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Diffstat (limited to 'src/libs/sqlite2/update.c')
| -rw-r--r-- | src/libs/sqlite2/update.c | 459 |
1 files changed, 459 insertions, 0 deletions
diff --git a/src/libs/sqlite2/update.c b/src/libs/sqlite2/update.c new file mode 100644 index 00000000..b36d0c21 --- /dev/null +++ b/src/libs/sqlite2/update.c @@ -0,0 +1,459 @@ +/* +** 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 326789 2004-07-07 21:25:56Z pahlibar $ +*/ +#include "sqliteInt.h" + +/* +** 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 sqliteUpdate( + 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 loopStart; /* VDBE instruction address of the start of the loop */ + int jumpInst; /* Addr of VDBE instruction to jump out of 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 */ + sqlite *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 chngRecno; /* True if the record number is being changed */ + Expr *pRecnoExpr; /* Expression defining the new record number */ + int openAll; /* True if all indices need to be opened */ + int isView; /* Trying to update a view */ + int iStackDepth; /* Index of memory cell holding stack depth */ + AuthContext sContext; /* The authorization context */ + + int before_triggers; /* True if there are any BEFORE triggers */ + int after_triggers; /* True if there are any AFTER triggers */ + int row_triggers_exist = 0; /* True if any row triggers exist */ + + int newIdx = -1; /* index of trigger "new" temp table */ + int oldIdx = -1; /* index of trigger "old" temp table */ + + sContext.pParse = 0; + if( pParse->nErr || sqlite_malloc_failed ) goto update_cleanup; + db = pParse->db; + assert( pTabList->nSrc==1 ); + iStackDepth = pParse->nMem++; + + /* Locate the table which we want to update. + */ + pTab = sqliteSrcListLookup(pParse, pTabList); + if( pTab==0 ) goto update_cleanup; + before_triggers = sqliteTriggersExist(pParse, pTab->pTrigger, + TK_UPDATE, TK_BEFORE, TK_ROW, pChanges); + after_triggers = sqliteTriggersExist(pParse, pTab->pTrigger, + TK_UPDATE, TK_AFTER, TK_ROW, pChanges); + row_triggers_exist = before_triggers || after_triggers; + isView = pTab->pSelect!=0; + if( sqliteIsReadOnly(pParse, pTab, before_triggers) ){ + goto update_cleanup; + } + if( isView ){ + if( sqliteViewGetColumnNames(pParse, pTab) ){ + goto update_cleanup; + } + } + aXRef = sqliteMalloc( sizeof(int) * pTab->nCol ); + if( aXRef==0 ) goto update_cleanup; + for(i=0; i<pTab->nCol; i++) aXRef[i] = -1; + + /* If there are FOR EACH ROW triggers, allocate cursors for the + ** special OLD and NEW tables + */ + if( row_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++; + } + + /* 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. + */ + chngRecno = 0; + for(i=0; i<pChanges->nExpr; i++){ + if( sqliteExprResolveIds(pParse, pTabList, 0, pChanges->a[i].pExpr) ){ + goto update_cleanup; + } + if( sqliteExprCheck(pParse, pChanges->a[i].pExpr, 0, 0) ){ + goto update_cleanup; + } + for(j=0; j<pTab->nCol; j++){ + if( sqliteStrICmp(pTab->aCol[j].zName, pChanges->a[i].zName)==0 ){ + if( j==pTab->iPKey ){ + chngRecno = 1; + pRecnoExpr = pChanges->a[i].pExpr; + } + aXRef[j] = i; + break; + } + } + if( j>=pTab->nCol ){ + if( sqliteIsRowid(pChanges->a[i].zName) ){ + chngRecno = 1; + pRecnoExpr = pChanges->a[i].pExpr; + }else{ + sqliteErrorMsg(pParse, "no such column: %s", pChanges->a[i].zName); + goto update_cleanup; + } + } +#ifndef SQLITE_OMIT_AUTHORIZATION + { + int rc; + rc = sqliteAuthCheck(pParse, SQLITE_UPDATE, pTab->zName, + pTab->aCol[j].zName, db->aDb[pTab->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( chngRecno ){ + i = 0; + }else { + for(i=0; i<pIdx->nColumn; i++){ + if( aXRef[pIdx->aiColumn[i]]>=0 ) break; + } + } + if( i<pIdx->nColumn ) nIdx++; + } + if( nIdxTotal>0 ){ + apIdx = sqliteMalloc( 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( chngRecno ){ + i = 0; + }else{ + for(i=0; i<pIdx->nColumn; i++){ + if( aXRef[pIdx->aiColumn[i]]>=0 ) break; + } + } + if( i<pIdx->nColumn ){ + apIdx[nIdx++] = pIdx; + aIdxUsed[j] = 1; + }else{ + aIdxUsed[j] = 0; + } + } + + /* Resolve the column names in all the expressions in the + ** WHERE clause. + */ + if( pWhere ){ + if( sqliteExprResolveIds(pParse, pTabList, 0, pWhere) ){ + goto update_cleanup; + } + if( sqliteExprCheck(pParse, pWhere, 0, 0) ){ + goto update_cleanup; + } + } + + /* Start the view context + */ + if( isView ){ + sqliteAuthContextPush(pParse, &sContext, pTab->zName); + } + + /* Begin generating code. + */ + v = sqliteGetVdbe(pParse); + if( v==0 ) goto update_cleanup; + sqliteBeginWriteOperation(pParse, 1, pTab->iDb); + + /* If we are trying to update a view, construct that view into + ** a temporary table. + */ + if( isView ){ + Select *pView; + pView = sqliteSelectDup(pTab->pSelect); + sqliteSelect(pParse, pView, SRT_TempTable, iCur, 0, 0, 0); + sqliteSelectDelete(pView); + } + + /* Begin the database scan + */ + pWInfo = sqliteWhereBegin(pParse, pTabList, pWhere, 1, 0); + if( pWInfo==0 ) goto update_cleanup; + + /* Remember the index of every item to be updated. + */ + sqliteVdbeAddOp(v, OP_ListWrite, 0, 0); + + /* End the database scan loop. + */ + sqliteWhereEnd(pWInfo); + + /* Initialize the count of updated rows + */ + if( db->flags & SQLITE_CountRows && !pParse->trigStack ){ + sqliteVdbeAddOp(v, OP_Integer, 0, 0); + } + + if( row_triggers_exist ){ + /* Create pseudo-tables for NEW and OLD + */ + sqliteVdbeAddOp(v, OP_OpenPseudo, oldIdx, 0); + sqliteVdbeAddOp(v, OP_OpenPseudo, newIdx, 0); + + /* The top of the update loop for when there are triggers. + */ + sqliteVdbeAddOp(v, OP_ListRewind, 0, 0); + sqliteVdbeAddOp(v, OP_StackDepth, 0, 0); + sqliteVdbeAddOp(v, OP_MemStore, iStackDepth, 1); + loopStart = sqliteVdbeAddOp(v, OP_MemLoad, iStackDepth, 0); + sqliteVdbeAddOp(v, OP_StackReset, 0, 0); + jumpInst = sqliteVdbeAddOp(v, OP_ListRead, 0, 0); + sqliteVdbeAddOp(v, OP_Dup, 0, 0); + + /* Open a cursor and make it point to the record that is + ** being updated. + */ + sqliteVdbeAddOp(v, OP_Dup, 0, 0); + if( !isView ){ + sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0); + sqliteVdbeAddOp(v, OP_OpenRead, iCur, pTab->tnum); + } + sqliteVdbeAddOp(v, OP_MoveTo, iCur, 0); + + /* Generate the OLD table + */ + sqliteVdbeAddOp(v, OP_Recno, iCur, 0); + sqliteVdbeAddOp(v, OP_RowData, iCur, 0); + sqliteVdbeAddOp(v, OP_PutIntKey, oldIdx, 0); + + /* Generate the NEW table + */ + if( chngRecno ){ + sqliteExprCode(pParse, pRecnoExpr); + }else{ + sqliteVdbeAddOp(v, OP_Recno, iCur, 0); + } + for(i=0; i<pTab->nCol; i++){ + if( i==pTab->iPKey ){ + sqliteVdbeAddOp(v, OP_String, 0, 0); + continue; + } + j = aXRef[i]; + if( j<0 ){ + sqliteVdbeAddOp(v, OP_Column, iCur, i); + }else{ + sqliteExprCode(pParse, pChanges->a[j].pExpr); + } + } + sqliteVdbeAddOp(v, OP_MakeRecord, pTab->nCol, 0); + sqliteVdbeAddOp(v, OP_PutIntKey, newIdx, 0); + if( !isView ){ + sqliteVdbeAddOp(v, OP_Close, iCur, 0); + } + + /* Fire the BEFORE and INSTEAD OF triggers + */ + if( sqliteCodeRowTrigger(pParse, TK_UPDATE, pChanges, TK_BEFORE, pTab, + newIdx, oldIdx, onError, loopStart) ){ + goto update_cleanup; + } + } + + 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. + */ + sqliteVdbeAddOp(v, OP_Integer, pTab->iDb, 0); + sqliteVdbeAddOp(v, OP_OpenWrite, iCur, pTab->tnum); + 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] ){ + sqliteVdbeAddOp(v, OP_Integer, pIdx->iDb, 0); + sqliteVdbeAddOp(v, OP_OpenWrite, iCur+i+1, pIdx->tnum); + 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 entires. + ** So make the cursor point at the old record. + */ + if( !row_triggers_exist ){ + sqliteVdbeAddOp(v, OP_ListRewind, 0, 0); + jumpInst = loopStart = sqliteVdbeAddOp(v, OP_ListRead, 0, 0); + sqliteVdbeAddOp(v, OP_Dup, 0, 0); + } + sqliteVdbeAddOp(v, OP_NotExists, iCur, loopStart); + + /* 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( chngRecno ){ + sqliteExprCode(pParse, pRecnoExpr); + sqliteVdbeAddOp(v, OP_MustBeInt, 0, 0); + } + + /* Compute new data for this record. + */ + for(i=0; i<pTab->nCol; i++){ + if( i==pTab->iPKey ){ + sqliteVdbeAddOp(v, OP_String, 0, 0); + continue; + } + j = aXRef[i]; + if( j<0 ){ + sqliteVdbeAddOp(v, OP_Column, iCur, i); + }else{ + sqliteExprCode(pParse, pChanges->a[j].pExpr); + } + } + + /* Do constraint checks + */ + sqliteGenerateConstraintChecks(pParse, pTab, iCur, aIdxUsed, chngRecno, 1, + onError, loopStart); + + /* Delete the old indices for the current record. + */ + sqliteGenerateRowIndexDelete(db, v, pTab, iCur, aIdxUsed); + + /* If changing the record number, delete the old record. + */ + if( chngRecno ){ + sqliteVdbeAddOp(v, OP_Delete, iCur, 0); + } + + /* Create the new index entries and the new record. + */ + sqliteCompleteInsertion(pParse, pTab, iCur, aIdxUsed, chngRecno, 1, -1); + } + + /* Increment the row counter + */ + if( db->flags & SQLITE_CountRows && !pParse->trigStack){ + sqliteVdbeAddOp(v, OP_AddImm, 1, 0); + } + + /* If there are triggers, close all the cursors after each iteration + ** through the loop. The fire the after triggers. + */ + if( row_triggers_exist ){ + if( !isView ){ + for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){ + if( openAll || aIdxUsed[i] ) + sqliteVdbeAddOp(v, OP_Close, iCur+i+1, 0); + } + sqliteVdbeAddOp(v, OP_Close, iCur, 0); + pParse->nTab = iCur; + } + if( sqliteCodeRowTrigger(pParse, TK_UPDATE, pChanges, TK_AFTER, pTab, + newIdx, oldIdx, onError, loopStart) ){ + goto update_cleanup; + } + } + + /* Repeat the above with the next record to be updated, until + ** all record selected by the WHERE clause have been updated. + */ + sqliteVdbeAddOp(v, OP_Goto, 0, loopStart); + sqliteVdbeChangeP2(v, jumpInst, sqliteVdbeCurrentAddr(v)); + sqliteVdbeAddOp(v, OP_ListReset, 0, 0); + + /* Close all tables if there were no FOR EACH ROW triggers */ + if( !row_triggers_exist ){ + for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){ + if( openAll || aIdxUsed[i] ){ + sqliteVdbeAddOp(v, OP_Close, iCur+i+1, 0); + } + } + sqliteVdbeAddOp(v, OP_Close, iCur, 0); + pParse->nTab = iCur; + }else{ + sqliteVdbeAddOp(v, OP_Close, newIdx, 0); + sqliteVdbeAddOp(v, OP_Close, oldIdx, 0); + } + + sqliteVdbeAddOp(v, OP_SetCounts, 0, 0); + sqliteEndWriteOperation(pParse); + + /* + ** Return the number of rows that were changed. + */ + if( db->flags & SQLITE_CountRows && !pParse->trigStack ){ + sqliteVdbeOp3(v, OP_ColumnName, 0, 1, "rows updated", P3_STATIC); + sqliteVdbeAddOp(v, OP_Callback, 1, 0); + } + +update_cleanup: + sqliteAuthContextPop(&sContext); + sqliteFree(apIdx); + sqliteFree(aXRef); + sqliteSrcListDelete(pTabList); + sqliteExprListDelete(pChanges); + sqliteExprDelete(pWhere); + return; +} |