diff options
Diffstat (limited to 'ext/sqlite/libsqlite/src/update.c')
| -rw-r--r-- | ext/sqlite/libsqlite/src/update.c | 415 |
1 files changed, 415 insertions, 0 deletions
diff --git a/ext/sqlite/libsqlite/src/update.c b/ext/sqlite/libsqlite/src/update.c new file mode 100644 index 0000000000..b5825dd12e --- /dev/null +++ b/ext/sqlite/libsqlite/src/update.c @@ -0,0 +1,415 @@ +/* +** 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. +** +** $Id$ +*/ +#include "sqliteInt.h" + +/* +** Process an UPDATE statement. +*/ +void sqliteUpdate( + Parse *pParse, /* The parser context */ + Token *pTableName, /* 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 */ + SrcList *pTabList = 0; /* Fake FROM clause containing only pTab */ + int addr; /* 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 base; /* Index of first available table cursor */ + sqlite *db; /* The database structure */ + Index **apIdx = 0; /* An array of indices that need updating too */ + char *aIdxUsed = 0; /* aIdxUsed[i] 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 openOp; /* Opcode used to open tables */ + 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 row_triggers_exist = 0; + + int newIdx = -1; /* index of trigger "new" temp table */ + int oldIdx = -1; /* index of trigger "old" temp table */ + + if( pParse->nErr || sqlite_malloc_failed ) goto update_cleanup; + db = pParse->db; + + /* Check for the special case of a VIEW with one or more ON UPDATE triggers + * defined + */ + { + char *zTab = sqliteTableNameFromToken(pTableName); + + if( zTab != 0 ){ + pTab = sqliteFindTable(pParse->db, zTab); + if( pTab ){ + row_triggers_exist = + sqliteTriggersExist(pParse, pTab->pTrigger, + TK_UPDATE, TK_BEFORE, TK_ROW, pChanges) || + sqliteTriggersExist(pParse, pTab->pTrigger, + TK_UPDATE, TK_AFTER, TK_ROW, pChanges); + } + sqliteFree(zTab); + if( row_triggers_exist && pTab->pSelect ){ + /* Just fire VIEW triggers */ + sqliteViewTriggers(pParse, pTab, pWhere, onError, pChanges); + return; + } + } + } + + /* Locate the table which we want to update. This table has to be + ** put in an SrcList structure because some of the subroutines we + ** will be calling are designed to work with multiple tables and expect + ** an SrcList* parameter instead of just a Table* parameter. + */ + pTabList = sqliteTableTokenToSrcList(pParse, pTableName); + if( pTabList==0 ) goto update_cleanup; + pTab = pTabList->a[0].pTab; + assert( pTab->pSelect==0 ); /* This table is not a VIEW */ + 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 temp 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. + */ + base = pParse->nTab++; + for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ + pParse->nTab++; + } + + /* Resolve the column names in all the expressions in both the + ** WHERE clause and in the new values. 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. + */ + if( pWhere ){ + if( sqliteExprResolveIds(pParse, base, pTabList, 0, pWhere) ){ + goto update_cleanup; + } + if( sqliteExprCheck(pParse, pWhere, 0, 0) ){ + goto update_cleanup; + } + } + chngRecno = 0; + for(i=0; i<pChanges->nExpr; i++){ + if( sqliteExprResolveIds(pParse, base, 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 ){ + sqliteSetString(&pParse->zErrMsg, "no such column: ", + pChanges->a[i].zName, 0); + pParse->nErr++; + goto update_cleanup; + } +#ifndef SQLITE_OMIT_AUTHORIZATION + { + int rc; + rc = sqliteAuthCheck(pParse, SQLITE_UPDATE, pTab->zName, + pTab->aCol[j].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; + } + } + + /* Begin generating code. + */ + v = sqliteGetVdbe(pParse); + if( v==0 ) goto update_cleanup; + sqliteBeginWriteOperation(pParse, 1, !row_triggers_exist && pTab->isTemp); + + /* Begin the database scan + */ + pWInfo = sqliteWhereBegin(pParse, base, 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 ){ + int ii; + + sqliteVdbeAddOp(v, OP_OpenTemp, oldIdx, 0); + sqliteVdbeAddOp(v, OP_OpenTemp, newIdx, 0); + + sqliteVdbeAddOp(v, OP_ListRewind, 0, 0); + addr = sqliteVdbeAddOp(v, OP_ListRead, 0, 0); + sqliteVdbeAddOp(v, OP_Dup, 0, 0); + + sqliteVdbeAddOp(v, OP_Dup, 0, 0); + sqliteVdbeAddOp(v, (pTab->isTemp?OP_OpenAux:OP_Open), base, pTab->tnum); + sqliteVdbeAddOp(v, OP_MoveTo, base, 0); + + sqliteVdbeAddOp(v, OP_Integer, 13, 0); + for(ii = 0; ii < pTab->nCol; ii++){ + if( ii == pTab->iPKey ){ + sqliteVdbeAddOp(v, OP_Recno, base, 0); + }else{ + sqliteVdbeAddOp(v, OP_Column, base, ii); + } + } + sqliteVdbeAddOp(v, OP_MakeRecord, pTab->nCol, 0); + sqliteVdbeAddOp(v, OP_PutIntKey, oldIdx, 0); + + sqliteVdbeAddOp(v, OP_Integer, 13, 0); + for(ii = 0; ii < pTab->nCol; ii++){ + if( aXRef[ii] < 0 ){ + if( ii == pTab->iPKey ){ + sqliteVdbeAddOp(v, OP_Recno, base, 0); + }else{ + sqliteVdbeAddOp(v, OP_Column, base, ii); + } + }else{ + sqliteExprCode(pParse, pChanges->a[aXRef[ii]].pExpr); + } + } + sqliteVdbeAddOp(v, OP_MakeRecord, pTab->nCol, 0); + sqliteVdbeAddOp(v, OP_PutIntKey, newIdx, 0); + sqliteVdbeAddOp(v, OP_Close, base, 0); + + sqliteVdbeAddOp(v, OP_Rewind, oldIdx, 0); + sqliteVdbeAddOp(v, OP_Rewind, newIdx, 0); + + if( sqliteCodeRowTrigger(pParse, TK_UPDATE, pChanges, TK_BEFORE, pTab, + newIdx, oldIdx, onError, addr) ){ + goto update_cleanup; + } + } + + /* Rewind the list of records that need to be updated and + ** 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. + */ + openOp = pTab->isTemp ? OP_OpenWrAux : OP_OpenWrite; + sqliteVdbeAddOp(v, openOp, base, 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, openOp, base+i+1, pIdx->tnum); + assert( pParse->nTab>base+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); + addr = sqliteVdbeAddOp(v, OP_ListRead, 0, 0); + sqliteVdbeAddOp(v, OP_Dup, 0, 0); + } + sqliteVdbeAddOp(v, OP_NotExists, base, addr); + + /* 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, base, i); + }else{ + sqliteExprCode(pParse, pChanges->a[j].pExpr); + } + } + + /* Do constraint checks + */ + sqliteGenerateConstraintChecks(pParse, pTab, base, aIdxUsed, chngRecno, 1, + onError, addr); + + /* Delete the old indices for the current record. + */ + sqliteGenerateRowIndexDelete(db, v, pTab, base, aIdxUsed); + + /* If changing the record number, delete the old record. + */ + if( chngRecno ){ + sqliteVdbeAddOp(v, OP_Delete, base, 0); + } + + /* Create the new index entries and the new record. + */ + sqliteCompleteInsertion(pParse, pTab, base, aIdxUsed, chngRecno, 1); + + /* Increment the row counter + */ + if( db->flags & SQLITE_CountRows && !pParse->trigStack){ + sqliteVdbeAddOp(v, OP_AddImm, 1, 0); + } + + if( row_triggers_exist ){ + for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){ + if( openAll || aIdxUsed[i] ) + sqliteVdbeAddOp(v, OP_Close, base+i+1, 0); + } + sqliteVdbeAddOp(v, OP_Close, base, 0); + pParse->nTab = base; + + if( sqliteCodeRowTrigger(pParse, TK_UPDATE, pChanges, TK_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. + */ + sqliteVdbeAddOp(v, OP_Goto, 0, addr); + sqliteVdbeChangeP2(v, addr, 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, base+i+1, 0); + } + } + sqliteVdbeAddOp(v, OP_Close, base, 0); + pParse->nTab = base; + }else{ + sqliteVdbeAddOp(v, OP_Close, newIdx, 0); + sqliteVdbeAddOp(v, OP_Close, oldIdx, 0); + } + + sqliteEndWriteOperation(pParse); + + /* + ** Return the number of rows that were changed. + */ + if( db->flags & SQLITE_CountRows && !pParse->trigStack ){ + sqliteVdbeAddOp(v, OP_ColumnName, 0, 0); + sqliteVdbeChangeP3(v, -1, "rows updated", P3_STATIC); + sqliteVdbeAddOp(v, OP_Callback, 1, 0); + } + +update_cleanup: + sqliteFree(apIdx); + sqliteFree(aXRef); + sqliteSrcListDelete(pTabList); + sqliteExprListDelete(pChanges); + sqliteExprDelete(pWhere); + return; +} |