sl@0: /*
sl@0: ** 2001 September 15
sl@0: **
sl@0: ** The author disclaims copyright to this source code.  In place of
sl@0: ** a legal notice, here is a blessing:
sl@0: **
sl@0: **    May you do good and not evil.
sl@0: **    May you find forgiveness for yourself and forgive others.
sl@0: **    May you share freely, never taking more than you give.
sl@0: **
sl@0: *************************************************************************
sl@0: ** This file contains C code routines that are called by the parser
sl@0: ** to handle UPDATE statements.
sl@0: **
sl@0: ** $Id: update.c,v 1.185 2008/10/09 18:48:31 danielk1977 Exp $
sl@0: */
sl@0: #include "sqliteInt.h"
sl@0: 
sl@0: #ifndef SQLITE_OMIT_VIRTUALTABLE
sl@0: /* Forward declaration */
sl@0: static void updateVirtualTable(
sl@0:   Parse *pParse,       /* The parsing context */
sl@0:   SrcList *pSrc,       /* The virtual table to be modified */
sl@0:   Table *pTab,         /* The virtual table */
sl@0:   ExprList *pChanges,  /* The columns to change in the UPDATE statement */
sl@0:   Expr *pRowidExpr,    /* Expression used to recompute the rowid */
sl@0:   int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
sl@0:   Expr *pWhere         /* WHERE clause of the UPDATE statement */
sl@0: );
sl@0: #endif /* SQLITE_OMIT_VIRTUALTABLE */
sl@0: 
sl@0: /*
sl@0: ** The most recently coded instruction was an OP_Column to retrieve the
sl@0: ** i-th column of table pTab. This routine sets the P4 parameter of the 
sl@0: ** OP_Column to the default value, if any.
sl@0: **
sl@0: ** The default value of a column is specified by a DEFAULT clause in the 
sl@0: ** column definition. This was either supplied by the user when the table
sl@0: ** was created, or added later to the table definition by an ALTER TABLE
sl@0: ** command. If the latter, then the row-records in the table btree on disk
sl@0: ** may not contain a value for the column and the default value, taken
sl@0: ** from the P4 parameter of the OP_Column instruction, is returned instead.
sl@0: ** If the former, then all row-records are guaranteed to include a value
sl@0: ** for the column and the P4 value is not required.
sl@0: **
sl@0: ** Column definitions created by an ALTER TABLE command may only have 
sl@0: ** literal default values specified: a number, null or a string. (If a more
sl@0: ** complicated default expression value was provided, it is evaluated 
sl@0: ** when the ALTER TABLE is executed and one of the literal values written
sl@0: ** into the sqlite_master table.)
sl@0: **
sl@0: ** Therefore, the P4 parameter is only required if the default value for
sl@0: ** the column is a literal number, string or null. The sqlite3ValueFromExpr()
sl@0: ** function is capable of transforming these types of expressions into
sl@0: ** sqlite3_value objects.
sl@0: */
sl@0: void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){
sl@0:   if( pTab && !pTab->pSelect ){
sl@0:     sqlite3_value *pValue;
sl@0:     u8 enc = ENC(sqlite3VdbeDb(v));
sl@0:     Column *pCol = &pTab->aCol[i];
sl@0:     VdbeComment((v, "%s.%s", pTab->zName, pCol->zName));
sl@0:     assert( i<pTab->nCol );
sl@0:     sqlite3ValueFromExpr(sqlite3VdbeDb(v), pCol->pDflt, enc, 
sl@0:                          pCol->affinity, &pValue);
sl@0:     if( pValue ){
sl@0:       sqlite3VdbeChangeP4(v, -1, (const char *)pValue, P4_MEM);
sl@0:     }
sl@0:   }
sl@0: }
sl@0: 
sl@0: /*
sl@0: ** Process an UPDATE statement.
sl@0: **
sl@0: **   UPDATE OR IGNORE table_wxyz SET a=b, c=d WHERE e<5 AND f NOT NULL;
sl@0: **          \_______/ \________/     \______/       \________________/
sl@0: *            onError   pTabList      pChanges             pWhere
sl@0: */
sl@0: void sqlite3Update(
sl@0:   Parse *pParse,         /* The parser context */
sl@0:   SrcList *pTabList,     /* The table in which we should change things */
sl@0:   ExprList *pChanges,    /* Things to be changed */
sl@0:   Expr *pWhere,          /* The WHERE clause.  May be null */
sl@0:   int onError            /* How to handle constraint errors */
sl@0: ){
sl@0:   int i, j;              /* Loop counters */
sl@0:   Table *pTab;           /* The table to be updated */
sl@0:   int addr = 0;          /* VDBE instruction address of the start of the loop */
sl@0:   WhereInfo *pWInfo;     /* Information about the WHERE clause */
sl@0:   Vdbe *v;               /* The virtual database engine */
sl@0:   Index *pIdx;           /* For looping over indices */
sl@0:   int nIdx;              /* Number of indices that need updating */
sl@0:   int iCur;              /* VDBE Cursor number of pTab */
sl@0:   sqlite3 *db;           /* The database structure */
sl@0:   int *aRegIdx = 0;      /* One register assigned to each index to be updated */
sl@0:   int *aXRef = 0;        /* aXRef[i] is the index in pChanges->a[] of the
sl@0:                          ** an expression for the i-th column of the table.
sl@0:                          ** aXRef[i]==-1 if the i-th column is not changed. */
sl@0:   int chngRowid;         /* True if the record number is being changed */
sl@0:   Expr *pRowidExpr = 0;  /* Expression defining the new record number */
sl@0:   int openAll = 0;       /* True if all indices need to be opened */
sl@0:   AuthContext sContext;  /* The authorization context */
sl@0:   NameContext sNC;       /* The name-context to resolve expressions in */
sl@0:   int iDb;               /* Database containing the table being updated */
sl@0:   int j1;                /* Addresses of jump instructions */
sl@0:   int okOnePass;         /* True for one-pass algorithm without the FIFO */
sl@0: 
sl@0: #ifndef SQLITE_OMIT_TRIGGER
sl@0:   int isView;                  /* Trying to update a view */
sl@0:   int triggers_exist = 0;      /* True if any row triggers exist */
sl@0: #endif
sl@0:   int iBeginAfterTrigger;      /* Address of after trigger program */
sl@0:   int iEndAfterTrigger;        /* Exit of after trigger program */
sl@0:   int iBeginBeforeTrigger;     /* Address of before trigger program */
sl@0:   int iEndBeforeTrigger;       /* Exit of before trigger program */
sl@0:   u32 old_col_mask = 0;        /* Mask of OLD.* columns in use */
sl@0:   u32 new_col_mask = 0;        /* Mask of NEW.* columns in use */
sl@0: 
sl@0:   int newIdx      = -1;  /* index of trigger "new" temp table       */
sl@0:   int oldIdx      = -1;  /* index of trigger "old" temp table       */
sl@0: 
sl@0:   /* Register Allocations */
sl@0:   int regRowCount = 0;   /* A count of rows changed */
sl@0:   int regOldRowid;       /* The old rowid */
sl@0:   int regNewRowid;       /* The new rowid */
sl@0:   int regData;           /* New data for the row */
sl@0: 
sl@0:   sContext.pParse = 0;
sl@0:   db = pParse->db;
sl@0:   if( pParse->nErr || db->mallocFailed ){
sl@0:     goto update_cleanup;
sl@0:   }
sl@0:   assert( pTabList->nSrc==1 );
sl@0: 
sl@0:   /* Locate the table which we want to update. 
sl@0:   */
sl@0:   pTab = sqlite3SrcListLookup(pParse, pTabList);
sl@0:   if( pTab==0 ) goto update_cleanup;
sl@0:   iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
sl@0: 
sl@0:   /* Figure out if we have any triggers and if the table being
sl@0:   ** updated is a view
sl@0:   */
sl@0: #ifndef SQLITE_OMIT_TRIGGER
sl@0:   triggers_exist = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges);
sl@0:   isView = pTab->pSelect!=0;
sl@0: #else
sl@0: # define triggers_exist 0
sl@0: # define isView 0
sl@0: #endif
sl@0: #ifdef SQLITE_OMIT_VIEW
sl@0: # undef isView
sl@0: # define isView 0
sl@0: #endif
sl@0: 
sl@0:   if( sqlite3IsReadOnly(pParse, pTab, triggers_exist) ){
sl@0:     goto update_cleanup;
sl@0:   }
sl@0:   if( sqlite3ViewGetColumnNames(pParse, pTab) ){
sl@0:     goto update_cleanup;
sl@0:   }
sl@0:   aXRef = sqlite3DbMallocRaw(db, sizeof(int) * pTab->nCol );
sl@0:   if( aXRef==0 ) goto update_cleanup;
sl@0:   for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;
sl@0: 
sl@0:   /* If there are FOR EACH ROW triggers, allocate cursors for the
sl@0:   ** special OLD and NEW tables
sl@0:   */
sl@0:   if( triggers_exist ){
sl@0:     newIdx = pParse->nTab++;
sl@0:     oldIdx = pParse->nTab++;
sl@0:   }
sl@0: 
sl@0:   /* Allocate a cursors for the main database table and for all indices.
sl@0:   ** The index cursors might not be used, but if they are used they
sl@0:   ** need to occur right after the database cursor.  So go ahead and
sl@0:   ** allocate enough space, just in case.
sl@0:   */
sl@0:   pTabList->a[0].iCursor = iCur = pParse->nTab++;
sl@0:   for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
sl@0:     pParse->nTab++;
sl@0:   }
sl@0: 
sl@0:   /* Initialize the name-context */
sl@0:   memset(&sNC, 0, sizeof(sNC));
sl@0:   sNC.pParse = pParse;
sl@0:   sNC.pSrcList = pTabList;
sl@0: 
sl@0:   /* Resolve the column names in all the expressions of the
sl@0:   ** of the UPDATE statement.  Also find the column index
sl@0:   ** for each column to be updated in the pChanges array.  For each
sl@0:   ** column to be updated, make sure we have authorization to change
sl@0:   ** that column.
sl@0:   */
sl@0:   chngRowid = 0;
sl@0:   for(i=0; i<pChanges->nExpr; i++){
sl@0:     if( sqlite3ResolveExprNames(&sNC, pChanges->a[i].pExpr) ){
sl@0:       goto update_cleanup;
sl@0:     }
sl@0:     for(j=0; j<pTab->nCol; j++){
sl@0:       if( sqlite3StrICmp(pTab->aCol[j].zName, pChanges->a[i].zName)==0 ){
sl@0:         if( j==pTab->iPKey ){
sl@0:           chngRowid = 1;
sl@0:           pRowidExpr = pChanges->a[i].pExpr;
sl@0:         }
sl@0:         aXRef[j] = i;
sl@0:         break;
sl@0:       }
sl@0:     }
sl@0:     if( j>=pTab->nCol ){
sl@0:       if( sqlite3IsRowid(pChanges->a[i].zName) ){
sl@0:         chngRowid = 1;
sl@0:         pRowidExpr = pChanges->a[i].pExpr;
sl@0:       }else{
sl@0:         sqlite3ErrorMsg(pParse, "no such column: %s", pChanges->a[i].zName);
sl@0:         goto update_cleanup;
sl@0:       }
sl@0:     }
sl@0: #ifndef SQLITE_OMIT_AUTHORIZATION
sl@0:     {
sl@0:       int rc;
sl@0:       rc = sqlite3AuthCheck(pParse, SQLITE_UPDATE, pTab->zName,
sl@0:                            pTab->aCol[j].zName, db->aDb[iDb].zName);
sl@0:       if( rc==SQLITE_DENY ){
sl@0:         goto update_cleanup;
sl@0:       }else if( rc==SQLITE_IGNORE ){
sl@0:         aXRef[j] = -1;
sl@0:       }
sl@0:     }
sl@0: #endif
sl@0:   }
sl@0: 
sl@0:   /* Allocate memory for the array aRegIdx[].  There is one entry in the
sl@0:   ** array for each index associated with table being updated.  Fill in
sl@0:   ** the value with a register number for indices that are to be used
sl@0:   ** and with zero for unused indices.
sl@0:   */
sl@0:   for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){}
sl@0:   if( nIdx>0 ){
sl@0:     aRegIdx = sqlite3DbMallocRaw(db, sizeof(Index*) * nIdx );
sl@0:     if( aRegIdx==0 ) goto update_cleanup;
sl@0:   }
sl@0:   for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
sl@0:     int reg;
sl@0:     if( chngRowid ){
sl@0:       reg = ++pParse->nMem;
sl@0:     }else{
sl@0:       reg = 0;
sl@0:       for(i=0; i<pIdx->nColumn; i++){
sl@0:         if( aXRef[pIdx->aiColumn[i]]>=0 ){
sl@0:           reg = ++pParse->nMem;
sl@0:           break;
sl@0:         }
sl@0:       }
sl@0:     }
sl@0:     aRegIdx[j] = reg;
sl@0:   }
sl@0: 
sl@0:   /* Allocate a block of register used to store the change record
sl@0:   ** sent to sqlite3GenerateConstraintChecks().  There are either
sl@0:   ** one or two registers for holding the rowid.  One rowid register
sl@0:   ** is used if chngRowid is false and two are used if chngRowid is
sl@0:   ** true.  Following these are pTab->nCol register holding column
sl@0:   ** data.
sl@0:   */
sl@0:   regOldRowid = regNewRowid = pParse->nMem + 1;
sl@0:   pParse->nMem += pTab->nCol + 1;
sl@0:   if( chngRowid ){
sl@0:     regNewRowid++;
sl@0:     pParse->nMem++;
sl@0:   }
sl@0:   regData = regNewRowid+1;
sl@0:  
sl@0: 
sl@0:   /* Begin generating code.
sl@0:   */
sl@0:   v = sqlite3GetVdbe(pParse);
sl@0:   if( v==0 ) goto update_cleanup;
sl@0:   if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
sl@0:   sqlite3BeginWriteOperation(pParse, 1, iDb);
sl@0: 
sl@0: #ifndef SQLITE_OMIT_VIRTUALTABLE
sl@0:   /* Virtual tables must be handled separately */
sl@0:   if( IsVirtual(pTab) ){
sl@0:     updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
sl@0:                        pWhere);
sl@0:     pWhere = 0;
sl@0:     pTabList = 0;
sl@0:     goto update_cleanup;
sl@0:   }
sl@0: #endif
sl@0: 
sl@0:   /* Start the view context
sl@0:   */
sl@0:   if( isView ){
sl@0:     sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
sl@0:   }
sl@0: 
sl@0:   /* Generate the code for triggers.
sl@0:   */
sl@0:   if( triggers_exist ){
sl@0:     int iGoto;
sl@0: 
sl@0:     /* Create pseudo-tables for NEW and OLD
sl@0:     */
sl@0:     sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol);
sl@0:     sqlite3VdbeAddOp2(v, OP_OpenPseudo, oldIdx, 0);
sl@0:     sqlite3VdbeAddOp2(v, OP_SetNumColumns, 0, pTab->nCol);
sl@0:     sqlite3VdbeAddOp2(v, OP_OpenPseudo, newIdx, 0);
sl@0: 
sl@0:     iGoto = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
sl@0:     addr = sqlite3VdbeMakeLabel(v);
sl@0:     iBeginBeforeTrigger = sqlite3VdbeCurrentAddr(v);
sl@0:     if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_BEFORE, pTab,
sl@0:           newIdx, oldIdx, onError, addr, &old_col_mask, &new_col_mask) ){
sl@0:       goto update_cleanup;
sl@0:     }
sl@0:     iEndBeforeTrigger = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
sl@0:     iBeginAfterTrigger = sqlite3VdbeCurrentAddr(v);
sl@0:     if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_AFTER, pTab, 
sl@0:           newIdx, oldIdx, onError, addr, &old_col_mask, &new_col_mask) ){
sl@0:       goto update_cleanup;
sl@0:     }
sl@0:     iEndAfterTrigger = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
sl@0:     sqlite3VdbeJumpHere(v, iGoto);
sl@0:   }
sl@0: 
sl@0:   /* If we are trying to update a view, realize that view into
sl@0:   ** a ephemeral table.
sl@0:   */
sl@0: #if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
sl@0:   if( isView ){
sl@0:     sqlite3MaterializeView(pParse, pTab, pWhere, iCur);
sl@0:   }
sl@0: #endif
sl@0: 
sl@0:   /* Resolve the column names in all the expressions in the
sl@0:   ** WHERE clause.
sl@0:   */
sl@0:   if( sqlite3ResolveExprNames(&sNC, pWhere) ){
sl@0:     goto update_cleanup;
sl@0:   }
sl@0: 
sl@0:   /* Begin the database scan
sl@0:   */
sl@0:   sqlite3VdbeAddOp2(v, OP_Null, 0, regOldRowid);
sl@0:   pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0,
sl@0:                              WHERE_ONEPASS_DESIRED);
sl@0:   if( pWInfo==0 ) goto update_cleanup;
sl@0:   okOnePass = pWInfo->okOnePass;
sl@0: 
sl@0:   /* Remember the rowid of every item to be updated.
sl@0:   */
sl@0:   sqlite3VdbeAddOp2(v, IsVirtual(pTab)?OP_VRowid:OP_Rowid, iCur, regOldRowid);
sl@0:   if( !okOnePass ) sqlite3VdbeAddOp2(v, OP_FifoWrite, regOldRowid, 0);
sl@0: 
sl@0:   /* End the database scan loop.
sl@0:   */
sl@0:   sqlite3WhereEnd(pWInfo);
sl@0: 
sl@0:   /* Initialize the count of updated rows
sl@0:   */
sl@0:   if( db->flags & SQLITE_CountRows && !pParse->trigStack ){
sl@0:     regRowCount = ++pParse->nMem;
sl@0:     sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
sl@0:   }
sl@0: 
sl@0:   if( !isView && !IsVirtual(pTab) ){
sl@0:     /* 
sl@0:     ** Open every index that needs updating.  Note that if any
sl@0:     ** index could potentially invoke a REPLACE conflict resolution 
sl@0:     ** action, then we need to open all indices because we might need
sl@0:     ** to be deleting some records.
sl@0:     */
sl@0:     if( !okOnePass ) sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenWrite); 
sl@0:     if( onError==OE_Replace ){
sl@0:       openAll = 1;
sl@0:     }else{
sl@0:       openAll = 0;
sl@0:       for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
sl@0:         if( pIdx->onError==OE_Replace ){
sl@0:           openAll = 1;
sl@0:           break;
sl@0:         }
sl@0:       }
sl@0:     }
sl@0:     for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
sl@0:       if( openAll || aRegIdx[i]>0 ){
sl@0:         KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
sl@0:         sqlite3VdbeAddOp4(v, OP_OpenWrite, iCur+i+1, pIdx->tnum, iDb,
sl@0:                        (char*)pKey, P4_KEYINFO_HANDOFF);
sl@0:         assert( pParse->nTab>iCur+i+1 );
sl@0:       }
sl@0:     }
sl@0:   }
sl@0:   
sl@0:   /* Jump back to this point if a trigger encounters an IGNORE constraint. */
sl@0:   if( triggers_exist ){
sl@0:     sqlite3VdbeResolveLabel(v, addr);
sl@0:   }
sl@0: 
sl@0:   /* Top of the update loop */
sl@0:   if( okOnePass ){
sl@0:     int a1 = sqlite3VdbeAddOp1(v, OP_NotNull, regOldRowid);
sl@0:     addr = sqlite3VdbeAddOp0(v, OP_Goto);
sl@0:     sqlite3VdbeJumpHere(v, a1);
sl@0:   }else{
sl@0:     addr = sqlite3VdbeAddOp2(v, OP_FifoRead, regOldRowid, 0);
sl@0:   }
sl@0: 
sl@0:   if( triggers_exist ){
sl@0:     int regRowid;
sl@0:     int regRow;
sl@0:     int regCols;
sl@0: 
sl@0:     /* Make cursor iCur point to the record that is being updated.
sl@0:     */
sl@0:     sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);
sl@0: 
sl@0:     /* Generate the OLD table
sl@0:     */
sl@0:     regRowid = sqlite3GetTempReg(pParse);
sl@0:     regRow = sqlite3GetTempReg(pParse);
sl@0:     sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regRowid);
sl@0:     if( !old_col_mask ){
sl@0:       sqlite3VdbeAddOp2(v, OP_Null, 0, regRow);
sl@0:     }else{
sl@0:       sqlite3VdbeAddOp2(v, OP_RowData, iCur, regRow);
sl@0:     }
sl@0:     sqlite3VdbeAddOp3(v, OP_Insert, oldIdx, regRow, regRowid);
sl@0: 
sl@0:     /* Generate the NEW table
sl@0:     */
sl@0:     if( chngRowid ){
sl@0:       sqlite3ExprCodeAndCache(pParse, pRowidExpr, regRowid);
sl@0:       sqlite3VdbeAddOp1(v, OP_MustBeInt, regRowid);
sl@0:     }else{
sl@0:       sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regRowid);
sl@0:     }
sl@0:     regCols = sqlite3GetTempRange(pParse, pTab->nCol);
sl@0:     for(i=0; i<pTab->nCol; i++){
sl@0:       if( i==pTab->iPKey ){
sl@0:         sqlite3VdbeAddOp2(v, OP_Null, 0, regCols+i);
sl@0:         continue;
sl@0:       }
sl@0:       j = aXRef[i];
sl@0:       if( new_col_mask&((u32)1<<i) || new_col_mask==0xffffffff ){
sl@0:         if( j<0 ){
sl@0:           sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regCols+i);
sl@0:           sqlite3ColumnDefault(v, pTab, i);
sl@0:         }else{
sl@0:           sqlite3ExprCodeAndCache(pParse, pChanges->a[j].pExpr, regCols+i);
sl@0:         }
sl@0:       }else{
sl@0:         sqlite3VdbeAddOp2(v, OP_Null, 0, regCols+i);
sl@0:       }
sl@0:     }
sl@0:     sqlite3VdbeAddOp3(v, OP_MakeRecord, regCols, pTab->nCol, regRow);
sl@0:     if( !isView ){
sl@0:       sqlite3TableAffinityStr(v, pTab);
sl@0:       sqlite3ExprCacheAffinityChange(pParse, regCols, pTab->nCol);
sl@0:     }
sl@0:     sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol);
sl@0:     /* if( pParse->nErr ) goto update_cleanup; */
sl@0:     sqlite3VdbeAddOp3(v, OP_Insert, newIdx, regRow, regRowid);
sl@0:     sqlite3ReleaseTempReg(pParse, regRowid);
sl@0:     sqlite3ReleaseTempReg(pParse, regRow);
sl@0: 
sl@0:     sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginBeforeTrigger);
sl@0:     sqlite3VdbeJumpHere(v, iEndBeforeTrigger);
sl@0:   }
sl@0: 
sl@0:   if( !isView && !IsVirtual(pTab) ){
sl@0:     /* Loop over every record that needs updating.  We have to load
sl@0:     ** the old data for each record to be updated because some columns
sl@0:     ** might not change and we will need to copy the old value.
sl@0:     ** Also, the old data is needed to delete the old index entries.
sl@0:     ** So make the cursor point at the old record.
sl@0:     */
sl@0:     sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);
sl@0: 
sl@0:     /* If the record number will change, push the record number as it
sl@0:     ** will be after the update. (The old record number is currently
sl@0:     ** on top of the stack.)
sl@0:     */
sl@0:     if( chngRowid ){
sl@0:       sqlite3ExprCode(pParse, pRowidExpr, regNewRowid);
sl@0:       sqlite3VdbeAddOp1(v, OP_MustBeInt, regNewRowid);
sl@0:     }
sl@0: 
sl@0:     /* Compute new data for this record.  
sl@0:     */
sl@0:     for(i=0; i<pTab->nCol; i++){
sl@0:       if( i==pTab->iPKey ){
sl@0:         sqlite3VdbeAddOp2(v, OP_Null, 0, regData+i);
sl@0:         continue;
sl@0:       }
sl@0:       j = aXRef[i];
sl@0:       if( j<0 ){
sl@0:         sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regData+i);
sl@0:         sqlite3ColumnDefault(v, pTab, i);
sl@0:       }else{
sl@0:         sqlite3ExprCode(pParse, pChanges->a[j].pExpr, regData+i);
sl@0:       }
sl@0:     }
sl@0: 
sl@0:     /* Do constraint checks
sl@0:     */
sl@0:     sqlite3GenerateConstraintChecks(pParse, pTab, iCur, regNewRowid,
sl@0:                                     aRegIdx, chngRowid, 1,
sl@0:                                     onError, addr);
sl@0: 
sl@0:     /* Delete the old indices for the current record.
sl@0:     */
sl@0:     j1 = sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, regOldRowid);
sl@0:     sqlite3GenerateRowIndexDelete(pParse, pTab, iCur, aRegIdx);
sl@0: 
sl@0:     /* If changing the record number, delete the old record.
sl@0:     */
sl@0:     if( chngRowid ){
sl@0:       sqlite3VdbeAddOp2(v, OP_Delete, iCur, 0);
sl@0:     }
sl@0:     sqlite3VdbeJumpHere(v, j1);
sl@0: 
sl@0:     /* Create the new index entries and the new record.
sl@0:     */
sl@0:     sqlite3CompleteInsertion(pParse, pTab, iCur, regNewRowid, 
sl@0:                              aRegIdx, chngRowid, 1, -1, 0);
sl@0:   }
sl@0: 
sl@0:   /* Increment the row counter 
sl@0:   */
sl@0:   if( db->flags & SQLITE_CountRows && !pParse->trigStack){
sl@0:     sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
sl@0:   }
sl@0: 
sl@0:   /* If there are triggers, close all the cursors after each iteration
sl@0:   ** through the loop.  The fire the after triggers.
sl@0:   */
sl@0:   if( triggers_exist ){
sl@0:     sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginAfterTrigger);
sl@0:     sqlite3VdbeJumpHere(v, iEndAfterTrigger);
sl@0:   }
sl@0: 
sl@0:   /* Repeat the above with the next record to be updated, until
sl@0:   ** all record selected by the WHERE clause have been updated.
sl@0:   */
sl@0:   sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
sl@0:   sqlite3VdbeJumpHere(v, addr);
sl@0: 
sl@0:   /* Close all tables */
sl@0:   for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
sl@0:     if( openAll || aRegIdx[i]>0 ){
sl@0:       sqlite3VdbeAddOp2(v, OP_Close, iCur+i+1, 0);
sl@0:     }
sl@0:   }
sl@0:   sqlite3VdbeAddOp2(v, OP_Close, iCur, 0);
sl@0:   if( triggers_exist ){
sl@0:     sqlite3VdbeAddOp2(v, OP_Close, newIdx, 0);
sl@0:     sqlite3VdbeAddOp2(v, OP_Close, oldIdx, 0);
sl@0:   }
sl@0: 
sl@0:   /*
sl@0:   ** Return the number of rows that were changed. If this routine is 
sl@0:   ** generating code because of a call to sqlite3NestedParse(), do not
sl@0:   ** invoke the callback function.
sl@0:   */
sl@0:   if( db->flags & SQLITE_CountRows && !pParse->trigStack && pParse->nested==0 ){
sl@0:     sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
sl@0:     sqlite3VdbeSetNumCols(v, 1);
sl@0:     sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows updated", P4_STATIC);
sl@0:   }
sl@0: 
sl@0: update_cleanup:
sl@0:   sqlite3AuthContextPop(&sContext);
sl@0:   sqlite3DbFree(db, aRegIdx);
sl@0:   sqlite3DbFree(db, aXRef);
sl@0:   sqlite3SrcListDelete(db, pTabList);
sl@0:   sqlite3ExprListDelete(db, pChanges);
sl@0:   sqlite3ExprDelete(db, pWhere);
sl@0:   return;
sl@0: }
sl@0: 
sl@0: #ifndef SQLITE_OMIT_VIRTUALTABLE
sl@0: /*
sl@0: ** Generate code for an UPDATE of a virtual table.
sl@0: **
sl@0: ** The strategy is that we create an ephemerial table that contains
sl@0: ** for each row to be changed:
sl@0: **
sl@0: **   (A)  The original rowid of that row.
sl@0: **   (B)  The revised rowid for the row. (note1)
sl@0: **   (C)  The content of every column in the row.
sl@0: **
sl@0: ** Then we loop over this ephemeral table and for each row in
sl@0: ** the ephermeral table call VUpdate.
sl@0: **
sl@0: ** When finished, drop the ephemeral table.
sl@0: **
sl@0: ** (note1) Actually, if we know in advance that (A) is always the same
sl@0: ** as (B) we only store (A), then duplicate (A) when pulling
sl@0: ** it out of the ephemeral table before calling VUpdate.
sl@0: */
sl@0: static void updateVirtualTable(
sl@0:   Parse *pParse,       /* The parsing context */
sl@0:   SrcList *pSrc,       /* The virtual table to be modified */
sl@0:   Table *pTab,         /* The virtual table */
sl@0:   ExprList *pChanges,  /* The columns to change in the UPDATE statement */
sl@0:   Expr *pRowid,        /* Expression used to recompute the rowid */
sl@0:   int *aXRef,          /* Mapping from columns of pTab to entries in pChanges */
sl@0:   Expr *pWhere         /* WHERE clause of the UPDATE statement */
sl@0: ){
sl@0:   Vdbe *v = pParse->pVdbe;  /* Virtual machine under construction */
sl@0:   ExprList *pEList = 0;     /* The result set of the SELECT statement */
sl@0:   Select *pSelect = 0;      /* The SELECT statement */
sl@0:   Expr *pExpr;              /* Temporary expression */
sl@0:   int ephemTab;             /* Table holding the result of the SELECT */
sl@0:   int i;                    /* Loop counter */
sl@0:   int addr;                 /* Address of top of loop */
sl@0:   int iReg;                 /* First register in set passed to OP_VUpdate */
sl@0:   sqlite3 *db = pParse->db; /* Database connection */
sl@0:   const char *pVtab = (const char*)pTab->pVtab;
sl@0:   SelectDest dest;
sl@0: 
sl@0:   /* Construct the SELECT statement that will find the new values for
sl@0:   ** all updated rows. 
sl@0:   */
sl@0:   pEList = sqlite3ExprListAppend(pParse, 0, 
sl@0:                                  sqlite3CreateIdExpr(pParse, "_rowid_"), 0);
sl@0:   if( pRowid ){
sl@0:     pEList = sqlite3ExprListAppend(pParse, pEList,
sl@0:                                    sqlite3ExprDup(db, pRowid), 0);
sl@0:   }
sl@0:   assert( pTab->iPKey<0 );
sl@0:   for(i=0; i<pTab->nCol; i++){
sl@0:     if( aXRef[i]>=0 ){
sl@0:       pExpr = sqlite3ExprDup(db, pChanges->a[aXRef[i]].pExpr);
sl@0:     }else{
sl@0:       pExpr = sqlite3CreateIdExpr(pParse, pTab->aCol[i].zName);
sl@0:     }
sl@0:     pEList = sqlite3ExprListAppend(pParse, pEList, pExpr, 0);
sl@0:   }
sl@0:   pSelect = sqlite3SelectNew(pParse, pEList, pSrc, pWhere, 0, 0, 0, 0, 0, 0);
sl@0:   
sl@0:   /* Create the ephemeral table into which the update results will
sl@0:   ** be stored.
sl@0:   */
sl@0:   assert( v );
sl@0:   ephemTab = pParse->nTab++;
sl@0:   sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, pTab->nCol+1+(pRowid!=0));
sl@0: 
sl@0:   /* fill the ephemeral table 
sl@0:   */
sl@0:   sqlite3SelectDestInit(&dest, SRT_Table, ephemTab);
sl@0:   sqlite3Select(pParse, pSelect, &dest);
sl@0: 
sl@0:   /* Generate code to scan the ephemeral table and call VUpdate. */
sl@0:   iReg = ++pParse->nMem;
sl@0:   pParse->nMem += pTab->nCol+1;
sl@0:   sqlite3VdbeAddOp2(v, OP_Rewind, ephemTab, 0);
sl@0:   addr = sqlite3VdbeCurrentAddr(v);
sl@0:   sqlite3VdbeAddOp3(v, OP_Column,  ephemTab, 0, iReg);
sl@0:   sqlite3VdbeAddOp3(v, OP_Column, ephemTab, (pRowid?1:0), iReg+1);
sl@0:   for(i=0; i<pTab->nCol; i++){
sl@0:     sqlite3VdbeAddOp3(v, OP_Column, ephemTab, i+1+(pRowid!=0), iReg+2+i);
sl@0:   }
sl@0:   sqlite3VtabMakeWritable(pParse, pTab);
sl@0:   sqlite3VdbeAddOp4(v, OP_VUpdate, 0, pTab->nCol+2, iReg, pVtab, P4_VTAB);
sl@0:   sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr);
sl@0:   sqlite3VdbeJumpHere(v, addr-1);
sl@0:   sqlite3VdbeAddOp2(v, OP_Close, ephemTab, 0);
sl@0: 
sl@0:   /* Cleanup */
sl@0:   sqlite3SelectDelete(db, pSelect);  
sl@0: }
sl@0: #endif /* SQLITE_OMIT_VIRTUALTABLE */
sl@0: 
sl@0: /* Make sure "isView" gets undefined in case this file becomes part of
sl@0: ** the amalgamation - so that subsequent files do not see isView as a
sl@0: ** macro. */
sl@0: #undef isView