| /* |
| ** 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 1.70.2.1 2004/04/29 16:16:29 drh Exp $ |
| */ |
| #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; |
| } |
