| Index: third_party/sqlite/src/update.c
|
| ===================================================================
|
| --- third_party/sqlite/src/update.c (revision 56608)
|
| +++ third_party/sqlite/src/update.c (working copy)
|
| @@ -1,609 +0,0 @@
|
| -/*
|
| -** 2001 September 15
|
| -**
|
| -** The author disclaims copyright to this source code. In place of
|
| -** a legal notice, here is a blessing:
|
| -**
|
| -** May you do good and not evil.
|
| -** May you find forgiveness for yourself and forgive others.
|
| -** May you share freely, never taking more than you give.
|
| -**
|
| -*************************************************************************
|
| -** This file contains C code routines that are called by the parser
|
| -** to handle UPDATE statements.
|
| -**
|
| -** $Id: update.c,v 1.207 2009/08/08 18:01:08 drh Exp $
|
| -*/
|
| -#include "sqliteInt.h"
|
| -
|
| -#ifndef SQLITE_OMIT_VIRTUALTABLE
|
| -/* Forward declaration */
|
| -static void updateVirtualTable(
|
| - Parse *pParse, /* The parsing context */
|
| - SrcList *pSrc, /* The virtual table to be modified */
|
| - Table *pTab, /* The virtual table */
|
| - ExprList *pChanges, /* The columns to change in the UPDATE statement */
|
| - Expr *pRowidExpr, /* Expression used to recompute the rowid */
|
| - int *aXRef, /* Mapping from columns of pTab to entries in pChanges */
|
| - Expr *pWhere /* WHERE clause of the UPDATE statement */
|
| -);
|
| -#endif /* SQLITE_OMIT_VIRTUALTABLE */
|
| -
|
| -/*
|
| -** The most recently coded instruction was an OP_Column to retrieve the
|
| -** i-th column of table pTab. This routine sets the P4 parameter of the
|
| -** OP_Column to the default value, if any.
|
| -**
|
| -** The default value of a column is specified by a DEFAULT clause in the
|
| -** column definition. This was either supplied by the user when the table
|
| -** was created, or added later to the table definition by an ALTER TABLE
|
| -** command. If the latter, then the row-records in the table btree on disk
|
| -** may not contain a value for the column and the default value, taken
|
| -** from the P4 parameter of the OP_Column instruction, is returned instead.
|
| -** If the former, then all row-records are guaranteed to include a value
|
| -** for the column and the P4 value is not required.
|
| -**
|
| -** Column definitions created by an ALTER TABLE command may only have
|
| -** literal default values specified: a number, null or a string. (If a more
|
| -** complicated default expression value was provided, it is evaluated
|
| -** when the ALTER TABLE is executed and one of the literal values written
|
| -** into the sqlite_master table.)
|
| -**
|
| -** Therefore, the P4 parameter is only required if the default value for
|
| -** the column is a literal number, string or null. The sqlite3ValueFromExpr()
|
| -** function is capable of transforming these types of expressions into
|
| -** sqlite3_value objects.
|
| -**
|
| -** If parameter iReg is not negative, code an OP_RealAffinity instruction
|
| -** on register iReg. This is used when an equivalent integer value is
|
| -** stored in place of an 8-byte floating point value in order to save
|
| -** space.
|
| -*/
|
| -void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i, int iReg){
|
| - assert( pTab!=0 );
|
| - if( !pTab->pSelect ){
|
| - sqlite3_value *pValue;
|
| - u8 enc = ENC(sqlite3VdbeDb(v));
|
| - Column *pCol = &pTab->aCol[i];
|
| - VdbeComment((v, "%s.%s", pTab->zName, pCol->zName));
|
| - assert( i<pTab->nCol );
|
| - sqlite3ValueFromExpr(sqlite3VdbeDb(v), pCol->pDflt, enc,
|
| - pCol->affinity, &pValue);
|
| - if( pValue ){
|
| - sqlite3VdbeChangeP4(v, -1, (const char *)pValue, P4_MEM);
|
| - }
|
| -#ifndef SQLITE_OMIT_FLOATING_POINT
|
| - if( iReg>=0 && pTab->aCol[i].affinity==SQLITE_AFF_REAL ){
|
| - sqlite3VdbeAddOp1(v, OP_RealAffinity, iReg);
|
| - }
|
| -#endif
|
| - }
|
| -}
|
| -
|
| -/*
|
| -** Process an UPDATE statement.
|
| -**
|
| -** UPDATE OR IGNORE table_wxyz SET a=b, c=d WHERE e<5 AND f NOT NULL;
|
| -** \_______/ \________/ \______/ \________________/
|
| -* onError pTabList pChanges pWhere
|
| -*/
|
| -void sqlite3Update(
|
| - Parse *pParse, /* The parser context */
|
| - SrcList *pTabList, /* The table in which we should change things */
|
| - ExprList *pChanges, /* Things to be changed */
|
| - Expr *pWhere, /* The WHERE clause. May be null */
|
| - int onError /* How to handle constraint errors */
|
| -){
|
| - int i, j; /* Loop counters */
|
| - Table *pTab; /* The table to be updated */
|
| - int addr = 0; /* VDBE instruction address of the start of the loop */
|
| - WhereInfo *pWInfo; /* Information about the WHERE clause */
|
| - Vdbe *v; /* The virtual database engine */
|
| - Index *pIdx; /* For looping over indices */
|
| - int nIdx; /* Number of indices that need updating */
|
| - int iCur; /* VDBE Cursor number of pTab */
|
| - sqlite3 *db; /* The database structure */
|
| - int *aRegIdx = 0; /* One register assigned to each index to be updated */
|
| - int *aXRef = 0; /* aXRef[i] is the index in pChanges->a[] of the
|
| - ** an expression for the i-th column of the table.
|
| - ** aXRef[i]==-1 if the i-th column is not changed. */
|
| - int chngRowid; /* True if the record number is being changed */
|
| - Expr *pRowidExpr = 0; /* Expression defining the new record number */
|
| - int openAll = 0; /* True if all indices need to be opened */
|
| - AuthContext sContext; /* The authorization context */
|
| - NameContext sNC; /* The name-context to resolve expressions in */
|
| - int iDb; /* Database containing the table being updated */
|
| - int j1; /* Addresses of jump instructions */
|
| - int okOnePass; /* True for one-pass algorithm without the FIFO */
|
| -
|
| -#ifndef SQLITE_OMIT_TRIGGER
|
| - int isView; /* Trying to update a view */
|
| - Trigger *pTrigger; /* List of triggers on pTab, if required */
|
| -#endif
|
| - u32 oldmask = 0; /* Mask of OLD.* columns in use */
|
| -
|
| - /* Register Allocations */
|
| - int regRowCount = 0; /* A count of rows changed */
|
| - int regOldRowid; /* The old rowid */
|
| - int regNewRowid; /* The new rowid */
|
| - int regNew;
|
| - int regOld = 0;
|
| - int regRowSet = 0; /* Rowset of rows to be updated */
|
| - int regRec; /* Register used for new table record to insert */
|
| -
|
| - memset(&sContext, 0, sizeof(sContext));
|
| - db = pParse->db;
|
| - if( pParse->nErr || db->mallocFailed ){
|
| - goto update_cleanup;
|
| - }
|
| - assert( pTabList->nSrc==1 );
|
| -
|
| - /* Locate the table which we want to update.
|
| - */
|
| - pTab = sqlite3SrcListLookup(pParse, pTabList);
|
| - if( pTab==0 ) goto update_cleanup;
|
| - iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
|
| -
|
| - /* Figure out if we have any triggers and if the table being
|
| - ** updated is a view.
|
| - */
|
| -#ifndef SQLITE_OMIT_TRIGGER
|
| - pTrigger = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges, 0);
|
| - isView = pTab->pSelect!=0;
|
| -#else
|
| -# define pTrigger 0
|
| -# define isView 0
|
| -#endif
|
| -#ifdef SQLITE_OMIT_VIEW
|
| -# undef isView
|
| -# define isView 0
|
| -#endif
|
| -
|
| - if( sqlite3ViewGetColumnNames(pParse, pTab) ){
|
| - goto update_cleanup;
|
| - }
|
| - if( sqlite3IsReadOnly(pParse, pTab, (pTrigger?1:0)) ){
|
| - goto update_cleanup;
|
| - }
|
| - aXRef = sqlite3DbMallocRaw(db, sizeof(int) * pTab->nCol );
|
| - if( aXRef==0 ) goto update_cleanup;
|
| - for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;
|
| -
|
| - /* Allocate a cursors for the main database table and for all indices.
|
| - ** The index cursors might not be used, but if they are used they
|
| - ** need to occur right after the database cursor. So go ahead and
|
| - ** allocate enough space, just in case.
|
| - */
|
| - pTabList->a[0].iCursor = iCur = pParse->nTab++;
|
| - for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
|
| - pParse->nTab++;
|
| - }
|
| -
|
| - /* Initialize the name-context */
|
| - memset(&sNC, 0, sizeof(sNC));
|
| - sNC.pParse = pParse;
|
| - sNC.pSrcList = pTabList;
|
| -
|
| - /* Resolve the column names in all the expressions of the
|
| - ** of the UPDATE statement. Also find the column index
|
| - ** for each column to be updated in the pChanges array. For each
|
| - ** column to be updated, make sure we have authorization to change
|
| - ** that column.
|
| - */
|
| - chngRowid = 0;
|
| - for(i=0; i<pChanges->nExpr; i++){
|
| - if( sqlite3ResolveExprNames(&sNC, pChanges->a[i].pExpr) ){
|
| - goto update_cleanup;
|
| - }
|
| - for(j=0; j<pTab->nCol; j++){
|
| - if( sqlite3StrICmp(pTab->aCol[j].zName, pChanges->a[i].zName)==0 ){
|
| - if( j==pTab->iPKey ){
|
| - chngRowid = 1;
|
| - pRowidExpr = pChanges->a[i].pExpr;
|
| - }
|
| - aXRef[j] = i;
|
| - break;
|
| - }
|
| - }
|
| - if( j>=pTab->nCol ){
|
| - if( sqlite3IsRowid(pChanges->a[i].zName) ){
|
| - chngRowid = 1;
|
| - pRowidExpr = pChanges->a[i].pExpr;
|
| - }else{
|
| - sqlite3ErrorMsg(pParse, "no such column: %s", pChanges->a[i].zName);
|
| - goto update_cleanup;
|
| - }
|
| - }
|
| -#ifndef SQLITE_OMIT_AUTHORIZATION
|
| - {
|
| - int rc;
|
| - rc = sqlite3AuthCheck(pParse, SQLITE_UPDATE, pTab->zName,
|
| - pTab->aCol[j].zName, db->aDb[iDb].zName);
|
| - if( rc==SQLITE_DENY ){
|
| - goto update_cleanup;
|
| - }else if( rc==SQLITE_IGNORE ){
|
| - aXRef[j] = -1;
|
| - }
|
| - }
|
| -#endif
|
| - }
|
| -
|
| - /* Allocate memory for the array aRegIdx[]. There is one entry in the
|
| - ** array for each index associated with table being updated. Fill in
|
| - ** the value with a register number for indices that are to be used
|
| - ** and with zero for unused indices.
|
| - */
|
| - for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){}
|
| - if( nIdx>0 ){
|
| - aRegIdx = sqlite3DbMallocRaw(db, sizeof(Index*) * nIdx );
|
| - if( aRegIdx==0 ) goto update_cleanup;
|
| - }
|
| - for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
|
| - int reg;
|
| - if( chngRowid ){
|
| - reg = ++pParse->nMem;
|
| - }else{
|
| - reg = 0;
|
| - for(i=0; i<pIdx->nColumn; i++){
|
| - if( aXRef[pIdx->aiColumn[i]]>=0 ){
|
| - reg = ++pParse->nMem;
|
| - break;
|
| - }
|
| - }
|
| - }
|
| - aRegIdx[j] = reg;
|
| - }
|
| -
|
| - /* Begin generating code. */
|
| - v = sqlite3GetVdbe(pParse);
|
| - if( v==0 ) goto update_cleanup;
|
| - if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
|
| - sqlite3BeginWriteOperation(pParse, 1, iDb);
|
| -
|
| -#ifndef SQLITE_OMIT_VIRTUALTABLE
|
| - /* Virtual tables must be handled separately */
|
| - if( IsVirtual(pTab) ){
|
| - updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
|
| - pWhere);
|
| - pWhere = 0;
|
| - pTabList = 0;
|
| - goto update_cleanup;
|
| - }
|
| -#endif
|
| -
|
| - /* Allocate required registers. */
|
| - regOldRowid = regNewRowid = ++pParse->nMem;
|
| - if( pTrigger ){
|
| - regOld = pParse->nMem + 1;
|
| - pParse->nMem += pTab->nCol;
|
| - }
|
| - if( chngRowid || pTrigger ){
|
| - regNewRowid = ++pParse->nMem;
|
| - }
|
| - regNew = pParse->nMem + 1;
|
| - pParse->nMem += pTab->nCol;
|
| - regRec = ++pParse->nMem;
|
| -
|
| - /* Start the view context. */
|
| - if( isView ){
|
| - sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
|
| - }
|
| -
|
| - /* If there are any triggers, set oldmask and new_col_mask. */
|
| - oldmask = sqlite3TriggerOldmask(
|
| - pParse, pTrigger, TK_UPDATE, pChanges, pTab, onError);
|
| -
|
| - /* If we are trying to update a view, realize that view into
|
| - ** a ephemeral table.
|
| - */
|
| -#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
|
| - if( isView ){
|
| - sqlite3MaterializeView(pParse, pTab, pWhere, iCur);
|
| - }
|
| -#endif
|
| -
|
| - /* Resolve the column names in all the expressions in the
|
| - ** WHERE clause.
|
| - */
|
| - if( sqlite3ResolveExprNames(&sNC, pWhere) ){
|
| - goto update_cleanup;
|
| - }
|
| -
|
| - /* Begin the database scan
|
| - */
|
| - sqlite3VdbeAddOp2(v, OP_Null, 0, regOldRowid);
|
| - pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere,0, WHERE_ONEPASS_DESIRED);
|
| - if( pWInfo==0 ) goto update_cleanup;
|
| - okOnePass = pWInfo->okOnePass;
|
| -
|
| - /* Remember the rowid of every item to be updated.
|
| - */
|
| - sqlite3VdbeAddOp2(v, OP_Rowid, iCur, regOldRowid);
|
| - if( !okOnePass ){
|
| - regRowSet = ++pParse->nMem;
|
| - sqlite3VdbeAddOp2(v, OP_RowSetAdd, regRowSet, regOldRowid);
|
| - }
|
| -
|
| - /* End the database scan loop.
|
| - */
|
| - sqlite3WhereEnd(pWInfo);
|
| -
|
| - /* Initialize the count of updated rows
|
| - */
|
| - if( (db->flags & SQLITE_CountRows) && !pParse->pTriggerTab ){
|
| - regRowCount = ++pParse->nMem;
|
| - sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
|
| - }
|
| -
|
| - if( !isView ){
|
| - /*
|
| - ** Open every index that needs updating. Note that if any
|
| - ** index could potentially invoke a REPLACE conflict resolution
|
| - ** action, then we need to open all indices because we might need
|
| - ** to be deleting some records.
|
| - */
|
| - if( !okOnePass ) sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenWrite);
|
| - if( onError==OE_Replace ){
|
| - openAll = 1;
|
| - }else{
|
| - openAll = 0;
|
| - for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
|
| - if( pIdx->onError==OE_Replace ){
|
| - openAll = 1;
|
| - break;
|
| - }
|
| - }
|
| - }
|
| - for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
|
| - if( openAll || aRegIdx[i]>0 ){
|
| - KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
|
| - sqlite3VdbeAddOp4(v, OP_OpenWrite, iCur+i+1, pIdx->tnum, iDb,
|
| - (char*)pKey, P4_KEYINFO_HANDOFF);
|
| - assert( pParse->nTab>iCur+i+1 );
|
| - }
|
| - }
|
| - }
|
| -
|
| - /* Top of the update loop */
|
| - if( okOnePass ){
|
| - int a1 = sqlite3VdbeAddOp1(v, OP_NotNull, regOldRowid);
|
| - addr = sqlite3VdbeAddOp0(v, OP_Goto);
|
| - sqlite3VdbeJumpHere(v, a1);
|
| - }else{
|
| - addr = sqlite3VdbeAddOp3(v, OP_RowSetRead, regRowSet, 0, regOldRowid);
|
| - }
|
| -
|
| - /* Make cursor iCur point to the record that is being updated. If
|
| - ** this record does not exist for some reason (deleted by a trigger,
|
| - ** for example, then jump to the next iteration of the RowSet loop. */
|
| - sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);
|
| -
|
| - /* If there are triggers on this table, populate an array of registers
|
| - ** with the required old.* column data. */
|
| - if( pTrigger ){
|
| - for(i=0; i<pTab->nCol; i++){
|
| - if( aXRef[i]<0 || oldmask==0xffffffff || (oldmask & (1<<i)) ){
|
| - sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regOld+i);
|
| - sqlite3ColumnDefault(v, pTab, i, regOld+i);
|
| - }else{
|
| - sqlite3VdbeAddOp2(v, OP_Null, 0, regOld+i);
|
| - }
|
| - }
|
| - }
|
| -
|
| - /* If the record number will change, set register regNewRowid to
|
| - ** contain the new value. If the record number is not being modified,
|
| - ** then regNewRowid is the same register as regOldRowid, which is
|
| - ** already populated. */
|
| - assert( chngRowid || pTrigger || regOldRowid==regNewRowid );
|
| - if( chngRowid ){
|
| - sqlite3ExprCode(pParse, pRowidExpr, regNewRowid);
|
| - sqlite3VdbeAddOp1(v, OP_MustBeInt, regNewRowid);
|
| - }else if( pTrigger ){
|
| - sqlite3VdbeAddOp2(v, OP_Copy, regOldRowid, regNewRowid);
|
| - }
|
| -
|
| - /* Populate the array of registers beginning at regNew with the new
|
| - ** row data. This array is used to check constaints, create the new
|
| - ** table and index records, and as the values for any new.* references
|
| - ** made by triggers. */
|
| - for(i=0; i<pTab->nCol; i++){
|
| - if( i==pTab->iPKey ){
|
| - sqlite3VdbeAddOp2(v, OP_Null, 0, regNew+i);
|
| - }else{
|
| - j = aXRef[i];
|
| - if( j<0 ){
|
| - sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regNew+i);
|
| - sqlite3ColumnDefault(v, pTab, i, regNew+i);
|
| - }else{
|
| - sqlite3ExprCode(pParse, pChanges->a[j].pExpr, regNew+i);
|
| - }
|
| - }
|
| - }
|
| -
|
| - /* Fire any BEFORE UPDATE triggers. This happens before constraints are
|
| - ** verified. One could argue that this is wrong. */
|
| - if( pTrigger ){
|
| - sqlite3VdbeAddOp2(v, OP_Affinity, regNew, pTab->nCol);
|
| - sqlite3TableAffinityStr(v, pTab);
|
| - sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges,
|
| - TRIGGER_BEFORE, pTab, -1, regOldRowid, onError, addr);
|
| -
|
| - /* The row-trigger may have deleted the row being updated. In this
|
| - ** case, jump to the next row. No updates or AFTER triggers are
|
| - ** required. This behaviour - what happens when the row being updated
|
| - ** is deleted or renamed by a BEFORE trigger - is left undefined in the
|
| - ** documentation. */
|
| - sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);
|
| - }
|
| -
|
| - if( !isView ){
|
| -
|
| - /* Do constraint checks. */
|
| - sqlite3GenerateConstraintChecks(pParse, pTab, iCur, regNewRowid,
|
| - aRegIdx, (chngRowid?regOldRowid:0), 1, onError, addr, 0);
|
| -
|
| - /* Delete the index entries associated with the current record. */
|
| - j1 = sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, regOldRowid);
|
| - sqlite3GenerateRowIndexDelete(pParse, pTab, iCur, aRegIdx);
|
| -
|
| - /* If changing the record number, delete the old record. */
|
| - if( chngRowid ){
|
| - sqlite3VdbeAddOp2(v, OP_Delete, iCur, 0);
|
| - }
|
| - sqlite3VdbeJumpHere(v, j1);
|
| -
|
| - /* Insert the new index entries and the new record. */
|
| - sqlite3CompleteInsertion(pParse, pTab, iCur, regNewRowid, aRegIdx, 1, 0, 0);
|
| - }
|
| -
|
| - /* Increment the row counter
|
| - */
|
| - if( (db->flags & SQLITE_CountRows) && !pParse->pTriggerTab){
|
| - sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
|
| - }
|
| -
|
| - sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges,
|
| - TRIGGER_AFTER, pTab, -1, regOldRowid, onError, addr);
|
| -
|
| - /* Repeat the above with the next record to be updated, until
|
| - ** all record selected by the WHERE clause have been updated.
|
| - */
|
| - sqlite3VdbeAddOp2(v, OP_Goto, 0, addr);
|
| - sqlite3VdbeJumpHere(v, addr);
|
| -
|
| - /* Close all tables */
|
| - for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
|
| - if( openAll || aRegIdx[i]>0 ){
|
| - sqlite3VdbeAddOp2(v, OP_Close, iCur+i+1, 0);
|
| - }
|
| - }
|
| - sqlite3VdbeAddOp2(v, OP_Close, iCur, 0);
|
| -
|
| - /* Update the sqlite_sequence table by storing the content of the
|
| - ** maximum rowid counter values recorded while inserting into
|
| - ** autoincrement tables.
|
| - */
|
| - if( pParse->nested==0 && pParse->pTriggerTab==0 ){
|
| - sqlite3AutoincrementEnd(pParse);
|
| - }
|
| -
|
| - /*
|
| - ** Return the number of rows that were changed. If this routine is
|
| - ** generating code because of a call to sqlite3NestedParse(), do not
|
| - ** invoke the callback function.
|
| - */
|
| - if( (db->flags&SQLITE_CountRows) && !pParse->pTriggerTab && !pParse->nested ){
|
| - sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
|
| - sqlite3VdbeSetNumCols(v, 1);
|
| - sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows updated", SQLITE_STATIC);
|
| - }
|
| -
|
| -update_cleanup:
|
| - sqlite3AuthContextPop(&sContext);
|
| - sqlite3DbFree(db, aRegIdx);
|
| - sqlite3DbFree(db, aXRef);
|
| - sqlite3SrcListDelete(db, pTabList);
|
| - sqlite3ExprListDelete(db, pChanges);
|
| - sqlite3ExprDelete(db, pWhere);
|
| - return;
|
| -}
|
| -
|
| -#ifndef SQLITE_OMIT_VIRTUALTABLE
|
| -/*
|
| -** Generate code for an UPDATE of a virtual table.
|
| -**
|
| -** The strategy is that we create an ephemerial table that contains
|
| -** for each row to be changed:
|
| -**
|
| -** (A) The original rowid of that row.
|
| -** (B) The revised rowid for the row. (note1)
|
| -** (C) The content of every column in the row.
|
| -**
|
| -** Then we loop over this ephemeral table and for each row in
|
| -** the ephermeral table call VUpdate.
|
| -**
|
| -** When finished, drop the ephemeral table.
|
| -**
|
| -** (note1) Actually, if we know in advance that (A) is always the same
|
| -** as (B) we only store (A), then duplicate (A) when pulling
|
| -** it out of the ephemeral table before calling VUpdate.
|
| -*/
|
| -static void updateVirtualTable(
|
| - Parse *pParse, /* The parsing context */
|
| - SrcList *pSrc, /* The virtual table to be modified */
|
| - Table *pTab, /* The virtual table */
|
| - ExprList *pChanges, /* The columns to change in the UPDATE statement */
|
| - Expr *pRowid, /* Expression used to recompute the rowid */
|
| - int *aXRef, /* Mapping from columns of pTab to entries in pChanges */
|
| - Expr *pWhere /* WHERE clause of the UPDATE statement */
|
| -){
|
| - Vdbe *v = pParse->pVdbe; /* Virtual machine under construction */
|
| - ExprList *pEList = 0; /* The result set of the SELECT statement */
|
| - Select *pSelect = 0; /* The SELECT statement */
|
| - Expr *pExpr; /* Temporary expression */
|
| - int ephemTab; /* Table holding the result of the SELECT */
|
| - int i; /* Loop counter */
|
| - int addr; /* Address of top of loop */
|
| - int iReg; /* First register in set passed to OP_VUpdate */
|
| - sqlite3 *db = pParse->db; /* Database connection */
|
| - const char *pVTab = (const char*)sqlite3GetVTable(db, pTab);
|
| - SelectDest dest;
|
| -
|
| - /* Construct the SELECT statement that will find the new values for
|
| - ** all updated rows.
|
| - */
|
| - pEList = sqlite3ExprListAppend(pParse, 0,
|
| - sqlite3CreateIdExpr(pParse, "_rowid_"));
|
| - if( pRowid ){
|
| - pEList = sqlite3ExprListAppend(pParse, pEList,
|
| - sqlite3ExprDup(db, pRowid, 0));
|
| - }
|
| - assert( pTab->iPKey<0 );
|
| - for(i=0; i<pTab->nCol; i++){
|
| - if( aXRef[i]>=0 ){
|
| - pExpr = sqlite3ExprDup(db, pChanges->a[aXRef[i]].pExpr, 0);
|
| - }else{
|
| - pExpr = sqlite3CreateIdExpr(pParse, pTab->aCol[i].zName);
|
| - }
|
| - pEList = sqlite3ExprListAppend(pParse, pEList, pExpr);
|
| - }
|
| - pSelect = sqlite3SelectNew(pParse, pEList, pSrc, pWhere, 0, 0, 0, 0, 0, 0);
|
| -
|
| - /* Create the ephemeral table into which the update results will
|
| - ** be stored.
|
| - */
|
| - assert( v );
|
| - ephemTab = pParse->nTab++;
|
| - sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, pTab->nCol+1+(pRowid!=0));
|
| -
|
| - /* fill the ephemeral table
|
| - */
|
| - sqlite3SelectDestInit(&dest, SRT_Table, ephemTab);
|
| - sqlite3Select(pParse, pSelect, &dest);
|
| -
|
| - /* Generate code to scan the ephemeral table and call VUpdate. */
|
| - iReg = ++pParse->nMem;
|
| - pParse->nMem += pTab->nCol+1;
|
| - addr = sqlite3VdbeAddOp2(v, OP_Rewind, ephemTab, 0);
|
| - sqlite3VdbeAddOp3(v, OP_Column, ephemTab, 0, iReg);
|
| - sqlite3VdbeAddOp3(v, OP_Column, ephemTab, (pRowid?1:0), iReg+1);
|
| - for(i=0; i<pTab->nCol; i++){
|
| - sqlite3VdbeAddOp3(v, OP_Column, ephemTab, i+1+(pRowid!=0), iReg+2+i);
|
| - }
|
| - sqlite3VtabMakeWritable(pParse, pTab);
|
| - sqlite3VdbeAddOp4(v, OP_VUpdate, 0, pTab->nCol+2, iReg, pVTab, P4_VTAB);
|
| - sqlite3MayAbort(pParse);
|
| - sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr+1);
|
| - sqlite3VdbeJumpHere(v, addr);
|
| - sqlite3VdbeAddOp2(v, OP_Close, ephemTab, 0);
|
| -
|
| - /* Cleanup */
|
| - sqlite3SelectDelete(db, pSelect);
|
| -}
|
| -#endif /* SQLITE_OMIT_VIRTUALTABLE */
|
| -
|
| -/* Make sure "isView" gets undefined in case this file becomes part of
|
| -** the amalgamation - so that subsequent files do not see isView as a
|
| -** macro. */
|
| -#undef isView
|
|
|