| 2 |      1 | /*
 | 
|  |      2 | ** 2001 September 15
 | 
|  |      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 | ** This file contains C code routines that are called by the parser
 | 
|  |     13 | ** to handle UPDATE statements.
 | 
|  |     14 | **
 | 
|  |     15 | ** $Id: update.cpp 1282 2008-11-13 09:31:33Z LarsPson $
 | 
|  |     16 | */
 | 
|  |     17 | #include "sqliteInt.h"
 | 
|  |     18 | 
 | 
|  |     19 | #ifndef SQLITE_OMIT_VIRTUALTABLE
 | 
|  |     20 | /* Forward declaration */
 | 
|  |     21 | static void updateVirtualTable(
 | 
|  |     22 |   Parse *pParse,       /* The parsing context */
 | 
|  |     23 |   SrcList *pSrc,       /* The virtual table to be modified */
 | 
|  |     24 |   Table *pTab,         /* The virtual table */
 | 
|  |     25 |   ExprList *pChanges,  /* The columns to change in the UPDATE statement */
 | 
|  |     26 |   Expr *pRowidExpr,    /* Expression used to recompute the rowid */
 | 
|  |     27 |   int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
 | 
|  |     28 |   Expr *pWhere         /* WHERE clause of the UPDATE statement */
 | 
|  |     29 | );
 | 
|  |     30 | #endif /* SQLITE_OMIT_VIRTUALTABLE */
 | 
|  |     31 | 
 | 
|  |     32 | /*
 | 
|  |     33 | ** The most recently coded instruction was an OP_Column to retrieve the
 | 
|  |     34 | ** i-th column of table pTab. This routine sets the P3 parameter of the 
 | 
|  |     35 | ** OP_Column to the default value, if any.
 | 
|  |     36 | **
 | 
|  |     37 | ** The default value of a column is specified by a DEFAULT clause in the 
 | 
|  |     38 | ** column definition. This was either supplied by the user when the table
 | 
|  |     39 | ** was created, or added later to the table definition by an ALTER TABLE
 | 
|  |     40 | ** command. If the latter, then the row-records in the table btree on disk
 | 
|  |     41 | ** may not contain a value for the column and the default value, taken
 | 
|  |     42 | ** from the P3 parameter of the OP_Column instruction, is returned instead.
 | 
|  |     43 | ** If the former, then all row-records are guaranteed to include a value
 | 
|  |     44 | ** for the column and the P3 value is not required.
 | 
|  |     45 | **
 | 
|  |     46 | ** Column definitions created by an ALTER TABLE command may only have 
 | 
|  |     47 | ** literal default values specified: a number, null or a string. (If a more
 | 
|  |     48 | ** complicated default expression value was provided, it is evaluated 
 | 
|  |     49 | ** when the ALTER TABLE is executed and one of the literal values written
 | 
|  |     50 | ** into the sqlite_master table.)
 | 
|  |     51 | **
 | 
|  |     52 | ** Therefore, the P3 parameter is only required if the default value for
 | 
|  |     53 | ** the column is a literal number, string or null. The sqlite3ValueFromExpr()
 | 
|  |     54 | ** function is capable of transforming these types of expressions into
 | 
|  |     55 | ** sqlite3_value objects.
 | 
|  |     56 | */
 | 
|  |     57 | void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){
 | 
|  |     58 |   if( pTab && !pTab->pSelect ){
 | 
|  |     59 |     sqlite3_value *pValue;
 | 
|  |     60 |     u8 enc = ENC(sqlite3VdbeDb(v));
 | 
|  |     61 |     Column *pCol = &pTab->aCol[i];
 | 
|  |     62 |     assert( i<pTab->nCol );
 | 
|  |     63 |     sqlite3ValueFromExpr(sqlite3VdbeDb(v), pCol->pDflt, enc, pCol->affinity, &pValue);
 | 
|  |     64 |     if( pValue ){
 | 
|  |     65 |       sqlite3VdbeChangeP3(v, -1, (const char *)pValue, P3_MEM);
 | 
|  |     66 |     }else{
 | 
|  |     67 |       VdbeComment((v, "# %s.%s", pTab->zName, pCol->zName));
 | 
|  |     68 |     }
 | 
|  |     69 |   }
 | 
|  |     70 | }
 | 
|  |     71 | 
 | 
|  |     72 | /*
 | 
|  |     73 | ** Process an UPDATE statement.
 | 
|  |     74 | **
 | 
|  |     75 | **   UPDATE OR IGNORE table_wxyz SET a=b, c=d WHERE e<5 AND f NOT NULL;
 | 
|  |     76 | **          \_______/ \________/     \______/       \________________/
 | 
|  |     77 | *            onError   pTabList      pChanges             pWhere
 | 
|  |     78 | */
 | 
|  |     79 | void sqlite3Update(
 | 
|  |     80 |   Parse *pParse,         /* The parser context */
 | 
|  |     81 |   SrcList *pTabList,     /* The table in which we should change things */
 | 
|  |     82 |   ExprList *pChanges,    /* Things to be changed */
 | 
|  |     83 |   Expr *pWhere,          /* The WHERE clause.  May be null */
 | 
|  |     84 |   int onError            /* How to handle constraint errors */
 | 
|  |     85 | ){
 | 
|  |     86 |   int i, j;              /* Loop counters */
 | 
|  |     87 |   Table *pTab;           /* The table to be updated */
 | 
|  |     88 |   int addr = 0;          /* VDBE instruction address of the start of the loop */
 | 
|  |     89 |   WhereInfo *pWInfo;     /* Information about the WHERE clause */
 | 
|  |     90 |   Vdbe *v;               /* The virtual database engine */
 | 
|  |     91 |   Index *pIdx;           /* For looping over indices */
 | 
|  |     92 |   int nIdx;              /* Number of indices that need updating */
 | 
|  |     93 |   int nIdxTotal;         /* Total number of indices */
 | 
|  |     94 |   int iCur;              /* VDBE Cursor number of pTab */
 | 
|  |     95 |   sqlite3 *db;           /* The database structure */
 | 
|  |     96 |   Index **apIdx = 0;     /* An array of indices that need updating too */
 | 
|  |     97 |   char *aIdxUsed = 0;    /* aIdxUsed[i]==1 if the i-th index is used */
 | 
|  |     98 |   int *aXRef = 0;        /* aXRef[i] is the index in pChanges->a[] of the
 | 
|  |     99 |                          ** an expression for the i-th column of the table.
 | 
|  |    100 |                          ** aXRef[i]==-1 if the i-th column is not changed. */
 | 
|  |    101 |   int chngRowid;         /* True if the record number is being changed */
 | 
|  |    102 |   Expr *pRowidExpr = 0;  /* Expression defining the new record number */
 | 
|  |    103 |   int openAll = 0;       /* True if all indices need to be opened */
 | 
|  |    104 |   AuthContext sContext;  /* The authorization context */
 | 
|  |    105 |   NameContext sNC;       /* The name-context to resolve expressions in */
 | 
|  |    106 |   int iDb;               /* Database containing the table being updated */
 | 
|  |    107 |   int memCnt = 0;        /* Memory cell used for counting rows changed */
 | 
|  |    108 |   int mem1;      /* Memory address storing the rowid for next row to update */
 | 
|  |    109 | 
 | 
|  |    110 | #ifndef SQLITE_OMIT_TRIGGER
 | 
|  |    111 |   int isView;                  /* Trying to update a view */
 | 
|  |    112 |   int triggers_exist = 0;      /* True if any row triggers exist */
 | 
|  |    113 | #endif
 | 
|  |    114 | 
 | 
|  |    115 |   int newIdx      = -1;  /* index of trigger "new" temp table       */
 | 
|  |    116 |   int oldIdx      = -1;  /* index of trigger "old" temp table       */
 | 
|  |    117 | 
 | 
|  |    118 |   sContext.pParse = 0;
 | 
|  |    119 |   db = pParse->db;
 | 
|  |    120 |   if( pParse->nErr || db->mallocFailed ){
 | 
|  |    121 |     goto update_cleanup;
 | 
|  |    122 |   }
 | 
|  |    123 |   assert( pTabList->nSrc==1 );
 | 
|  |    124 | 
 | 
|  |    125 |   /* Locate the table which we want to update. 
 | 
|  |    126 |   */
 | 
|  |    127 |   pTab = sqlite3SrcListLookup(pParse, pTabList);
 | 
|  |    128 |   if( pTab==0 ) goto update_cleanup;
 | 
|  |    129 |   iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
 | 
|  |    130 | 
 | 
|  |    131 |   /* Figure out if we have any triggers and if the table being
 | 
|  |    132 |   ** updated is a view
 | 
|  |    133 |   */
 | 
|  |    134 | #ifndef SQLITE_OMIT_TRIGGER
 | 
|  |    135 |   triggers_exist = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges);
 | 
|  |    136 |   isView = pTab->pSelect!=0;
 | 
|  |    137 | #else
 | 
|  |    138 | # define triggers_exist 0
 | 
|  |    139 | # define isView 0
 | 
|  |    140 | #endif
 | 
|  |    141 | #ifdef SQLITE_OMIT_VIEW
 | 
|  |    142 | # undef isView
 | 
|  |    143 | # define isView 0
 | 
|  |    144 | #endif
 | 
|  |    145 | 
 | 
|  |    146 |   if( sqlite3IsReadOnly(pParse, pTab, triggers_exist) ){
 | 
|  |    147 |     goto update_cleanup;
 | 
|  |    148 |   }
 | 
|  |    149 |   if( sqlite3ViewGetColumnNames(pParse, pTab) ){
 | 
|  |    150 |     goto update_cleanup;
 | 
|  |    151 |   }
 | 
|  |    152 |   aXRef = (int*)sqlite3DbMallocRaw(db, sizeof(int) * pTab->nCol );
 | 
|  |    153 |   if( aXRef==0 ) goto update_cleanup;
 | 
|  |    154 |   for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;
 | 
|  |    155 | 
 | 
|  |    156 |   /* If there are FOR EACH ROW triggers, allocate cursors for the
 | 
|  |    157 |   ** special OLD and NEW tables
 | 
|  |    158 |   */
 | 
|  |    159 |   if( triggers_exist ){
 | 
|  |    160 |     newIdx = pParse->nTab++;
 | 
|  |    161 |     oldIdx = pParse->nTab++;
 | 
|  |    162 |   }
 | 
|  |    163 | 
 | 
|  |    164 |   /* Allocate a cursors for the main database table and for all indices.
 | 
|  |    165 |   ** The index cursors might not be used, but if they are used they
 | 
|  |    166 |   ** need to occur right after the database cursor.  So go ahead and
 | 
|  |    167 |   ** allocate enough space, just in case.
 | 
|  |    168 |   */
 | 
|  |    169 |   pTabList->a[0].iCursor = iCur = pParse->nTab++;
 | 
|  |    170 |   for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
 | 
|  |    171 |     pParse->nTab++;
 | 
|  |    172 |   }
 | 
|  |    173 | 
 | 
|  |    174 |   /* Initialize the name-context */
 | 
|  |    175 |   memset(&sNC, 0, sizeof(sNC));
 | 
|  |    176 |   sNC.pParse = pParse;
 | 
|  |    177 |   sNC.pSrcList = pTabList;
 | 
|  |    178 | 
 | 
|  |    179 |   /* Resolve the column names in all the expressions of the
 | 
|  |    180 |   ** of the UPDATE statement.  Also find the column index
 | 
|  |    181 |   ** for each column to be updated in the pChanges array.  For each
 | 
|  |    182 |   ** column to be updated, make sure we have authorization to change
 | 
|  |    183 |   ** that column.
 | 
|  |    184 |   */
 | 
|  |    185 |   chngRowid = 0;
 | 
|  |    186 |   for(i=0; i<pChanges->nExpr; i++){
 | 
|  |    187 |     if( sqlite3ExprResolveNames(&sNC, pChanges->a[i].pExpr) ){
 | 
|  |    188 |       goto update_cleanup;
 | 
|  |    189 |     }
 | 
|  |    190 |     for(j=0; j<pTab->nCol; j++){
 | 
|  |    191 |       if( sqlite3StrICmp(pTab->aCol[j].zName, pChanges->a[i].zName)==0 ){
 | 
|  |    192 |         if( j==pTab->iPKey ){
 | 
|  |    193 |           chngRowid = 1;
 | 
|  |    194 |           pRowidExpr = pChanges->a[i].pExpr;
 | 
|  |    195 |         }
 | 
|  |    196 |         aXRef[j] = i;
 | 
|  |    197 |         break;
 | 
|  |    198 |       }
 | 
|  |    199 |     }
 | 
|  |    200 |     if( j>=pTab->nCol ){
 | 
|  |    201 |       if( sqlite3IsRowid(pChanges->a[i].zName) ){
 | 
|  |    202 |         chngRowid = 1;
 | 
|  |    203 |         pRowidExpr = pChanges->a[i].pExpr;
 | 
|  |    204 |       }else{
 | 
|  |    205 |         sqlite3ErrorMsg(pParse, "no such column: %s", pChanges->a[i].zName);
 | 
|  |    206 |         goto update_cleanup;
 | 
|  |    207 |       }
 | 
|  |    208 |     }
 | 
|  |    209 | #ifndef SQLITE_OMIT_AUTHORIZATION
 | 
|  |    210 |     {
 | 
|  |    211 |       int rc;
 | 
|  |    212 |       rc = sqlite3AuthCheck(pParse, SQLITE_UPDATE, pTab->zName,
 | 
|  |    213 |                            pTab->aCol[j].zName, db->aDb[iDb].zName);
 | 
|  |    214 |       if( rc==SQLITE_DENY ){
 | 
|  |    215 |         goto update_cleanup;
 | 
|  |    216 |       }else if( rc==SQLITE_IGNORE ){
 | 
|  |    217 |         aXRef[j] = -1;
 | 
|  |    218 |       }
 | 
|  |    219 |     }
 | 
|  |    220 | #endif
 | 
|  |    221 |   }
 | 
|  |    222 | 
 | 
|  |    223 |   /* Allocate memory for the array apIdx[] and fill it with pointers to every
 | 
|  |    224 |   ** index that needs to be updated.  Indices only need updating if their
 | 
|  |    225 |   ** key includes one of the columns named in pChanges or if the record
 | 
|  |    226 |   ** number of the original table entry is changing.
 | 
|  |    227 |   */
 | 
|  |    228 |   for(nIdx=nIdxTotal=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdxTotal++){
 | 
|  |    229 |     if( chngRowid ){
 | 
|  |    230 |       i = 0;
 | 
|  |    231 |     }else {
 | 
|  |    232 |       for(i=0; i<pIdx->nColumn; i++){
 | 
|  |    233 |         if( aXRef[pIdx->aiColumn[i]]>=0 ) break;
 | 
|  |    234 |       }
 | 
|  |    235 |     }
 | 
|  |    236 |     if( i<pIdx->nColumn ) nIdx++;
 | 
|  |    237 |   }
 | 
|  |    238 |   if( nIdxTotal>0 ){
 | 
|  |    239 |     apIdx = (Index**)sqlite3DbMallocRaw(db, sizeof(Index*) * nIdx + nIdxTotal );
 | 
|  |    240 |     if( apIdx==0 ) goto update_cleanup;
 | 
|  |    241 |     aIdxUsed = (char*)&apIdx[nIdx];
 | 
|  |    242 |   }
 | 
|  |    243 |   for(nIdx=j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
 | 
|  |    244 |     if( chngRowid ){
 | 
|  |    245 |       i = 0;
 | 
|  |    246 |     }else{
 | 
|  |    247 |       for(i=0; i<pIdx->nColumn; i++){
 | 
|  |    248 |         if( aXRef[pIdx->aiColumn[i]]>=0 ) break;
 | 
|  |    249 |       }
 | 
|  |    250 |     }
 | 
|  |    251 |     if( i<pIdx->nColumn ){
 | 
|  |    252 |       apIdx[nIdx++] = pIdx;
 | 
|  |    253 |       aIdxUsed[j] = 1;
 | 
|  |    254 |     }else{
 | 
|  |    255 |       aIdxUsed[j] = 0;
 | 
|  |    256 |     }
 | 
|  |    257 |   }
 | 
|  |    258 | 
 | 
|  |    259 |   /* Begin generating code.
 | 
|  |    260 |   */
 | 
|  |    261 |   v = sqlite3GetVdbe(pParse);
 | 
|  |    262 |   if( v==0 ) goto update_cleanup;
 | 
|  |    263 |   if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
 | 
|  |    264 |   sqlite3BeginWriteOperation(pParse, 1, iDb);
 | 
|  |    265 |   mem1 = pParse->nMem++;
 | 
|  |    266 | 
 | 
|  |    267 | #ifndef SQLITE_OMIT_VIRTUALTABLE
 | 
|  |    268 |   /* Virtual tables must be handled separately */
 | 
|  |    269 |   if( IsVirtual(pTab) ){
 | 
|  |    270 |     updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
 | 
|  |    271 |                        pWhere);
 | 
|  |    272 |     pWhere = 0;
 | 
|  |    273 |     pTabList = 0;
 | 
|  |    274 |     goto update_cleanup;
 | 
|  |    275 |   }
 | 
|  |    276 | #endif
 | 
|  |    277 | 
 | 
|  |    278 |   /* Resolve the column names in all the expressions in the
 | 
|  |    279 |   ** WHERE clause.
 | 
|  |    280 |   */
 | 
|  |    281 |   if( sqlite3ExprResolveNames(&sNC, pWhere) ){
 | 
|  |    282 |     goto update_cleanup;
 | 
|  |    283 |   }
 | 
|  |    284 | 
 | 
|  |    285 |   /* Start the view context
 | 
|  |    286 |   */
 | 
|  |    287 |   if( isView ){
 | 
|  |    288 |     sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
 | 
|  |    289 |   }
 | 
|  |    290 | 
 | 
|  |    291 |   /* If we are trying to update a view, realize that view into
 | 
|  |    292 |   ** a ephemeral table.
 | 
|  |    293 |   */
 | 
|  |    294 |   if( isView ){
 | 
|  |    295 |     Select *pView;
 | 
|  |    296 |     pView = sqlite3SelectDup(db, pTab->pSelect);
 | 
|  |    297 |     sqlite3Select(pParse, pView, SRT_EphemTab, iCur, 0, 0, 0, 0);
 | 
|  |    298 |     sqlite3SelectDelete(pView);
 | 
|  |    299 |   }
 | 
|  |    300 | 
 | 
|  |    301 |   /* Begin the database scan
 | 
|  |    302 |   */
 | 
|  |    303 |   pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0);
 | 
|  |    304 |   if( pWInfo==0 ) goto update_cleanup;
 | 
|  |    305 | 
 | 
|  |    306 |   /* Remember the rowid of every item to be updated.
 | 
|  |    307 |   */
 | 
|  |    308 |   sqlite3VdbeAddOp(v, IsVirtual(pTab) ? OP_VRowid : OP_Rowid, iCur, 0);
 | 
|  |    309 |   sqlite3VdbeAddOp(v, OP_FifoWrite, 0, 0);
 | 
|  |    310 | 
 | 
|  |    311 |   /* End the database scan loop.
 | 
|  |    312 |   */
 | 
|  |    313 |   sqlite3WhereEnd(pWInfo);
 | 
|  |    314 | 
 | 
|  |    315 |   /* Initialize the count of updated rows
 | 
|  |    316 |   */
 | 
|  |    317 |   if( db->flags & SQLITE_CountRows && !pParse->trigStack ){
 | 
|  |    318 |     memCnt = pParse->nMem++;
 | 
|  |    319 |     sqlite3VdbeAddOp(v, OP_MemInt, 0, memCnt);
 | 
|  |    320 |   }
 | 
|  |    321 | 
 | 
|  |    322 |   if( triggers_exist ){
 | 
|  |    323 |     
 | 
|  |    324 |     /* Create pseudo-tables for NEW and OLD
 | 
|  |    325 |     */
 | 
|  |    326 |     sqlite3VdbeAddOp(v, OP_OpenPseudo, oldIdx, 0);
 | 
|  |    327 |     sqlite3VdbeAddOp(v, OP_SetNumColumns, oldIdx, pTab->nCol);
 | 
|  |    328 |     sqlite3VdbeAddOp(v, OP_OpenPseudo, newIdx, 0);
 | 
|  |    329 |     sqlite3VdbeAddOp(v, OP_SetNumColumns, newIdx, pTab->nCol);
 | 
|  |    330 | 
 | 
|  |    331 |     /* The top of the update loop for when there are triggers.
 | 
|  |    332 |     */
 | 
|  |    333 |     addr = sqlite3VdbeAddOp(v, OP_FifoRead, 0, 0);
 | 
|  |    334 |     sqlite3VdbeAddOp(v, OP_StackDepth, -1, 0);
 | 
|  |    335 |     sqlite3VdbeAddOp(v, OP_MemStore, mem1, 0);
 | 
|  |    336 |     
 | 
|  |    337 |     if( !isView ){
 | 
|  |    338 |       /* Open a cursor and make it point to the record that is
 | 
|  |    339 |       ** being updated.
 | 
|  |    340 |       */
 | 
|  |    341 |       sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenRead);
 | 
|  |    342 |     }
 | 
|  |    343 |     sqlite3VdbeAddOp(v, OP_NotExists, iCur, addr);
 | 
|  |    344 | 
 | 
|  |    345 |     /* Generate the OLD table
 | 
|  |    346 |     */
 | 
|  |    347 |     sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0);
 | 
|  |    348 |     sqlite3VdbeAddOp(v, OP_RowData, iCur, 0);
 | 
|  |    349 |     sqlite3VdbeAddOp(v, OP_Insert, oldIdx, 0);
 | 
|  |    350 | 
 | 
|  |    351 |     /* Generate the NEW table
 | 
|  |    352 |     */
 | 
|  |    353 |     if( chngRowid ){
 | 
|  |    354 |       sqlite3ExprCodeAndCache(pParse, pRowidExpr);
 | 
|  |    355 |     }else{
 | 
|  |    356 |       sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0);
 | 
|  |    357 |     }
 | 
|  |    358 |     for(i=0; i<pTab->nCol; i++){
 | 
|  |    359 |       if( i==pTab->iPKey ){
 | 
|  |    360 |         sqlite3VdbeAddOp(v, OP_Null, 0, 0);
 | 
|  |    361 |         continue;
 | 
|  |    362 |       }
 | 
|  |    363 |       j = aXRef[i];
 | 
|  |    364 |       if( j<0 ){
 | 
|  |    365 |         sqlite3VdbeAddOp(v, OP_Column, iCur, i);
 | 
|  |    366 |         sqlite3ColumnDefault(v, pTab, i);
 | 
|  |    367 |       }else{
 | 
|  |    368 |         sqlite3ExprCodeAndCache(pParse, pChanges->a[j].pExpr);
 | 
|  |    369 |       }
 | 
|  |    370 |     }
 | 
|  |    371 |     sqlite3VdbeAddOp(v, OP_MakeRecord, pTab->nCol, 0);
 | 
|  |    372 |     if( !isView ){
 | 
|  |    373 |       sqlite3TableAffinityStr(v, pTab);
 | 
|  |    374 |     }
 | 
|  |    375 |     if( pParse->nErr ) goto update_cleanup;
 | 
|  |    376 |     sqlite3VdbeAddOp(v, OP_Insert, newIdx, 0);
 | 
|  |    377 |     if( !isView ){
 | 
|  |    378 |       sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
 | 
|  |    379 |     }
 | 
|  |    380 | 
 | 
|  |    381 |     /* Fire the BEFORE and INSTEAD OF triggers
 | 
|  |    382 |     */
 | 
|  |    383 |     if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_BEFORE, pTab,
 | 
|  |    384 |           newIdx, oldIdx, onError, addr) ){
 | 
|  |    385 |       goto update_cleanup;
 | 
|  |    386 |     }
 | 
|  |    387 |     
 | 
|  |    388 |     if( !isView ){
 | 
|  |    389 |       sqlite3VdbeAddOp(v, OP_MemLoad, mem1, 0);
 | 
|  |    390 |     }
 | 
|  |    391 |   }
 | 
|  |    392 | 
 | 
|  |    393 |   if( !isView && !IsVirtual(pTab) ){
 | 
|  |    394 |     /* 
 | 
|  |    395 |     ** Open every index that needs updating.  Note that if any
 | 
|  |    396 |     ** index could potentially invoke a REPLACE conflict resolution 
 | 
|  |    397 |     ** action, then we need to open all indices because we might need
 | 
|  |    398 |     ** to be deleting some records.
 | 
|  |    399 |     */
 | 
|  |    400 |     sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenWrite); 
 | 
|  |    401 |     if( onError==OE_Replace ){
 | 
|  |    402 |       openAll = 1;
 | 
|  |    403 |     }else{
 | 
|  |    404 |       openAll = 0;
 | 
|  |    405 |       for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
 | 
|  |    406 |         if( pIdx->onError==OE_Replace ){
 | 
|  |    407 |           openAll = 1;
 | 
|  |    408 |           break;
 | 
|  |    409 |         }
 | 
|  |    410 |       }
 | 
|  |    411 |     }
 | 
|  |    412 |     for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
 | 
|  |    413 |       if( openAll || aIdxUsed[i] ){
 | 
|  |    414 |         KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
 | 
|  |    415 |         sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
 | 
|  |    416 |         sqlite3VdbeOp3(v, OP_OpenWrite, iCur+i+1, pIdx->tnum,
 | 
|  |    417 |                        (char*)pKey, P3_KEYINFO_HANDOFF);
 | 
|  |    418 |         assert( pParse->nTab>iCur+i+1 );
 | 
|  |    419 |       }
 | 
|  |    420 |     }
 | 
|  |    421 | 
 | 
|  |    422 |     /* Loop over every record that needs updating.  We have to load
 | 
|  |    423 |     ** the old data for each record to be updated because some columns
 | 
|  |    424 |     ** might not change and we will need to copy the old value.
 | 
|  |    425 |     ** Also, the old data is needed to delete the old index entries.
 | 
|  |    426 |     ** So make the cursor point at the old record.
 | 
|  |    427 |     */
 | 
|  |    428 |     if( !triggers_exist ){
 | 
|  |    429 |       addr = sqlite3VdbeAddOp(v, OP_FifoRead, 0, 0);
 | 
|  |    430 |       sqlite3VdbeAddOp(v, OP_StackDepth, -1, 0);
 | 
|  |    431 |       sqlite3VdbeAddOp(v, OP_MemStore, mem1, 0);
 | 
|  |    432 |     }
 | 
|  |    433 |     sqlite3VdbeAddOp(v, OP_NotExists, iCur, addr);
 | 
|  |    434 |     sqlite3VdbeAddOp(v, OP_MemLoad, mem1, 0);
 | 
|  |    435 | 
 | 
|  |    436 |     /* If the record number will change, push the record number as it
 | 
|  |    437 |     ** will be after the update. (The old record number is currently
 | 
|  |    438 |     ** on top of the stack.)
 | 
|  |    439 |     */
 | 
|  |    440 |     if( chngRowid ){
 | 
|  |    441 |       sqlite3ExprCode(pParse, pRowidExpr);
 | 
|  |    442 |       sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
 | 
|  |    443 |     }
 | 
|  |    444 | 
 | 
|  |    445 |     /* Compute new data for this record.  
 | 
|  |    446 |     */
 | 
|  |    447 |     for(i=0; i<pTab->nCol; i++){
 | 
|  |    448 |       if( i==pTab->iPKey ){
 | 
|  |    449 |         sqlite3VdbeAddOp(v, OP_Null, 0, 0);
 | 
|  |    450 |         continue;
 | 
|  |    451 |       }
 | 
|  |    452 |       j = aXRef[i];
 | 
|  |    453 |       if( j<0 ){
 | 
|  |    454 |         sqlite3VdbeAddOp(v, OP_Column, iCur, i);
 | 
|  |    455 |         sqlite3ColumnDefault(v, pTab, i);
 | 
|  |    456 |       }else{
 | 
|  |    457 |         sqlite3ExprCode(pParse, pChanges->a[j].pExpr);
 | 
|  |    458 |       }
 | 
|  |    459 |     }
 | 
|  |    460 | 
 | 
|  |    461 |     /* Do constraint checks
 | 
|  |    462 |     */
 | 
|  |    463 |     sqlite3GenerateConstraintChecks(pParse, pTab, iCur, aIdxUsed, chngRowid, 1,
 | 
|  |    464 |                                    onError, addr);
 | 
|  |    465 | 
 | 
|  |    466 |     /* Delete the old indices for the current record.
 | 
|  |    467 |     */
 | 
|  |    468 |     sqlite3GenerateRowIndexDelete(v, pTab, iCur, aIdxUsed);
 | 
|  |    469 | 
 | 
|  |    470 |     /* If changing the record number, delete the old record.
 | 
|  |    471 |     */
 | 
|  |    472 |     if( chngRowid ){
 | 
|  |    473 |       sqlite3VdbeAddOp(v, OP_Delete, iCur, 0);
 | 
|  |    474 |     }
 | 
|  |    475 | 
 | 
|  |    476 |     /* Create the new index entries and the new record.
 | 
|  |    477 |     */
 | 
|  |    478 |     sqlite3CompleteInsertion(pParse, pTab, iCur, aIdxUsed, chngRowid, 1, -1, 0);
 | 
|  |    479 |   }
 | 
|  |    480 | 
 | 
|  |    481 |   /* Increment the row counter 
 | 
|  |    482 |   */
 | 
|  |    483 |   if( db->flags & SQLITE_CountRows && !pParse->trigStack){
 | 
|  |    484 |     sqlite3VdbeAddOp(v, OP_MemIncr, 1, memCnt);
 | 
|  |    485 |   }
 | 
|  |    486 | 
 | 
|  |    487 |   /* If there are triggers, close all the cursors after each iteration
 | 
|  |    488 |   ** through the loop.  The fire the after triggers.
 | 
|  |    489 |   */
 | 
|  |    490 |   if( triggers_exist ){
 | 
|  |    491 |     if( !isView ){
 | 
|  |    492 |       for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
 | 
|  |    493 |         if( openAll || aIdxUsed[i] )
 | 
|  |    494 |           sqlite3VdbeAddOp(v, OP_Close, iCur+i+1, 0);
 | 
|  |    495 |       }
 | 
|  |    496 |       sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
 | 
|  |    497 |     }
 | 
|  |    498 |     if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_AFTER, pTab, 
 | 
|  |    499 |           newIdx, oldIdx, onError, addr) ){
 | 
|  |    500 |       goto update_cleanup;
 | 
|  |    501 |     }
 | 
|  |    502 |   }
 | 
|  |    503 | 
 | 
|  |    504 |   /* Repeat the above with the next record to be updated, until
 | 
|  |    505 |   ** all record selected by the WHERE clause have been updated.
 | 
|  |    506 |   */
 | 
|  |    507 |   sqlite3VdbeAddOp(v, OP_Goto, 0, addr);
 | 
|  |    508 |   sqlite3VdbeJumpHere(v, addr);
 | 
|  |    509 | 
 | 
|  |    510 |   /* Close all tables if there were no FOR EACH ROW triggers */
 | 
|  |    511 |   if( !triggers_exist ){
 | 
|  |    512 |     for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
 | 
|  |    513 |       if( openAll || aIdxUsed[i] ){
 | 
|  |    514 |         sqlite3VdbeAddOp(v, OP_Close, iCur+i+1, 0);
 | 
|  |    515 |       }
 | 
|  |    516 |     }
 | 
|  |    517 |     sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
 | 
|  |    518 |   }else{
 | 
|  |    519 |     sqlite3VdbeAddOp(v, OP_Close, newIdx, 0);
 | 
|  |    520 |     sqlite3VdbeAddOp(v, OP_Close, oldIdx, 0);
 | 
|  |    521 |   }
 | 
|  |    522 | 
 | 
|  |    523 |   /*
 | 
|  |    524 |   ** Return the number of rows that were changed. If this routine is 
 | 
|  |    525 |   ** generating code because of a call to sqlite3NestedParse(), do not
 | 
|  |    526 |   ** invoke the callback function.
 | 
|  |    527 |   */
 | 
|  |    528 |   if( db->flags & SQLITE_CountRows && !pParse->trigStack && pParse->nested==0 ){
 | 
|  |    529 |     sqlite3VdbeAddOp(v, OP_MemLoad, memCnt, 0);
 | 
|  |    530 |     sqlite3VdbeAddOp(v, OP_Callback, 1, 0);
 | 
|  |    531 |     sqlite3VdbeSetNumCols(v, 1);
 | 
|  |    532 |     sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows updated", P3_STATIC);
 | 
|  |    533 |   }
 | 
|  |    534 | 
 | 
|  |    535 | update_cleanup:
 | 
|  |    536 |   sqlite3AuthContextPop(&sContext);
 | 
|  |    537 |   sqlite3_free(apIdx);
 | 
|  |    538 |   sqlite3_free(aXRef);
 | 
|  |    539 |   sqlite3SrcListDelete(pTabList);
 | 
|  |    540 |   sqlite3ExprListDelete(pChanges);
 | 
|  |    541 |   sqlite3ExprDelete(pWhere);
 | 
|  |    542 |   return;
 | 
|  |    543 | }
 | 
|  |    544 | 
 | 
|  |    545 | #ifndef SQLITE_OMIT_VIRTUALTABLE
 | 
|  |    546 | /*
 | 
|  |    547 | ** Generate code for an UPDATE of a virtual table.
 | 
|  |    548 | **
 | 
|  |    549 | ** The strategy is that we create an ephemerial table that contains
 | 
|  |    550 | ** for each row to be changed:
 | 
|  |    551 | **
 | 
|  |    552 | **   (A)  The original rowid of that row.
 | 
|  |    553 | **   (B)  The revised rowid for the row. (note1)
 | 
|  |    554 | **   (C)  The content of every column in the row.
 | 
|  |    555 | **
 | 
|  |    556 | ** Then we loop over this ephemeral table and for each row in
 | 
|  |    557 | ** the ephermeral table call VUpdate.
 | 
|  |    558 | **
 | 
|  |    559 | ** When finished, drop the ephemeral table.
 | 
|  |    560 | **
 | 
|  |    561 | ** (note1) Actually, if we know in advance that (A) is always the same
 | 
|  |    562 | ** as (B) we only store (A), then duplicate (A) when pulling
 | 
|  |    563 | ** it out of the ephemeral table before calling VUpdate.
 | 
|  |    564 | */
 | 
|  |    565 | static void updateVirtualTable(
 | 
|  |    566 |   Parse *pParse,       /* The parsing context */
 | 
|  |    567 |   SrcList *pSrc,       /* The virtual table to be modified */
 | 
|  |    568 |   Table *pTab,         /* The virtual table */
 | 
|  |    569 |   ExprList *pChanges,  /* The columns to change in the UPDATE statement */
 | 
|  |    570 |   Expr *pRowid,        /* Expression used to recompute the rowid */
 | 
|  |    571 |   int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
 | 
|  |    572 |   Expr *pWhere         /* WHERE clause of the UPDATE statement */
 | 
|  |    573 | ){
 | 
|  |    574 |   Vdbe *v = pParse->pVdbe;  /* Virtual machine under construction */
 | 
|  |    575 |   ExprList *pEList = 0;     /* The result set of the SELECT statement */
 | 
|  |    576 |   Select *pSelect = 0;      /* The SELECT statement */
 | 
|  |    577 |   Expr *pExpr;              /* Temporary expression */
 | 
|  |    578 |   int ephemTab;             /* Table holding the result of the SELECT */
 | 
|  |    579 |   int i;                    /* Loop counter */
 | 
|  |    580 |   int addr;                 /* Address of top of loop */
 | 
|  |    581 |   sqlite3 *db = pParse->db; /* Database connection */
 | 
|  |    582 | 
 | 
|  |    583 |   /* Construct the SELECT statement that will find the new values for
 | 
|  |    584 |   ** all updated rows. 
 | 
|  |    585 |   */
 | 
|  |    586 |   pEList = sqlite3ExprListAppend(pParse, 0, 
 | 
|  |    587 |                                  sqlite3CreateIdExpr(pParse, "_rowid_"), 0);
 | 
|  |    588 |   if( pRowid ){
 | 
|  |    589 |     pEList = sqlite3ExprListAppend(pParse, pEList,
 | 
|  |    590 |                                    sqlite3ExprDup(db, pRowid), 0);
 | 
|  |    591 |   }
 | 
|  |    592 |   assert( pTab->iPKey<0 );
 | 
|  |    593 |   for(i=0; i<pTab->nCol; i++){
 | 
|  |    594 |     if( aXRef[i]>=0 ){
 | 
|  |    595 |       pExpr = sqlite3ExprDup(db, pChanges->a[aXRef[i]].pExpr);
 | 
|  |    596 |     }else{
 | 
|  |    597 |       pExpr = sqlite3CreateIdExpr(pParse, pTab->aCol[i].zName);
 | 
|  |    598 |     }
 | 
|  |    599 |     pEList = sqlite3ExprListAppend(pParse, pEList, pExpr, 0);
 | 
|  |    600 |   }
 | 
|  |    601 |   pSelect = sqlite3SelectNew(pParse, pEList, pSrc, pWhere, 0, 0, 0, 0, 0, 0);
 | 
|  |    602 |   
 | 
|  |    603 |   /* Create the ephemeral table into which the update results will
 | 
|  |    604 |   ** be stored.
 | 
|  |    605 |   */
 | 
|  |    606 |   assert( v );
 | 
|  |    607 |   ephemTab = pParse->nTab++;
 | 
|  |    608 |   sqlite3VdbeAddOp(v, OP_OpenEphemeral, ephemTab, pTab->nCol+1+(pRowid!=0));
 | 
|  |    609 | 
 | 
|  |    610 |   /* fill the ephemeral table 
 | 
|  |    611 |   */
 | 
|  |    612 |   sqlite3Select(pParse, pSelect, SRT_Table, ephemTab, 0, 0, 0, 0);
 | 
|  |    613 | 
 | 
|  |    614 |   /*
 | 
|  |    615 |   ** Generate code to scan the ephemeral table and call VDelete and
 | 
|  |    616 |   ** VInsert
 | 
|  |    617 |   */
 | 
|  |    618 |   sqlite3VdbeAddOp(v, OP_Rewind, ephemTab, 0);
 | 
|  |    619 |   addr = sqlite3VdbeCurrentAddr(v);
 | 
|  |    620 |   sqlite3VdbeAddOp(v, OP_Column,  ephemTab, 0);
 | 
|  |    621 |   if( pRowid ){
 | 
|  |    622 |     sqlite3VdbeAddOp(v, OP_Column, ephemTab, 1);
 | 
|  |    623 |   }else{
 | 
|  |    624 |     sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
 | 
|  |    625 |   }
 | 
|  |    626 |   for(i=0; i<pTab->nCol; i++){
 | 
|  |    627 |     sqlite3VdbeAddOp(v, OP_Column, ephemTab, i+1+(pRowid!=0));
 | 
|  |    628 |   }
 | 
|  |    629 |   pParse->pVirtualLock = pTab;
 | 
|  |    630 |   sqlite3VdbeOp3(v, OP_VUpdate, 0, pTab->nCol+2, 
 | 
|  |    631 |                      (const char*)pTab->pVtab, P3_VTAB);
 | 
|  |    632 |   sqlite3VdbeAddOp(v, OP_Next, ephemTab, addr);
 | 
|  |    633 |   sqlite3VdbeJumpHere(v, addr-1);
 | 
|  |    634 |   sqlite3VdbeAddOp(v, OP_Close, ephemTab, 0);
 | 
|  |    635 | 
 | 
|  |    636 |   /* Cleanup */
 | 
|  |    637 |   sqlite3SelectDelete(pSelect);  
 | 
|  |    638 | }
 | 
|  |    639 | #endif /* SQLITE_OMIT_VIRTUALTABLE */
 |