1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/os/persistentdata/persistentstorage/sql/SQLite/update.c Fri Jun 15 03:10:57 2012 +0200
1.3 @@ -0,0 +1,678 @@
1.4 +/*
1.5 +** 2001 September 15
1.6 +**
1.7 +** The author disclaims copyright to this source code. In place of
1.8 +** a legal notice, here is a blessing:
1.9 +**
1.10 +** May you do good and not evil.
1.11 +** May you find forgiveness for yourself and forgive others.
1.12 +** May you share freely, never taking more than you give.
1.13 +**
1.14 +*************************************************************************
1.15 +** This file contains C code routines that are called by the parser
1.16 +** to handle UPDATE statements.
1.17 +**
1.18 +** $Id: update.c,v 1.181 2008/07/28 19:34:54 drh Exp $
1.19 +*/
1.20 +#include "sqliteInt.h"
1.21 +
1.22 +#ifndef SQLITE_OMIT_VIRTUALTABLE
1.23 +/* Forward declaration */
1.24 +static void updateVirtualTable(
1.25 + Parse *pParse, /* The parsing context */
1.26 + SrcList *pSrc, /* The virtual table to be modified */
1.27 + Table *pTab, /* The virtual table */
1.28 + ExprList *pChanges, /* The columns to change in the UPDATE statement */
1.29 + Expr *pRowidExpr, /* Expression used to recompute the rowid */
1.30 + int *aXRef, /* Mapping from columns of pTab to entries in pChanges */
1.31 + Expr *pWhere /* WHERE clause of the UPDATE statement */
1.32 +);
1.33 +#endif /* SQLITE_OMIT_VIRTUALTABLE */
1.34 +
1.35 +/*
1.36 +** The most recently coded instruction was an OP_Column to retrieve the
1.37 +** i-th column of table pTab. This routine sets the P4 parameter of the
1.38 +** OP_Column to the default value, if any.
1.39 +**
1.40 +** The default value of a column is specified by a DEFAULT clause in the
1.41 +** column definition. This was either supplied by the user when the table
1.42 +** was created, or added later to the table definition by an ALTER TABLE
1.43 +** command. If the latter, then the row-records in the table btree on disk
1.44 +** may not contain a value for the column and the default value, taken
1.45 +** from the P4 parameter of the OP_Column instruction, is returned instead.
1.46 +** If the former, then all row-records are guaranteed to include a value
1.47 +** for the column and the P4 value is not required.
1.48 +**
1.49 +** Column definitions created by an ALTER TABLE command may only have
1.50 +** literal default values specified: a number, null or a string. (If a more
1.51 +** complicated default expression value was provided, it is evaluated
1.52 +** when the ALTER TABLE is executed and one of the literal values written
1.53 +** into the sqlite_master table.)
1.54 +**
1.55 +** Therefore, the P4 parameter is only required if the default value for
1.56 +** the column is a literal number, string or null. The sqlite3ValueFromExpr()
1.57 +** function is capable of transforming these types of expressions into
1.58 +** sqlite3_value objects.
1.59 +*/
1.60 +void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){
1.61 + if( pTab && !pTab->pSelect ){
1.62 + sqlite3_value *pValue;
1.63 + u8 enc = ENC(sqlite3VdbeDb(v));
1.64 + Column *pCol = &pTab->aCol[i];
1.65 + VdbeComment((v, "%s.%s", pTab->zName, pCol->zName));
1.66 + assert( i<pTab->nCol );
1.67 + sqlite3ValueFromExpr(sqlite3VdbeDb(v), pCol->pDflt, enc,
1.68 + pCol->affinity, &pValue);
1.69 + if( pValue ){
1.70 + sqlite3VdbeChangeP4(v, -1, (const char *)pValue, P4_MEM);
1.71 + }
1.72 + }
1.73 +}
1.74 +
1.75 +/*
1.76 +** Process an UPDATE statement.
1.77 +**
1.78 +** UPDATE OR IGNORE table_wxyz SET a=b, c=d WHERE e<5 AND f NOT NULL;
1.79 +** \_______/ \________/ \______/ \________________/
1.80 +* onError pTabList pChanges pWhere
1.81 +*/
1.82 +void sqlite3Update(
1.83 + Parse *pParse, /* The parser context */
1.84 + SrcList *pTabList, /* The table in which we should change things */
1.85 + ExprList *pChanges, /* Things to be changed */
1.86 + Expr *pWhere, /* The WHERE clause. May be null */
1.87 + int onError /* How to handle constraint errors */
1.88 +){
1.89 + int i, j; /* Loop counters */
1.90 + Table *pTab; /* The table to be updated */
1.91 + int addr = 0; /* VDBE instruction address of the start of the loop */
1.92 + WhereInfo *pWInfo; /* Information about the WHERE clause */
1.93 + Vdbe *v; /* The virtual database engine */
1.94 + Index *pIdx; /* For looping over indices */
1.95 + int nIdx; /* Number of indices that need updating */
1.96 + int iCur; /* VDBE Cursor number of pTab */
1.97 + sqlite3 *db; /* The database structure */
1.98 + int *aRegIdx = 0; /* One register assigned to each index to be updated */
1.99 + int *aXRef = 0; /* aXRef[i] is the index in pChanges->a[] of the
1.100 + ** an expression for the i-th column of the table.
1.101 + ** aXRef[i]==-1 if the i-th column is not changed. */
1.102 + int chngRowid; /* True if the record number is being changed */
1.103 + Expr *pRowidExpr = 0; /* Expression defining the new record number */
1.104 + int openAll = 0; /* True if all indices need to be opened */
1.105 + AuthContext sContext; /* The authorization context */
1.106 + NameContext sNC; /* The name-context to resolve expressions in */
1.107 + int iDb; /* Database containing the table being updated */
1.108 + int j1; /* Addresses of jump instructions */
1.109 + int okOnePass; /* True for one-pass algorithm without the FIFO */
1.110 +
1.111 +#ifndef SQLITE_OMIT_TRIGGER
1.112 + int isView; /* Trying to update a view */
1.113 + int triggers_exist = 0; /* True if any row triggers exist */
1.114 +#endif
1.115 + int iBeginAfterTrigger = 0; /* Address of after trigger program */
1.116 + int iEndAfterTrigger = 0; /* Exit of after trigger program */
1.117 + int iBeginBeforeTrigger = 0; /* Address of before trigger program */
1.118 + int iEndBeforeTrigger = 0; /* Exit of before trigger program */
1.119 + u32 old_col_mask = 0; /* Mask of OLD.* columns in use */
1.120 + u32 new_col_mask = 0; /* Mask of NEW.* columns in use */
1.121 +
1.122 + int newIdx = -1; /* index of trigger "new" temp table */
1.123 + int oldIdx = -1; /* index of trigger "old" temp table */
1.124 +
1.125 + /* Register Allocations */
1.126 + int regRowCount = 0; /* A count of rows changed */
1.127 + int regOldRowid; /* The old rowid */
1.128 + int regNewRowid; /* The new rowid */
1.129 + int regData; /* New data for the row */
1.130 +
1.131 + sContext.pParse = 0;
1.132 + db = pParse->db;
1.133 + if( pParse->nErr || db->mallocFailed ){
1.134 + goto update_cleanup;
1.135 + }
1.136 + assert( pTabList->nSrc==1 );
1.137 +
1.138 + /* Locate the table which we want to update.
1.139 + */
1.140 + pTab = sqlite3SrcListLookup(pParse, pTabList);
1.141 + if( pTab==0 ) goto update_cleanup;
1.142 + iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
1.143 +
1.144 + /* Figure out if we have any triggers and if the table being
1.145 + ** updated is a view
1.146 + */
1.147 +#ifndef SQLITE_OMIT_TRIGGER
1.148 + triggers_exist = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges);
1.149 + isView = pTab->pSelect!=0;
1.150 +#else
1.151 +# define triggers_exist 0
1.152 +# define isView 0
1.153 +#endif
1.154 +#ifdef SQLITE_OMIT_VIEW
1.155 +# undef isView
1.156 +# define isView 0
1.157 +#endif
1.158 +
1.159 + if( sqlite3IsReadOnly(pParse, pTab, triggers_exist) ){
1.160 + goto update_cleanup;
1.161 + }
1.162 + if( sqlite3ViewGetColumnNames(pParse, pTab) ){
1.163 + goto update_cleanup;
1.164 + }
1.165 + aXRef = sqlite3DbMallocRaw(db, sizeof(int) * pTab->nCol );
1.166 + if( aXRef==0 ) goto update_cleanup;
1.167 + for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;
1.168 +
1.169 + /* If there are FOR EACH ROW triggers, allocate cursors for the
1.170 + ** special OLD and NEW tables
1.171 + */
1.172 + if( triggers_exist ){
1.173 + newIdx = pParse->nTab++;
1.174 + oldIdx = pParse->nTab++;
1.175 + }
1.176 +
1.177 + /* Allocate a cursors for the main database table and for all indices.
1.178 + ** The index cursors might not be used, but if they are used they
1.179 + ** need to occur right after the database cursor. So go ahead and
1.180 + ** allocate enough space, just in case.
1.181 + */
1.182 + pTabList->a[0].iCursor = iCur = pParse->nTab++;
1.183 + for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
1.184 + pParse->nTab++;
1.185 + }
1.186 +
1.187 + /* Initialize the name-context */
1.188 + memset(&sNC, 0, sizeof(sNC));
1.189 + sNC.pParse = pParse;
1.190 + sNC.pSrcList = pTabList;
1.191 +
1.192 + /* Resolve the column names in all the expressions of the
1.193 + ** of the UPDATE statement. Also find the column index
1.194 + ** for each column to be updated in the pChanges array. For each
1.195 + ** column to be updated, make sure we have authorization to change
1.196 + ** that column.
1.197 + */
1.198 + chngRowid = 0;
1.199 + for(i=0; i<pChanges->nExpr; i++){
1.200 + if( sqlite3ExprResolveNames(&sNC, pChanges->a[i].pExpr) ){
1.201 + goto update_cleanup;
1.202 + }
1.203 + for(j=0; j<pTab->nCol; j++){
1.204 + if( sqlite3StrICmp(pTab->aCol[j].zName, pChanges->a[i].zName)==0 ){
1.205 + if( j==pTab->iPKey ){
1.206 + chngRowid = 1;
1.207 + pRowidExpr = pChanges->a[i].pExpr;
1.208 + }
1.209 + aXRef[j] = i;
1.210 + break;
1.211 + }
1.212 + }
1.213 + if( j>=pTab->nCol ){
1.214 + if( sqlite3IsRowid(pChanges->a[i].zName) ){
1.215 + chngRowid = 1;
1.216 + pRowidExpr = pChanges->a[i].pExpr;
1.217 + }else{
1.218 + sqlite3ErrorMsg(pParse, "no such column: %s", pChanges->a[i].zName);
1.219 + goto update_cleanup;
1.220 + }
1.221 + }
1.222 +#ifndef SQLITE_OMIT_AUTHORIZATION
1.223 + {
1.224 + int rc;
1.225 + rc = sqlite3AuthCheck(pParse, SQLITE_UPDATE, pTab->zName,
1.226 + pTab->aCol[j].zName, db->aDb[iDb].zName);
1.227 + if( rc==SQLITE_DENY ){
1.228 + goto update_cleanup;
1.229 + }else if( rc==SQLITE_IGNORE ){
1.230 + aXRef[j] = -1;
1.231 + }
1.232 + }
1.233 +#endif
1.234 + }
1.235 +
1.236 + /* Allocate memory for the array aRegIdx[]. There is one entry in the
1.237 + ** array for each index associated with table being updated. Fill in
1.238 + ** the value with a register number for indices that are to be used
1.239 + ** and with zero for unused indices.
1.240 + */
1.241 + for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){}
1.242 + if( nIdx>0 ){
1.243 + aRegIdx = sqlite3DbMallocRaw(db, sizeof(Index*) * nIdx );
1.244 + if( aRegIdx==0 ) goto update_cleanup;
1.245 + }
1.246 + for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
1.247 + int reg;
1.248 + if( chngRowid ){
1.249 + reg = ++pParse->nMem;
1.250 + }else{
1.251 + reg = 0;
1.252 + for(i=0; i<pIdx->nColumn; i++){
1.253 + if( aXRef[pIdx->aiColumn[i]]>=0 ){
1.254 + reg = ++pParse->nMem;
1.255 + break;
1.256 + }
1.257 + }
1.258 + }
1.259 + aRegIdx[j] = reg;
1.260 + }
1.261 +
1.262 + /* Allocate a block of register used to store the change record
1.263 + ** sent to sqlite3GenerateConstraintChecks(). There are either
1.264 + ** one or two registers for holding the rowid. One rowid register
1.265 + ** is used if chngRowid is false and two are used if chngRowid is
1.266 + ** true. Following these are pTab->nCol register holding column
1.267 + ** data.
1.268 + */
1.269 + regOldRowid = regNewRowid = pParse->nMem + 1;
1.270 + pParse->nMem += pTab->nCol + 1;
1.271 + if( chngRowid ){
1.272 + regNewRowid++;
1.273 + pParse->nMem++;
1.274 + }
1.275 + regData = regNewRowid+1;
1.276 +
1.277 +
1.278 + /* Begin generating code.
1.279 + */
1.280 + v = sqlite3GetVdbe(pParse);
1.281 + if( v==0 ) goto update_cleanup;
1.282 + if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
1.283 + sqlite3BeginWriteOperation(pParse, 1, iDb);
1.284 +
1.285 +#ifndef SQLITE_OMIT_VIRTUALTABLE
1.286 + /* Virtual tables must be handled separately */
1.287 + if( IsVirtual(pTab) ){
1.288 + updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
1.289 + pWhere);
1.290 + pWhere = 0;
1.291 + pTabList = 0;
1.292 + goto update_cleanup;
1.293 + }
1.294 +#endif
1.295 +
1.296 + /* Start the view context
1.297 + */
1.298 + if( isView ){
1.299 + sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
1.300 + }
1.301 +
1.302 + /* Generate the code for triggers.
1.303 + */
1.304 + if( triggers_exist ){
1.305 + int iGoto;
1.306 +
1.307 + /* Create pseudo-tables for NEW and OLD
1.308 + */
1.309 + sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol);
1.310 + sqlite3VdbeAddOp2(v, OP_OpenPseudo, oldIdx, 0);
1.311 + sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol);
1.312 + sqlite3VdbeAddOp2(v, OP_OpenPseudo, newIdx, 0);
1.313 +
1.314 + iGoto = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
1.315 + addr = sqlite3VdbeMakeLabel(v);
1.316 + iBeginBeforeTrigger = sqlite3VdbeCurrentAddr(v);
1.317 + if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_BEFORE, pTab,
1.318 + newIdx, oldIdx, onError, addr, &old_col_mask, &new_col_mask) ){
1.319 + goto update_cleanup;
1.320 + }
1.321 + iEndBeforeTrigger = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
1.322 + iBeginAfterTrigger = sqlite3VdbeCurrentAddr(v);
1.323 + if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_AFTER, pTab,
1.324 + newIdx, oldIdx, onError, addr, &old_col_mask, &new_col_mask) ){
1.325 + goto update_cleanup;
1.326 + }
1.327 + iEndAfterTrigger = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
1.328 + sqlite3VdbeJumpHere(v, iGoto);
1.329 + }
1.330 +
1.331 + /* If we are trying to update a view, realize that view into
1.332 + ** a ephemeral table.
1.333 + */
1.334 + if( isView ){
1.335 + sqlite3MaterializeView(pParse, pTab->pSelect, pWhere, iCur);
1.336 + }
1.337 +
1.338 + /* Resolve the column names in all the expressions in the
1.339 + ** WHERE clause.
1.340 + */
1.341 + if( sqlite3ExprResolveNames(&sNC, pWhere) ){
1.342 + goto update_cleanup;
1.343 + }
1.344 +
1.345 + /* Begin the database scan
1.346 + */
1.347 + sqlite3VdbeAddOp2(v, OP_Null, 0, regOldRowid);
1.348 + pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0,
1.349 + WHERE_ONEPASS_DESIRED);
1.350 + if( pWInfo==0 ) goto update_cleanup;
1.351 + okOnePass = pWInfo->okOnePass;
1.352 +
1.353 + /* Remember the rowid of every item to be updated.
1.354 + */
1.355 + sqlite3VdbeAddOp2(v, IsVirtual(pTab)?OP_VRowid:OP_Rowid, iCur, regOldRowid);
1.356 + if( !okOnePass ) sqlite3VdbeAddOp2(v, OP_FifoWrite, regOldRowid, 0);
1.357 +
1.358 + /* End the database scan loop.
1.359 + */
1.360 + sqlite3WhereEnd(pWInfo);
1.361 +
1.362 + /* Initialize the count of updated rows
1.363 + */
1.364 + if( db->flags & SQLITE_CountRows && !pParse->trigStack ){
1.365 + regRowCount = ++pParse->nMem;
1.366 + sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
1.367 + }
1.368 +
1.369 + if( !isView && !IsVirtual(pTab) ){
1.370 + /*
1.371 + ** Open every index that needs updating. Note that if any
1.372 + ** index could potentially invoke a REPLACE conflict resolution
1.373 + ** action, then we need to open all indices because we might need
1.374 + ** to be deleting some records.
1.375 + */
1.376 + if( !okOnePass ) sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenWrite);
1.377 + if( onError==OE_Replace ){
1.378 + openAll = 1;
1.379 + }else{
1.380 + openAll = 0;
1.381 + for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
1.382 + if( pIdx->onError==OE_Replace ){
1.383 + openAll = 1;
1.384 + break;
1.385 + }
1.386 + }
1.387 + }
1.388 + for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
1.389 + if( openAll || aRegIdx[i]>0 ){
1.390 + KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
1.391 + sqlite3VdbeAddOp4(v, OP_OpenWrite, iCur+i+1, pIdx->tnum, iDb,
1.392 + (char*)pKey, P4_KEYINFO_HANDOFF);
1.393 + assert( pParse->nTab>iCur+i+1 );
1.394 + }
1.395 + }
1.396 + }
1.397 +
1.398 + /* Jump back to this point if a trigger encounters an IGNORE constraint. */
1.399 + if( triggers_exist ){
1.400 + sqlite3VdbeResolveLabel(v, addr);
1.401 + }
1.402 +
1.403 + /* Top of the update loop */
1.404 + if( okOnePass ){
1.405 + int a1 = sqlite3VdbeAddOp1(v, OP_NotNull, regOldRowid);
1.406 + addr = sqlite3VdbeAddOp0(v, OP_Goto);
1.407 + sqlite3VdbeJumpHere(v, a1);
1.408 + }else{
1.409 + addr = sqlite3VdbeAddOp2(v, OP_FifoRead, regOldRowid, 0);
1.410 + }
1.411 +
1.412 + if( triggers_exist ){
1.413 + int regRowid;
1.414 + int regRow;
1.415 + int regCols;
1.416 +
1.417 + /* Make cursor iCur point to the record that is being updated.
1.418 + */
1.419 + sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);
1.420 +
1.421 + /* Generate the OLD table
1.422 + */
1.423 + regRowid = sqlite3GetTempReg(pParse);
1.424 + regRow = sqlite3GetTempReg(pParse);
1.425 + sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regRowid);
1.426 + if( !old_col_mask ){
1.427 + sqlite3VdbeAddOp2(v, OP_Null, 0, regRow);
1.428 + }else{
1.429 + sqlite3VdbeAddOp2(v, OP_RowData, iCur, regRow);
1.430 + }
1.431 + sqlite3VdbeAddOp3(v, OP_Insert, oldIdx, regRow, regRowid);
1.432 +
1.433 + /* Generate the NEW table
1.434 + */
1.435 + if( chngRowid ){
1.436 + sqlite3ExprCodeAndCache(pParse, pRowidExpr, regRowid);
1.437 + }else{
1.438 + sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regRowid);
1.439 + }
1.440 + regCols = sqlite3GetTempRange(pParse, pTab->nCol);
1.441 + for(i=0; i<pTab->nCol; i++){
1.442 + if( i==pTab->iPKey ){
1.443 + sqlite3VdbeAddOp2(v, OP_Null, 0, regCols+i);
1.444 + continue;
1.445 + }
1.446 + j = aXRef[i];
1.447 + if( new_col_mask&((u32)1<<i) || new_col_mask==0xffffffff ){
1.448 + if( j<0 ){
1.449 + sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regCols+i);
1.450 + sqlite3ColumnDefault(v, pTab, i);
1.451 + }else{
1.452 + sqlite3ExprCodeAndCache(pParse, pChanges->a[j].pExpr, regCols+i);
1.453 + }
1.454 + }else{
1.455 + sqlite3VdbeAddOp2(v, OP_Null, 0, regCols+i);
1.456 + }
1.457 + }
1.458 + sqlite3VdbeAddOp3(v, OP_MakeRecord, regCols, pTab->nCol, regRow);
1.459 + if( !isView ){
1.460 + sqlite3TableAffinityStr(v, pTab);
1.461 + sqlite3ExprCacheAffinityChange(pParse, regCols, pTab->nCol);
1.462 + }
1.463 + sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol);
1.464 + /* if( pParse->nErr ) goto update_cleanup; */
1.465 + sqlite3VdbeAddOp3(v, OP_Insert, newIdx, regRow, regRowid);
1.466 + sqlite3ReleaseTempReg(pParse, regRowid);
1.467 + sqlite3ReleaseTempReg(pParse, regRow);
1.468 +
1.469 + sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginBeforeTrigger);
1.470 + sqlite3VdbeJumpHere(v, iEndBeforeTrigger);
1.471 + }
1.472 +
1.473 + if( !isView && !IsVirtual(pTab) ){
1.474 + /* Loop over every record that needs updating. We have to load
1.475 + ** the old data for each record to be updated because some columns
1.476 + ** might not change and we will need to copy the old value.
1.477 + ** Also, the old data is needed to delete the old index entries.
1.478 + ** So make the cursor point at the old record.
1.479 + */
1.480 + sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);
1.481 +
1.482 + /* If the record number will change, push the record number as it
1.483 + ** will be after the update. (The old record number is currently
1.484 + ** on top of the stack.)
1.485 + */
1.486 + if( chngRowid ){
1.487 + sqlite3ExprCode(pParse, pRowidExpr, regNewRowid);
1.488 + sqlite3VdbeAddOp1(v, OP_MustBeInt, regNewRowid);
1.489 + }
1.490 +
1.491 + /* Compute new data for this record.
1.492 + */
1.493 + for(i=0; i<pTab->nCol; i++){
1.494 + if( i==pTab->iPKey ){
1.495 + sqlite3VdbeAddOp2(v, OP_Null, 0, regData+i);
1.496 + continue;
1.497 + }
1.498 + j = aXRef[i];
1.499 + if( j<0 ){
1.500 + sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regData+i);
1.501 + sqlite3ColumnDefault(v, pTab, i);
1.502 + }else{
1.503 + sqlite3ExprCode(pParse, pChanges->a[j].pExpr, regData+i);
1.504 + }
1.505 + }
1.506 +
1.507 + /* Do constraint checks
1.508 + */
1.509 + sqlite3GenerateConstraintChecks(pParse, pTab, iCur, regNewRowid,
1.510 + aRegIdx, chngRowid, 1,
1.511 + onError, addr);
1.512 +
1.513 + /* Delete the old indices for the current record.
1.514 + */
1.515 + j1 = sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, regOldRowid);
1.516 + sqlite3GenerateRowIndexDelete(pParse, pTab, iCur, aRegIdx);
1.517 +
1.518 + /* If changing the record number, delete the old record.
1.519 + */
1.520 + if( chngRowid ){
1.521 + sqlite3VdbeAddOp2(v, OP_Delete, iCur, 0);
1.522 + }
1.523 + sqlite3VdbeJumpHere(v, j1);
1.524 +
1.525 + /* Create the new index entries and the new record.
1.526 + */
1.527 + sqlite3CompleteInsertion(pParse, pTab, iCur, regNewRowid,
1.528 + aRegIdx, chngRowid, 1, -1, 0);
1.529 + }
1.530 +
1.531 + /* Increment the row counter
1.532 + */
1.533 + if( db->flags & SQLITE_CountRows && !pParse->trigStack){
1.534 + sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
1.535 + }
1.536 +
1.537 + /* If there are triggers, close all the cursors after each iteration
1.538 + ** through the loop. The fire the after triggers.
1.539 + */
1.540 + if( triggers_exist ){
1.541 + sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginAfterTrigger);
1.542 + sqlite3VdbeJumpHere(v, iEndAfterTrigger);
1.543 + }
1.544 +
1.545 + /* Repeat the above with the next record to be updated, until
1.546 + ** all record selected by the WHERE clause have been updated.
1.547 + */
1.548 + sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
1.549 + sqlite3VdbeJumpHere(v, addr);
1.550 +
1.551 + /* Close all tables */
1.552 + for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
1.553 + if( openAll || aRegIdx[i]>0 ){
1.554 + sqlite3VdbeAddOp2(v, OP_Close, iCur+i+1, 0);
1.555 + }
1.556 + }
1.557 + sqlite3VdbeAddOp2(v, OP_Close, iCur, 0);
1.558 + if( triggers_exist ){
1.559 + sqlite3VdbeAddOp2(v, OP_Close, newIdx, 0);
1.560 + sqlite3VdbeAddOp2(v, OP_Close, oldIdx, 0);
1.561 + }
1.562 +
1.563 + /*
1.564 + ** Return the number of rows that were changed. If this routine is
1.565 + ** generating code because of a call to sqlite3NestedParse(), do not
1.566 + ** invoke the callback function.
1.567 + */
1.568 + if( db->flags & SQLITE_CountRows && !pParse->trigStack && pParse->nested==0 ){
1.569 + sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
1.570 + sqlite3VdbeSetNumCols(v, 1);
1.571 + sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows updated", P4_STATIC);
1.572 + }
1.573 +
1.574 +update_cleanup:
1.575 + sqlite3AuthContextPop(&sContext);
1.576 + sqlite3DbFree(db, aRegIdx);
1.577 + sqlite3DbFree(db, aXRef);
1.578 + sqlite3SrcListDelete(db, pTabList);
1.579 + sqlite3ExprListDelete(db, pChanges);
1.580 + sqlite3ExprDelete(db, pWhere);
1.581 + return;
1.582 +}
1.583 +
1.584 +#ifndef SQLITE_OMIT_VIRTUALTABLE
1.585 +/*
1.586 +** Generate code for an UPDATE of a virtual table.
1.587 +**
1.588 +** The strategy is that we create an ephemerial table that contains
1.589 +** for each row to be changed:
1.590 +**
1.591 +** (A) The original rowid of that row.
1.592 +** (B) The revised rowid for the row. (note1)
1.593 +** (C) The content of every column in the row.
1.594 +**
1.595 +** Then we loop over this ephemeral table and for each row in
1.596 +** the ephermeral table call VUpdate.
1.597 +**
1.598 +** When finished, drop the ephemeral table.
1.599 +**
1.600 +** (note1) Actually, if we know in advance that (A) is always the same
1.601 +** as (B) we only store (A), then duplicate (A) when pulling
1.602 +** it out of the ephemeral table before calling VUpdate.
1.603 +*/
1.604 +static void updateVirtualTable(
1.605 + Parse *pParse, /* The parsing context */
1.606 + SrcList *pSrc, /* The virtual table to be modified */
1.607 + Table *pTab, /* The virtual table */
1.608 + ExprList *pChanges, /* The columns to change in the UPDATE statement */
1.609 + Expr *pRowid, /* Expression used to recompute the rowid */
1.610 + int *aXRef, /* Mapping from columns of pTab to entries in pChanges */
1.611 + Expr *pWhere /* WHERE clause of the UPDATE statement */
1.612 +){
1.613 + Vdbe *v = pParse->pVdbe; /* Virtual machine under construction */
1.614 + ExprList *pEList = 0; /* The result set of the SELECT statement */
1.615 + Select *pSelect = 0; /* The SELECT statement */
1.616 + Expr *pExpr; /* Temporary expression */
1.617 + int ephemTab; /* Table holding the result of the SELECT */
1.618 + int i; /* Loop counter */
1.619 + int addr; /* Address of top of loop */
1.620 + int iReg; /* First register in set passed to OP_VUpdate */
1.621 + sqlite3 *db = pParse->db; /* Database connection */
1.622 + const char *pVtab = (const char*)pTab->pVtab;
1.623 + SelectDest dest;
1.624 +
1.625 + /* Construct the SELECT statement that will find the new values for
1.626 + ** all updated rows.
1.627 + */
1.628 + pEList = sqlite3ExprListAppend(pParse, 0,
1.629 + sqlite3CreateIdExpr(pParse, "_rowid_"), 0);
1.630 + if( pRowid ){
1.631 + pEList = sqlite3ExprListAppend(pParse, pEList,
1.632 + sqlite3ExprDup(db, pRowid), 0);
1.633 + }
1.634 + assert( pTab->iPKey<0 );
1.635 + for(i=0; i<pTab->nCol; i++){
1.636 + if( aXRef[i]>=0 ){
1.637 + pExpr = sqlite3ExprDup(db, pChanges->a[aXRef[i]].pExpr);
1.638 + }else{
1.639 + pExpr = sqlite3CreateIdExpr(pParse, pTab->aCol[i].zName);
1.640 + }
1.641 + pEList = sqlite3ExprListAppend(pParse, pEList, pExpr, 0);
1.642 + }
1.643 + pSelect = sqlite3SelectNew(pParse, pEList, pSrc, pWhere, 0, 0, 0, 0, 0, 0);
1.644 +
1.645 + /* Create the ephemeral table into which the update results will
1.646 + ** be stored.
1.647 + */
1.648 + assert( v );
1.649 + ephemTab = pParse->nTab++;
1.650 + sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, pTab->nCol+1+(pRowid!=0));
1.651 +
1.652 + /* fill the ephemeral table
1.653 + */
1.654 + sqlite3SelectDestInit(&dest, SRT_Table, ephemTab);
1.655 + sqlite3Select(pParse, pSelect, &dest, 0, 0, 0);
1.656 +
1.657 + /* Generate code to scan the ephemeral table and call VUpdate. */
1.658 + iReg = ++pParse->nMem;
1.659 + pParse->nMem += pTab->nCol+1;
1.660 + sqlite3VdbeAddOp2(v, OP_Rewind, ephemTab, 0);
1.661 + addr = sqlite3VdbeCurrentAddr(v);
1.662 + sqlite3VdbeAddOp3(v, OP_Column, ephemTab, 0, iReg);
1.663 + sqlite3VdbeAddOp3(v, OP_Column, ephemTab, (pRowid?1:0), iReg+1);
1.664 + for(i=0; i<pTab->nCol; i++){
1.665 + sqlite3VdbeAddOp3(v, OP_Column, ephemTab, i+1+(pRowid!=0), iReg+2+i);
1.666 + }
1.667 + sqlite3VtabMakeWritable(pParse, pTab);
1.668 + sqlite3VdbeAddOp4(v, OP_VUpdate, 0, pTab->nCol+2, iReg, pVtab, P4_VTAB);
1.669 + sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr);
1.670 + sqlite3VdbeJumpHere(v, addr-1);
1.671 + sqlite3VdbeAddOp2(v, OP_Close, ephemTab, 0);
1.672 +
1.673 + /* Cleanup */
1.674 + sqlite3SelectDelete(db, pSelect);
1.675 +}
1.676 +#endif /* SQLITE_OMIT_VIRTUALTABLE */
1.677 +
1.678 +/* Make sure "isView" gets undefined in case this file becomes part of
1.679 +** the amalgamation - so that subsequent files do not see isView as a
1.680 +** macro. */
1.681 +#undef isView