVdbeChangeP3(v, -1, "rows inserted", P3_STATIC);
     sqliteVdbeAddOp(v, OP_MemLoad, iCntMem, 0);
     sqliteVdbeAddOp(v, OP_Callback, 1, 0);

diff --git a/src/main.c b/src/main.c
index 7f1386108fdc82713bd53b52f570591234a534ad..fb6a8e145dc2bc35a8beac233601e52302c36af3 100644 (file)
--- a/src/main.c
+++ b/src/main.c
@@ -14,7 +14,7 @@
 ** other files are for internal use by SQLite and should not be
 ** accessed by users of the library.
 **
-** $Id: main.c,v 1.155 2004/02/14 23:59:57 drh Exp $
+** $Id: main.c,v 1.156 2004/02/16 03:44:02 drh Exp $
 */
 #include "sqliteInt.h"
 #include "os.h"
@@ -614,6 +614,7 @@ int sqlite_exec(
   sqlite_vm *pVm;
   int nRetry = 0;
   int nChange = 0;
+  int nCallback;
 
   if( zSql==0 ) return SQLITE_OK;
   while( rc==SQLITE_OK && zSql[0] ){
@@ -628,16 +629,22 @@ int sqlite_exec(
       break;
     }
     db->nChange += nChange;
+    nCallback = 0;
     while(1){
       int nArg;
       char **azArg, **azCol;
       rc = sqlite_step(pVm, &nArg, (const char***)&azArg,(const char***)&azCol);
       if( rc==SQLITE_ROW ){
-        if( xCallback(pArg, nArg, azArg, azCol) ){
+        if( xCallback!=0 && xCallback(pArg, nArg, azArg, azCol) ){
           sqlite_finalize(pVm, 0);
           return SQLITE_ABORT;
         }
+        nCallback++;
       }else{
+        if( rc==SQLITE_DONE && nCallback==0
+          && (db->flags & SQLITE_NullCallback)!=0 && xCallback!=0 ){
+          xCallback(pArg, nArg, azArg, azCol);
+        }
         rc = sqlite_finalize(pVm, pzErrMsg);
         if( rc==SQLITE_SCHEMA && nRetry<2 ){
           nRetry++;

diff --git a/src/pragma.c b/src/pragma.c
index 4456c633b3cf05b156e0ad6fb2c5e6f8f287ef77..337f601166fd6eed3142553a534dbf20b0ee195f 100644 (file)
--- a/src/pragma.c
+++ b/src/pragma.c
@@ -11,7 +11,7 @@
 *************************************************************************
 ** This file contains code used to implement the PRAGMA command.
 **
-** $Id: pragma.c,v 1.13 2004/01/19 04:52:29 jplyon Exp $
+** $Id: pragma.c,v 1.14 2004/02/16 03:44:02 drh Exp $
 */
 #include "sqliteInt.h"
 #include <ctype.h>
@@ -140,7 +140,7 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
       { OP_Integer,     0, 0,        0},
       { OP_Ne,          0, 6,        0},
       { OP_Integer,     MAX_PAGES,0, 0},
-      { OP_ColumnName,  0, 0,        "cache_size"},
+      { OP_ColumnName,  0, 1,        "cache_size"},
       { OP_Callback,    1, 0,        0},
     };
     if( pRight->z==pLeft->z ){
@@ -178,7 +178,7 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
   */
   if( sqliteStrICmp(zLeft,"cache_size")==0 ){
     static VdbeOp getCacheSize[] = {
-      { OP_ColumnName,  0, 0,        "cache_size"},
+      { OP_ColumnName,  0, 1,        "cache_size"},
       { OP_Callback,    1, 0,        0},
     };
     if( pRight->z==pLeft->z ){
@@ -216,7 +216,7 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
   */
   if( sqliteStrICmp(zLeft,"default_synchronous")==0 ){
     static VdbeOp getSync[] = {
-      { OP_ColumnName,  0, 0,        "synchronous"},
+      { OP_ColumnName,  0, 1,        "synchronous"},
       { OP_ReadCookie,  0, 3,        0},
       { OP_Dup,         0, 0,        0},
       { OP_If,          0, 0,        0},  /* 3 */
@@ -269,7 +269,7 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
   */
   if( sqliteStrICmp(zLeft,"synchronous")==0 ){
     static VdbeOp getSync[] = {
-      { OP_ColumnName,  0, 0,        "synchronous"},
+      { OP_ColumnName,  0, 1,        "synchronous"},
       { OP_Callback,    1, 0,        0},
     };
     if( pRight->z==pLeft->z ){
@@ -344,7 +344,7 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
         { OP_ColumnName,  2, 0,       "type"},
         { OP_ColumnName,  3, 0,       "notnull"},
         { OP_ColumnName,  4, 0,       "dflt_value"},
-        { OP_ColumnName,  5, 0,       "pk"},
+        { OP_ColumnName,  5, 1,       "pk"},
       };
       int i;
       sqliteVdbeAddOpList(v, ArraySize(tableInfoPreface), tableInfoPreface);
@@ -373,7 +373,7 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
       static VdbeOp tableInfoPreface[] = {
         { OP_ColumnName,  0, 0,       "seqno"},
         { OP_ColumnName,  1, 0,       "cid"},
-        { OP_ColumnName,  2, 0,       "name"},
+        { OP_ColumnName,  2, 1,       "name"},
       };
       int i;
       pTab = pIdx->pTable;
@@ -403,7 +403,7 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
       static VdbeOp indexListPreface[] = {
         { OP_ColumnName,  0, 0,       "seq"},
         { OP_ColumnName,  1, 0,       "name"},
-        { OP_ColumnName,  2, 0,       "unique"},
+        { OP_ColumnName,  2, 1,       "unique"},
       };
 
       sqliteVdbeAddOpList(v, ArraySize(indexListPreface), indexListPreface);
@@ -434,7 +434,7 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
         { OP_ColumnName,  1, 0,       "seq"},
         { OP_ColumnName,  2, 0,       "table"},
         { OP_ColumnName,  3, 0,       "from"},
-        { OP_ColumnName,  4, 0,       "to"},
+        { OP_ColumnName,  4, 1,       "to"},
       };
 
       sqliteVdbeAddOpList(v, ArraySize(indexListPreface), indexListPreface);
@@ -463,7 +463,7 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
     static VdbeOp indexListPreface[] = {
       { OP_ColumnName,  0, 0,       "seq"},
       { OP_ColumnName,  1, 0,       "name"},
-      { OP_ColumnName,  2, 0,       "file"},
+      { OP_ColumnName,  2, 1,       "file"},
     };
 
     sqliteVdbeAddOpList(v, ArraySize(indexListPreface), indexListPreface);
@@ -494,7 +494,7 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
   */
   if( sqliteStrICmp(zLeft, "temp_store")==0 ){
     static VdbeOp getTmpDbLoc[] = {
-      { OP_ColumnName,  0, 0,        "temp_store"},
+      { OP_ColumnName,  0, 1,        "temp_store"},
       { OP_Callback,    1, 0,        0},
     };
     if( pRight->z==pLeft->z ){
@@ -522,7 +522,7 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
   */
   if( sqliteStrICmp(zLeft, "default_temp_store")==0 ){
     static VdbeOp getTmpDbLoc[] = {
-      { OP_ColumnName,  0, 0,        "temp_store"},
+      { OP_ColumnName,  0, 1,        "temp_store"},
       { OP_ReadCookie,  0, 5,        0},
       { OP_Callback,    1, 0,        0}};
     if( pRight->z==pLeft->z ){
@@ -561,7 +561,7 @@ void sqlitePragma(Parse *pParse, Token *pLeft, Token *pRight, int minusFlag){
     static VdbeOp initCode[] = {
       { OP_Integer,     0, 0,        0},
       { OP_MemStore,    0, 1,        0},
-      { OP_ColumnName,  0, 0,        "integrity_check"},
+      { OP_ColumnName,  0, 1,        "integrity_check"},
     };
 
     /* Code to do an BTree integrity check on a single database file.

diff --git a/src/select.c b/src/select.c
index 55c9812a8dc4ca7129349bac0e5f17da6a752169..95b5841d54db7d2ef1267dc5e955a3660603daad 100644 (file)
--- a/src/select.c
+++ b/src/select.c
@@ -12,7 +12,7 @@
 ** This file contains C code routines that are called by the parser
 ** to handle SELECT statements in SQLite.
 **
-** $Id: select.c,v 1.155 2004/02/14 23:59:58 drh Exp $
+** $Id: select.c,v 1.156 2004/02/16 03:44:02 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -689,17 +689,19 @@ static void generateColumnNames(
 ){
   Vdbe *v = pParse->pVdbe;
   int i, j;
+  assert( v!=0 );
   if( pParse->colNamesSet || v==0 || sqlite_malloc_failed ) return;
   pParse->colNamesSet = 1;
   for(i=0; i<pEList->nExpr; i++){
     Expr *p;
     char *zType = 0;
     int showFullNames;
+    int p2 = i==pEList->nExpr-1;
     p = pEList->a[i].pExpr;
     if( p==0 ) continue;
     if( pEList->a[i].zName ){
       char *zName = pEList->a[i].zName;
-      sqliteVdbeAddOp(v, OP_ColumnName, i, 0);
+      sqliteVdbeAddOp(v, OP_ColumnName, i, p2);
       sqliteVdbeChangeP3(v, -1, zName, strlen(zName));
       continue;
     }
@@ -721,7 +723,7 @@ static void generateColumnNames(
         zType = pTab->aCol[iCol].zType;
       }
       if( p->span.z && p->span.z[0] && !showFullNames ){
-        int addr = sqliteVdbeAddOp(v,OP_ColumnName, i, 0);
+        int addr = sqliteVdbeAddOp(v,OP_ColumnName, i, p2);
         sqliteVdbeChangeP3(v, -1, p->span.z, p->span.n);
         sqliteVdbeCompressSpace(v, addr);
       }else if( pTabList->nSrc>1 || showFullNames ){
@@ -731,22 +733,22 @@ static void generateColumnNames(
         zTab = pTabList->a[j].zAlias;
         if( showFullNames || zTab==0 ) zTab = pTab->zName;
         sqliteSetString(&zName, zTab, ".", zCol, 0);
-        sqliteVdbeAddOp(v, OP_ColumnName, i, 0);
+        sqliteVdbeAddOp(v, OP_ColumnName, i, p2);
         sqliteVdbeChangeP3(v, -1, zName, strlen(zName));
         sqliteFree(zName);
       }else{
-        sqliteVdbeAddOp(v, OP_ColumnName, i, 0);
+        sqliteVdbeAddOp(v, OP_ColumnName, i, p2);
         sqliteVdbeChangeP3(v, -1, zCol, 0);
       }
     }else if( p->span.z && p->span.z[0] ){
-      int addr = sqliteVdbeAddOp(v,OP_ColumnName, i, 0);
+      int addr = sqliteVdbeAddOp(v,OP_ColumnName, i, p2);
       sqliteVdbeChangeP3(v, -1, p->span.z, p->span.n);
       sqliteVdbeCompressSpace(v, addr);
     }else{
       char zName[30];
       assert( p->op!=TK_COLUMN || pTabList==0 );
       sprintf(zName, "column%d", i+1);
-      sqliteVdbeAddOp(v, OP_ColumnName, i, 0);
+      sqliteVdbeAddOp(v, OP_ColumnName, i, p2);
       sqliteVdbeChangeP3(v, -1, zName, strlen(zName));
     }
   }
@@ -1496,12 +1498,6 @@ static int multiSelect(Parse *pParse, Select *p, int eDest, int iParm){
       " do not have the same number of result columns", selectOpName(p->op));
     return 1;
   }
-
-  /* Issue a null callback if that is what the user wants.
-  */
-  if( eDest==SRT_Callback ){
-    sqliteVdbeAddOp(v, OP_NullCallback, p->pEList->nExpr, 0);
-  }
   return 0;
 }
 
@@ -2394,13 +2390,6 @@ int sqliteSelect(
     generateSortTail(p, v, pEList->nExpr, eDest, iParm);
   }
 
-
-  /* Issue a null callback if that is what the user wants.
-  */
-  if( eDest==SRT_Callback ){
-    sqliteVdbeAddOp(v, OP_NullCallback, pEList->nExpr, 0);
-  }
-
   /* If this was a subquery, we have now converted the subquery into a
   ** temporary table.  So delete the subquery structure from the parent
   ** to prevent this subquery from being evaluated again and to force the

diff --git a/src/update.c b/src/update.c
index 9f4fd2d4628990312cba9722c2bfaf4e4d73caef..75f006a665750400abe372c866250d91336d7dfe 100644 (file)
--- a/src/update.c
+++ b/src/update.c
@@ -12,7 +12,7 @@
 ** This file contains C code routines that are called by the parser
 ** to handle UPDATE statements.
 **
-** $Id: update.c,v 1.67 2003/06/01 01:10:33 drh Exp $
+** $Id: update.c,v 1.68 2004/02/16 03:44:02 drh Exp $
 */
 #include "sqliteInt.h"
 
@@ -436,7 +436,7 @@ void sqliteUpdate(
   ** Return the number of rows that were changed.
   */
   if( db->flags & SQLITE_CountRows && !pParse->trigStack ){
-    sqliteVdbeAddOp(v, OP_ColumnName, 0, 0);
+    sqliteVdbeAddOp(v, OP_ColumnName, 0, 1);
     sqliteVdbeChangeP3(v, -1, "rows updated", P3_STATIC);
     sqliteVdbeAddOp(v, OP_Callback, 1, 0);
   }

diff --git a/src/vdbe.c b/src/vdbe.c
index 74c8ed1e4debad7bdf71c980e8e49674bd4958e0..e6731d3f8b629f401482aa82aff5caa48d7b8280 100644 (file)
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -43,7 +43,7 @@
 ** in this file for details.  If in doubt, do not deviate from existing
 ** commenting and indentation practices when changing or adding code.
 **
-** $Id: vdbe.c,v 1.264 2004/02/14 23:59:58 drh Exp $
+** $Id: vdbe.c,v 1.265 2004/02/16 03:44:02 drh Exp $
 */
 #include "sqliteInt.h"
 #include "os.h"
@@ -837,15 +837,21 @@ case OP_Push: {
 }
 
 
-/* Opcode: ColumnName P1 * P3
+/* Opcode: ColumnName P1 P2 P3
 **
 ** P3 becomes the P1-th column name (first is 0).  An array of pointers
 ** to all column names is passed as the 4th parameter to the callback.
+** If P2==1 then this is the last column in the result set and thus the
+** number of columns in the result set will be P1.  There must be at least
+** one OP_ColumnName with a P2==1 before invoking OP_Callback and the
+** number of columns specified in OP_Callback must one more than the P1
+** value of the OP_ColumnName that has P2==1.
 */
 case OP_ColumnName: {
   assert( pOp->p1>=0 && pOp->p1<p->nOp );
   p->azColName[pOp->p1] = pOp->p3;
   p->nCallback = 0;
+  if( pOp->p2 ) p->nResColumn = pOp->p1+1;
   break;
 }
 
@@ -873,42 +879,13 @@ case OP_Callback: {
   azArgv[i] = 0;
   p->nCallback++;
   p->azResColumn = azArgv;
-  p->nResColumn = pOp->p1;
+  assert( p->nResColumn==pOp->p1 );
   p->popStack = pOp->p1;
   p->pc = pc + 1;
   p->pTos = pTos;
   return SQLITE_ROW;
 }
 
-/* Opcode: NullCallback P1 * *
-**
-** Invoke the callback function once with the 2nd argument (the
-** number of columns) equal to P1 and with the 4th argument (the
-** names of the columns) set according to prior OP_ColumnName
-** instructions.  This is all like the regular
-** OP_Callback or OP_SortCallback opcodes.  But the 3rd argument
-** which normally contains a pointer to an array of pointers to
-** data is NULL.
-**
-** The callback is only invoked if there have been no prior calls
-** to OP_Callback or OP_SortCallback.
-**
-** This opcode is used to report the number and names of columns
-** in cases where the result set is empty.
-*/
-case OP_NullCallback: {
-  p->nResColumn = pOp->p1;
-  if( p->nCallback==0 && (db->flags & SQLITE_NullCallback)!=0 ){
-    p->azResColumn = 0;
-    p->popStack = 0;
-    p->pc = pc + 1;
-    p->pTos = pTos;
-    p->nCallback++;
-    return SQLITE_ROW;
-  }
-  break;
-}
-
 /* Opcode: Concat P1 P2 P3
 **
 ** Look at the first P1 elements of the stack.  Append them all 
@@ -4076,7 +4053,7 @@ case OP_SortCallback: {
   p->nCallback++;
   p->pc = pc+1;
   p->azResColumn = (char**)pTos->z;
-  p->nResColumn = pOp->p1;
+  assert( p->nResColumn==pOp->p1 );
   p->popStack = 1;
   p->pTos = pTos;
   return SQLITE_ROW;