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Diffstat (limited to 'src/sqlite/update.c')
| -rw-r--r-- | src/sqlite/update.c | 505 |
1 files changed, 505 insertions, 0 deletions
diff --git a/src/sqlite/update.c b/src/sqlite/update.c new file mode 100644 index 0000000..47bfe13 --- /dev/null +++ b/src/sqlite/update.c @@ -0,0 +1,505 @@ +/* +** 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 1.1.1.1 2006/02/03 20:35:11 hoganrobert Exp $ +*/ +#include "sqliteInt.h" + +/* +** The most recently coded instruction was an OP_Column to retrieve column +** 'i' 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 = sqlite3VdbeDb(v)->enc; + Column *pCol = &pTab->aCol[i]; + sqlite3ValueFromExpr(pCol->pDflt, enc, pCol->affinity, &pValue); + sqlite3VdbeChangeP3(v, -1, (const char *)pValue, P3_MEM); + } +} + +/* +** 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 */ + +#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; + if( pParse->nErr || sqlite3_malloc_failed ) goto update_cleanup; + db = pParse->db; + assert( pTabList->nSrc==1 ); + + /* Locate the table which we want to update. + */ + pTab = sqlite3SrcListLookup(pParse, pTabList); + if( pTab==0 ) goto update_cleanup; + + /* 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( isView ){ + if( sqlite3ViewGetColumnNames(pParse, pTab) ){ + goto update_cleanup; + } + } + aXRef = sqliteMallocRaw( 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( 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; i<pChanges->nExpr; i++){ + if( sqlite3ExprResolveNames(&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[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( chngRowid ){ + 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 = sqliteMallocRaw( 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; i<pIdx->nColumn; i++){ + if( aXRef[pIdx->aiColumn[i]]>=0 ) break; + } + } + if( i<pIdx->nColumn ){ + if( sqlite3CheckIndexCollSeq(pParse, pIdx) ) goto update_cleanup; + apIdx[nIdx++] = pIdx; + aIdxUsed[j] = 1; + }else{ + aIdxUsed[j] = 0; + } + } + + /* 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); + } + + /* Begin generating code. + */ + v = sqlite3GetVdbe(pParse); + if( v==0 ) goto update_cleanup; + if( pParse->nested==0 ) sqlite3VdbeCountChanges(v); + sqlite3BeginWriteOperation(pParse, 1, pTab->iDb); + + /* If we are trying to update a view, construct that view into + ** a temporary table. + */ + if( isView ){ + Select *pView; + pView = sqlite3SelectDup(pTab->pSelect); + sqlite3Select(pParse, pView, SRT_TempTable, 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 index of every item to be updated. + */ + sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0); + sqlite3VdbeAddOp(v, OP_ListWrite, 0, 0); + + /* End the database scan loop. + */ + sqlite3WhereEnd(pWInfo); + + /* Initialize the count of updated rows + */ + if( db->flags & SQLITE_CountRows && !pParse->trigStack ){ + sqlite3VdbeAddOp(v, OP_Integer, 0, 0); + } + + 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. + */ + sqlite3VdbeAddOp(v, OP_ListRewind, 0, 0); + addr = sqlite3VdbeAddOp(v, OP_ListRead, 0, 0); + + if( !isView ){ + sqlite3VdbeAddOp(v, OP_Dup, 0, 0); + sqlite3VdbeAddOp(v, OP_Dup, 0, 0); + /* Open a cursor and make it point to the record that is + ** being updated. + */ + sqlite3OpenTableForReading(v, iCur, pTab); + } + sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0); + + /* 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; i<pTab->nCol; 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 ){ + /* + ** 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. + */ + sqlite3VdbeAddOp(v, OP_Integer, pTab->iDb, 0); + sqlite3VdbeAddOp(v, OP_OpenWrite, iCur, pTab->tnum); + sqlite3VdbeAddOp(v, OP_SetNumColumns, iCur, pTab->nCol); + 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] ){ + sqlite3VdbeAddOp(v, OP_Integer, pIdx->iDb, 0); + sqlite3VdbeOp3(v, OP_OpenWrite, iCur+i+1, pIdx->tnum, + (char*)&pIdx->keyInfo, P3_KEYINFO); + 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( !triggers_exist ){ + sqlite3VdbeAddOp(v, OP_ListRewind, 0, 0); + addr = sqlite3VdbeAddOp(v, OP_ListRead, 0, 0); + sqlite3VdbeAddOp(v, OP_Dup, 0, 0); + } + sqlite3VdbeAddOp(v, OP_NotExists, iCur, 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( chngRowid ){ + sqlite3ExprCode(pParse, pRowidExpr); + sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0); + } + + /* Compute new data for this record. + */ + for(i=0; i<pTab->nCol; 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(db, 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); + } + + /* Increment the row counter + */ + if( db->flags & SQLITE_CountRows && !pParse->trigStack){ + sqlite3VdbeAddOp(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( 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); + sqlite3VdbeChangeP2(v, addr, sqlite3VdbeCurrentAddr(v)); + sqlite3VdbeAddOp(v, OP_ListReset, 0, 0); + + /* 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_Callback, 1, 0); + sqlite3VdbeSetNumCols(v, 1); + sqlite3VdbeSetColName(v, 0, "rows updated", P3_STATIC); + } + +update_cleanup: + sqlite3AuthContextPop(&sContext); + sqliteFree(apIdx); + sqliteFree(aXRef); + sqlite3SrcListDelete(pTabList); + sqlite3ExprListDelete(pChanges); + sqlite3ExprDelete(pWhere); + return; +} |