diff -r 87e863f6f840 -r 3903521a36da engine/sqlite/src/update.cpp --- a/engine/sqlite/src/update.cpp Wed May 26 10:44:32 2010 +0100 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,639 +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.cpp 1282 2008-11-13 09:31:33Z LarsPson $ -*/ -#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 P3 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 P3 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 P3 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 P3 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. -*/ -void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){ - if( pTab && !pTab->pSelect ){ - sqlite3_value *pValue; - u8 enc = ENC(sqlite3VdbeDb(v)); - Column *pCol = &pTab->aCol[i]; - assert( inCol ); - sqlite3ValueFromExpr(sqlite3VdbeDb(v), pCol->pDflt, enc, pCol->affinity, &pValue); - if( pValue ){ - sqlite3VdbeChangeP3(v, -1, (const char *)pValue, P3_MEM); - }else{ - VdbeComment((v, "# %s.%s", pTab->zName, pCol->zName)); - } - } -} - -/* -** 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 nIdxTotal; /* Total number of indices */ - int iCur; /* VDBE Cursor number of pTab */ - sqlite3 *db; /* The database structure */ - Index **apIdx = 0; /* An array of indices that need updating too */ - char *aIdxUsed = 0; /* aIdxUsed[i]==1 if the i-th index is used */ - 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 memCnt = 0; /* Memory cell used for counting rows changed */ - int mem1; /* Memory address storing the rowid for next row to update */ - -#ifndef SQLITE_OMIT_TRIGGER - int isView; /* Trying to update a view */ - int triggers_exist = 0; /* True if any row triggers exist */ -#endif - - int newIdx = -1; /* index of trigger "new" temp table */ - int oldIdx = -1; /* index of trigger "old" temp table */ - - sContext.pParse = 0; - 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 - triggers_exist = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges); - isView = pTab->pSelect!=0; -#else -# define triggers_exist 0 -# define isView 0 -#endif -#ifdef SQLITE_OMIT_VIEW -# undef isView -# define isView 0 -#endif - - if( sqlite3IsReadOnly(pParse, pTab, triggers_exist) ){ - goto update_cleanup; - } - if( sqlite3ViewGetColumnNames(pParse, pTab) ){ - goto update_cleanup; - } - aXRef = (int*)sqlite3DbMallocRaw(db, sizeof(int) * pTab->nCol ); - if( aXRef==0 ) goto update_cleanup; - for(i=0; inCol; i++) aXRef[i] = -1; - - /* If there are FOR EACH ROW triggers, allocate cursors for the - ** special OLD and NEW tables - */ - if( triggers_exist ){ - newIdx = pParse->nTab++; - oldIdx = pParse->nTab++; - } - - /* 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; inExpr; i++){ - if( sqlite3ExprResolveNames(&sNC, pChanges->a[i].pExpr) ){ - goto update_cleanup; - } - for(j=0; jnCol; 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 apIdx[] and fill it with pointers to every - ** index that needs to be updated. Indices only need updating if their - ** key includes one of the columns named in pChanges or if the record - ** number of the original table entry is changing. - */ - for(nIdx=nIdxTotal=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdxTotal++){ - if( chngRowid ){ - i = 0; - }else { - for(i=0; inColumn; i++){ - if( aXRef[pIdx->aiColumn[i]]>=0 ) break; - } - } - if( inColumn ) nIdx++; - } - if( nIdxTotal>0 ){ - apIdx = (Index**)sqlite3DbMallocRaw(db, sizeof(Index*) * nIdx + nIdxTotal ); - if( apIdx==0 ) goto update_cleanup; - aIdxUsed = (char*)&apIdx[nIdx]; - } - for(nIdx=j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){ - if( chngRowid ){ - i = 0; - }else{ - for(i=0; inColumn; i++){ - if( aXRef[pIdx->aiColumn[i]]>=0 ) break; - } - } - if( inColumn ){ - apIdx[nIdx++] = pIdx; - aIdxUsed[j] = 1; - }else{ - aIdxUsed[j] = 0; - } - } - - /* Begin generating code. - */ - v = sqlite3GetVdbe(pParse); - if( v==0 ) goto update_cleanup; - if( pParse->nested==0 ) sqlite3VdbeCountChanges(v); - sqlite3BeginWriteOperation(pParse, 1, iDb); - mem1 = pParse->nMem++; - -#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 - - /* Resolve the column names in all the expressions in the - ** WHERE clause. - */ - if( sqlite3ExprResolveNames(&sNC, pWhere) ){ - goto update_cleanup; - } - - /* Start the view context - */ - if( isView ){ - sqlite3AuthContextPush(pParse, &sContext, pTab->zName); - } - - /* If we are trying to update a view, realize that view into - ** a ephemeral table. - */ - if( isView ){ - Select *pView; - pView = sqlite3SelectDup(db, pTab->pSelect); - sqlite3Select(pParse, pView, SRT_EphemTab, iCur, 0, 0, 0, 0); - sqlite3SelectDelete(pView); - } - - /* Begin the database scan - */ - pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0); - if( pWInfo==0 ) goto update_cleanup; - - /* Remember the rowid of every item to be updated. - */ - sqlite3VdbeAddOp(v, IsVirtual(pTab) ? OP_VRowid : OP_Rowid, iCur, 0); - sqlite3VdbeAddOp(v, OP_FifoWrite, 0, 0); - - /* End the database scan loop. - */ - sqlite3WhereEnd(pWInfo); - - /* Initialize the count of updated rows - */ - if( db->flags & SQLITE_CountRows && !pParse->trigStack ){ - memCnt = pParse->nMem++; - sqlite3VdbeAddOp(v, OP_MemInt, 0, memCnt); - } - - if( triggers_exist ){ - - /* Create pseudo-tables for NEW and OLD - */ - sqlite3VdbeAddOp(v, OP_OpenPseudo, oldIdx, 0); - sqlite3VdbeAddOp(v, OP_SetNumColumns, oldIdx, pTab->nCol); - sqlite3VdbeAddOp(v, OP_OpenPseudo, newIdx, 0); - sqlite3VdbeAddOp(v, OP_SetNumColumns, newIdx, pTab->nCol); - - /* The top of the update loop for when there are triggers. - */ - addr = sqlite3VdbeAddOp(v, OP_FifoRead, 0, 0); - sqlite3VdbeAddOp(v, OP_StackDepth, -1, 0); - sqlite3VdbeAddOp(v, OP_MemStore, mem1, 0); - - if( !isView ){ - /* Open a cursor and make it point to the record that is - ** being updated. - */ - sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenRead); - } - sqlite3VdbeAddOp(v, OP_NotExists, iCur, addr); - - /* Generate the OLD table - */ - sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0); - sqlite3VdbeAddOp(v, OP_RowData, iCur, 0); - sqlite3VdbeAddOp(v, OP_Insert, oldIdx, 0); - - /* Generate the NEW table - */ - if( chngRowid ){ - sqlite3ExprCodeAndCache(pParse, pRowidExpr); - }else{ - sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0); - } - for(i=0; inCol; i++){ - if( i==pTab->iPKey ){ - sqlite3VdbeAddOp(v, OP_Null, 0, 0); - continue; - } - j = aXRef[i]; - if( j<0 ){ - sqlite3VdbeAddOp(v, OP_Column, iCur, i); - sqlite3ColumnDefault(v, pTab, i); - }else{ - sqlite3ExprCodeAndCache(pParse, pChanges->a[j].pExpr); - } - } - sqlite3VdbeAddOp(v, OP_MakeRecord, pTab->nCol, 0); - if( !isView ){ - sqlite3TableAffinityStr(v, pTab); - } - if( pParse->nErr ) goto update_cleanup; - sqlite3VdbeAddOp(v, OP_Insert, newIdx, 0); - if( !isView ){ - sqlite3VdbeAddOp(v, OP_Close, iCur, 0); - } - - /* Fire the BEFORE and INSTEAD OF triggers - */ - if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_BEFORE, pTab, - newIdx, oldIdx, onError, addr) ){ - goto update_cleanup; - } - - if( !isView ){ - sqlite3VdbeAddOp(v, OP_MemLoad, mem1, 0); - } - } - - if( !isView && !IsVirtual(pTab) ){ - /* - ** 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. - */ - 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 || aIdxUsed[i] ){ - KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx); - sqlite3VdbeAddOp(v, OP_Integer, iDb, 0); - sqlite3VdbeOp3(v, OP_OpenWrite, iCur+i+1, pIdx->tnum, - (char*)pKey, P3_KEYINFO_HANDOFF); - assert( pParse->nTab>iCur+i+1 ); - } - } - - /* Loop over every record that needs updating. We have to load - ** the old data for each record to be updated because some columns - ** might not change and we will need to copy the old value. - ** Also, the old data is needed to delete the old index entries. - ** So make the cursor point at the old record. - */ - if( !triggers_exist ){ - addr = sqlite3VdbeAddOp(v, OP_FifoRead, 0, 0); - sqlite3VdbeAddOp(v, OP_StackDepth, -1, 0); - sqlite3VdbeAddOp(v, OP_MemStore, mem1, 0); - } - sqlite3VdbeAddOp(v, OP_NotExists, iCur, addr); - sqlite3VdbeAddOp(v, OP_MemLoad, mem1, 0); - - /* If the record number will change, push the record number as it - ** will be after the update. (The old record number is currently - ** on top of the stack.) - */ - if( chngRowid ){ - sqlite3ExprCode(pParse, pRowidExpr); - sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0); - } - - /* Compute new data for this record. - */ - for(i=0; inCol; i++){ - if( i==pTab->iPKey ){ - sqlite3VdbeAddOp(v, OP_Null, 0, 0); - continue; - } - j = aXRef[i]; - if( j<0 ){ - sqlite3VdbeAddOp(v, OP_Column, iCur, i); - sqlite3ColumnDefault(v, pTab, i); - }else{ - sqlite3ExprCode(pParse, pChanges->a[j].pExpr); - } - } - - /* Do constraint checks - */ - sqlite3GenerateConstraintChecks(pParse, pTab, iCur, aIdxUsed, chngRowid, 1, - onError, addr); - - /* Delete the old indices for the current record. - */ - sqlite3GenerateRowIndexDelete(v, pTab, iCur, aIdxUsed); - - /* If changing the record number, delete the old record. - */ - if( chngRowid ){ - sqlite3VdbeAddOp(v, OP_Delete, iCur, 0); - } - - /* Create the new index entries and the new record. - */ - sqlite3CompleteInsertion(pParse, pTab, iCur, aIdxUsed, chngRowid, 1, -1, 0); - } - - /* Increment the row counter - */ - if( db->flags & SQLITE_CountRows && !pParse->trigStack){ - sqlite3VdbeAddOp(v, OP_MemIncr, 1, memCnt); - } - - /* If there are triggers, close all the cursors after each iteration - ** through the loop. The fire the after triggers. - */ - if( triggers_exist ){ - if( !isView ){ - for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){ - if( openAll || aIdxUsed[i] ) - sqlite3VdbeAddOp(v, OP_Close, iCur+i+1, 0); - } - sqlite3VdbeAddOp(v, OP_Close, iCur, 0); - } - if( sqlite3CodeRowTrigger(pParse, TK_UPDATE, pChanges, TRIGGER_AFTER, pTab, - newIdx, oldIdx, onError, addr) ){ - goto update_cleanup; - } - } - - /* Repeat the above with the next record to be updated, until - ** all record selected by the WHERE clause have been updated. - */ - sqlite3VdbeAddOp(v, OP_Goto, 0, addr); - sqlite3VdbeJumpHere(v, addr); - - /* Close all tables if there were no FOR EACH ROW triggers */ - if( !triggers_exist ){ - for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){ - if( openAll || aIdxUsed[i] ){ - sqlite3VdbeAddOp(v, OP_Close, iCur+i+1, 0); - } - } - sqlite3VdbeAddOp(v, OP_Close, iCur, 0); - }else{ - sqlite3VdbeAddOp(v, OP_Close, newIdx, 0); - sqlite3VdbeAddOp(v, OP_Close, oldIdx, 0); - } - - /* - ** 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->trigStack && pParse->nested==0 ){ - sqlite3VdbeAddOp(v, OP_MemLoad, memCnt, 0); - sqlite3VdbeAddOp(v, OP_Callback, 1, 0); - sqlite3VdbeSetNumCols(v, 1); - sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows updated", P3_STATIC); - } - -update_cleanup: - sqlite3AuthContextPop(&sContext); - sqlite3_free(apIdx); - sqlite3_free(aXRef); - sqlite3SrcListDelete(pTabList); - sqlite3ExprListDelete(pChanges); - sqlite3ExprDelete(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 */ - sqlite3 *db = pParse->db; /* Database connection */ - - /* Construct the SELECT statement that will find the new values for - ** all updated rows. - */ - pEList = sqlite3ExprListAppend(pParse, 0, - sqlite3CreateIdExpr(pParse, "_rowid_"), 0); - if( pRowid ){ - pEList = sqlite3ExprListAppend(pParse, pEList, - sqlite3ExprDup(db, pRowid), 0); - } - assert( pTab->iPKey<0 ); - for(i=0; inCol; i++){ - if( aXRef[i]>=0 ){ - pExpr = sqlite3ExprDup(db, pChanges->a[aXRef[i]].pExpr); - }else{ - pExpr = sqlite3CreateIdExpr(pParse, pTab->aCol[i].zName); - } - pEList = sqlite3ExprListAppend(pParse, pEList, pExpr, 0); - } - 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++; - sqlite3VdbeAddOp(v, OP_OpenEphemeral, ephemTab, pTab->nCol+1+(pRowid!=0)); - - /* fill the ephemeral table - */ - sqlite3Select(pParse, pSelect, SRT_Table, ephemTab, 0, 0, 0, 0); - - /* - ** Generate code to scan the ephemeral table and call VDelete and - ** VInsert - */ - sqlite3VdbeAddOp(v, OP_Rewind, ephemTab, 0); - addr = sqlite3VdbeCurrentAddr(v); - sqlite3VdbeAddOp(v, OP_Column, ephemTab, 0); - if( pRowid ){ - sqlite3VdbeAddOp(v, OP_Column, ephemTab, 1); - }else{ - sqlite3VdbeAddOp(v, OP_Dup, 0, 0); - } - for(i=0; inCol; i++){ - sqlite3VdbeAddOp(v, OP_Column, ephemTab, i+1+(pRowid!=0)); - } - pParse->pVirtualLock = pTab; - sqlite3VdbeOp3(v, OP_VUpdate, 0, pTab->nCol+2, - (const char*)pTab->pVtab, P3_VTAB); - sqlite3VdbeAddOp(v, OP_Next, ephemTab, addr); - sqlite3VdbeJumpHere(v, addr-1); - sqlite3VdbeAddOp(v, OP_Close, ephemTab, 0); - - /* Cleanup */ - sqlite3SelectDelete(pSelect); -} -#endif /* SQLITE_OMIT_VIRTUALTABLE */