| /* |
| ** 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 |
| ** in order to generate code for DELETE FROM statements. |
| */ |
| #include "sqliteInt.h" |
| |
| /* |
| ** While a SrcList can in general represent multiple tables and subqueries |
| ** (as in the FROM clause of a SELECT statement) in this case it contains |
| ** the name of a single table, as one might find in an INSERT, DELETE, |
| ** or UPDATE statement. Look up that table in the symbol table and |
| ** return a pointer. Set an error message and return NULL if the table |
| ** name is not found or if any other error occurs. |
| ** |
| ** The following fields are initialized appropriate in pSrc: |
| ** |
| ** pSrc->a[0].pTab Pointer to the Table object |
| ** pSrc->a[0].pIndex Pointer to the INDEXED BY index, if there is one |
| ** |
| */ |
| Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){ |
| struct SrcList_item *pItem = pSrc->a; |
| Table *pTab; |
| assert( pItem && pSrc->nSrc==1 ); |
| pTab = sqlite3LocateTableItem(pParse, 0, pItem); |
| sqlite3DeleteTable(pParse->db, pItem->pTab); |
| pItem->pTab = pTab; |
| if( pTab ){ |
| pTab->nTabRef++; |
| } |
| if( sqlite3IndexedByLookup(pParse, pItem) ){ |
| pTab = 0; |
| } |
| return pTab; |
| } |
| |
| /* Return true if table pTab is read-only. |
| ** |
| ** A table is read-only if any of the following are true: |
| ** |
| ** 1) It is a virtual table and no implementation of the xUpdate method |
| ** has been provided |
| ** |
| ** 2) It is a system table (i.e. sqlite_master), this call is not |
| ** part of a nested parse and writable_schema pragma has not |
| ** been specified |
| ** |
| ** 3) The table is a shadow table, the database connection is in |
| ** defensive mode, and the current sqlite3_prepare() |
| ** is for a top-level SQL statement. |
| */ |
| static int tabIsReadOnly(Parse *pParse, Table *pTab){ |
| sqlite3 *db; |
| if( IsVirtual(pTab) ){ |
| return sqlite3GetVTable(pParse->db, pTab)->pMod->pModule->xUpdate==0; |
| } |
| if( (pTab->tabFlags & (TF_Readonly|TF_Shadow))==0 ) return 0; |
| db = pParse->db; |
| if( (pTab->tabFlags & TF_Readonly)!=0 ){ |
| return sqlite3WritableSchema(db)==0 && pParse->nested==0; |
| } |
| assert( pTab->tabFlags & TF_Shadow ); |
| return (db->flags & SQLITE_Defensive)!=0 |
| #ifndef SQLITE_OMIT_VIRTUALTABLE |
| && db->pVtabCtx==0 |
| #endif |
| && db->nVdbeExec==0; |
| } |
| |
| /* |
| ** Check to make sure the given table is writable. If it is not |
| ** writable, generate an error message and return 1. If it is |
| ** writable return 0; |
| */ |
| int sqlite3IsReadOnly(Parse *pParse, Table *pTab, int viewOk){ |
| if( tabIsReadOnly(pParse, pTab) ){ |
| sqlite3ErrorMsg(pParse, "table %s may not be modified", pTab->zName); |
| return 1; |
| } |
| #ifndef SQLITE_OMIT_VIEW |
| if( !viewOk && pTab->pSelect ){ |
| sqlite3ErrorMsg(pParse,"cannot modify %s because it is a view",pTab->zName); |
| return 1; |
| } |
| #endif |
| return 0; |
| } |
| |
| |
| #if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) |
| /* |
| ** Evaluate a view and store its result in an ephemeral table. The |
| ** pWhere argument is an optional WHERE clause that restricts the |
| ** set of rows in the view that are to be added to the ephemeral table. |
| */ |
| void sqlite3MaterializeView( |
| Parse *pParse, /* Parsing context */ |
| Table *pView, /* View definition */ |
| Expr *pWhere, /* Optional WHERE clause to be added */ |
| ExprList *pOrderBy, /* Optional ORDER BY clause */ |
| Expr *pLimit, /* Optional LIMIT clause */ |
| int iCur /* Cursor number for ephemeral table */ |
| ){ |
| SelectDest dest; |
| Select *pSel; |
| SrcList *pFrom; |
| sqlite3 *db = pParse->db; |
| int iDb = sqlite3SchemaToIndex(db, pView->pSchema); |
| pWhere = sqlite3ExprDup(db, pWhere, 0); |
| pFrom = sqlite3SrcListAppend(pParse, 0, 0, 0); |
| if( pFrom ){ |
| assert( pFrom->nSrc==1 ); |
| pFrom->a[0].zName = sqlite3DbStrDup(db, pView->zName); |
| pFrom->a[0].zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName); |
| assert( pFrom->a[0].pOn==0 ); |
| assert( pFrom->a[0].pUsing==0 ); |
| } |
| pSel = sqlite3SelectNew(pParse, 0, pFrom, pWhere, 0, 0, pOrderBy, |
| SF_IncludeHidden, pLimit); |
| sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur); |
| sqlite3Select(pParse, pSel, &dest); |
| sqlite3SelectDelete(db, pSel); |
| } |
| #endif /* !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) */ |
| |
| #if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY) |
| /* |
| ** Generate an expression tree to implement the WHERE, ORDER BY, |
| ** and LIMIT/OFFSET portion of DELETE and UPDATE statements. |
| ** |
| ** DELETE FROM table_wxyz WHERE a<5 ORDER BY a LIMIT 1; |
| ** \__________________________/ |
| ** pLimitWhere (pInClause) |
| */ |
| Expr *sqlite3LimitWhere( |
| Parse *pParse, /* The parser context */ |
| SrcList *pSrc, /* the FROM clause -- which tables to scan */ |
| Expr *pWhere, /* The WHERE clause. May be null */ |
| ExprList *pOrderBy, /* The ORDER BY clause. May be null */ |
| Expr *pLimit, /* The LIMIT clause. May be null */ |
| char *zStmtType /* Either DELETE or UPDATE. For err msgs. */ |
| ){ |
| sqlite3 *db = pParse->db; |
| Expr *pLhs = NULL; /* LHS of IN(SELECT...) operator */ |
| Expr *pInClause = NULL; /* WHERE rowid IN ( select ) */ |
| ExprList *pEList = NULL; /* Expression list contaning only pSelectRowid */ |
| SrcList *pSelectSrc = NULL; /* SELECT rowid FROM x ... (dup of pSrc) */ |
| Select *pSelect = NULL; /* Complete SELECT tree */ |
| Table *pTab; |
| |
| /* Check that there isn't an ORDER BY without a LIMIT clause. |
| */ |
| if( pOrderBy && pLimit==0 ) { |
| sqlite3ErrorMsg(pParse, "ORDER BY without LIMIT on %s", zStmtType); |
| sqlite3ExprDelete(pParse->db, pWhere); |
| sqlite3ExprListDelete(pParse->db, pOrderBy); |
| return 0; |
| } |
| |
| /* We only need to generate a select expression if there |
| ** is a limit/offset term to enforce. |
| */ |
| if( pLimit == 0 ) { |
| return pWhere; |
| } |
| |
| /* Generate a select expression tree to enforce the limit/offset |
| ** term for the DELETE or UPDATE statement. For example: |
| ** DELETE FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1 |
| ** becomes: |
| ** DELETE FROM table_a WHERE rowid IN ( |
| ** SELECT rowid FROM table_a WHERE col1=1 ORDER BY col2 LIMIT 1 OFFSET 1 |
| ** ); |
| */ |
| |
| pTab = pSrc->a[0].pTab; |
| if( HasRowid(pTab) ){ |
| pLhs = sqlite3PExpr(pParse, TK_ROW, 0, 0); |
| pEList = sqlite3ExprListAppend( |
| pParse, 0, sqlite3PExpr(pParse, TK_ROW, 0, 0) |
| ); |
| }else{ |
| Index *pPk = sqlite3PrimaryKeyIndex(pTab); |
| if( pPk->nKeyCol==1 ){ |
| const char *zName = pTab->aCol[pPk->aiColumn[0]].zName; |
| pLhs = sqlite3Expr(db, TK_ID, zName); |
| pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ID, zName)); |
| }else{ |
| int i; |
| for(i=0; i<pPk->nKeyCol; i++){ |
| Expr *p = sqlite3Expr(db, TK_ID, pTab->aCol[pPk->aiColumn[i]].zName); |
| pEList = sqlite3ExprListAppend(pParse, pEList, p); |
| } |
| pLhs = sqlite3PExpr(pParse, TK_VECTOR, 0, 0); |
| if( pLhs ){ |
| pLhs->x.pList = sqlite3ExprListDup(db, pEList, 0); |
| } |
| } |
| } |
| |
| /* duplicate the FROM clause as it is needed by both the DELETE/UPDATE tree |
| ** and the SELECT subtree. */ |
| pSrc->a[0].pTab = 0; |
| pSelectSrc = sqlite3SrcListDup(pParse->db, pSrc, 0); |
| pSrc->a[0].pTab = pTab; |
| pSrc->a[0].pIBIndex = 0; |
| |
| /* generate the SELECT expression tree. */ |
| pSelect = sqlite3SelectNew(pParse, pEList, pSelectSrc, pWhere, 0 ,0, |
| pOrderBy,0,pLimit |
| ); |
| |
| /* now generate the new WHERE rowid IN clause for the DELETE/UDPATE */ |
| pInClause = sqlite3PExpr(pParse, TK_IN, pLhs, 0); |
| sqlite3PExprAddSelect(pParse, pInClause, pSelect); |
| return pInClause; |
| } |
| #endif /* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) */ |
| /* && !defined(SQLITE_OMIT_SUBQUERY) */ |
| |
| /* |
| ** Generate code for a DELETE FROM statement. |
| ** |
| ** DELETE FROM table_wxyz WHERE a<5 AND b NOT NULL; |
| ** \________/ \________________/ |
| ** pTabList pWhere |
| */ |
| void sqlite3DeleteFrom( |
| Parse *pParse, /* The parser context */ |
| SrcList *pTabList, /* The table from which we should delete things */ |
| Expr *pWhere, /* The WHERE clause. May be null */ |
| ExprList *pOrderBy, /* ORDER BY clause. May be null */ |
| Expr *pLimit /* LIMIT clause. May be null */ |
| ){ |
| Vdbe *v; /* The virtual database engine */ |
| Table *pTab; /* The table from which records will be deleted */ |
| int i; /* Loop counter */ |
| WhereInfo *pWInfo; /* Information about the WHERE clause */ |
| Index *pIdx; /* For looping over indices of the table */ |
| int iTabCur; /* Cursor number for the table */ |
| int iDataCur = 0; /* VDBE cursor for the canonical data source */ |
| int iIdxCur = 0; /* Cursor number of the first index */ |
| int nIdx; /* Number of indices */ |
| sqlite3 *db; /* Main database structure */ |
| AuthContext sContext; /* Authorization context */ |
| NameContext sNC; /* Name context to resolve expressions in */ |
| int iDb; /* Database number */ |
| int memCnt = 0; /* Memory cell used for change counting */ |
| int rcauth; /* Value returned by authorization callback */ |
| int eOnePass; /* ONEPASS_OFF or _SINGLE or _MULTI */ |
| int aiCurOnePass[2]; /* The write cursors opened by WHERE_ONEPASS */ |
| u8 *aToOpen = 0; /* Open cursor iTabCur+j if aToOpen[j] is true */ |
| Index *pPk; /* The PRIMARY KEY index on the table */ |
| int iPk = 0; /* First of nPk registers holding PRIMARY KEY value */ |
| i16 nPk = 1; /* Number of columns in the PRIMARY KEY */ |
| int iKey; /* Memory cell holding key of row to be deleted */ |
| i16 nKey; /* Number of memory cells in the row key */ |
| int iEphCur = 0; /* Ephemeral table holding all primary key values */ |
| int iRowSet = 0; /* Register for rowset of rows to delete */ |
| int addrBypass = 0; /* Address of jump over the delete logic */ |
| int addrLoop = 0; /* Top of the delete loop */ |
| int addrEphOpen = 0; /* Instruction to open the Ephemeral table */ |
| int bComplex; /* True if there are triggers or FKs or |
| ** subqueries in the WHERE clause */ |
| |
| #ifndef SQLITE_OMIT_TRIGGER |
| int isView; /* True if attempting to delete from a view */ |
| Trigger *pTrigger; /* List of table triggers, if required */ |
| #endif |
| |
| memset(&sContext, 0, sizeof(sContext)); |
| db = pParse->db; |
| if( pParse->nErr || db->mallocFailed ){ |
| goto delete_from_cleanup; |
| } |
| assert( pTabList->nSrc==1 ); |
| |
| |
| /* Locate the table which we want to delete. 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. |
| */ |
| pTab = sqlite3SrcListLookup(pParse, pTabList); |
| if( pTab==0 ) goto delete_from_cleanup; |
| |
| /* Figure out if we have any triggers and if the table being |
| ** deleted from is a view |
| */ |
| #ifndef SQLITE_OMIT_TRIGGER |
| pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0); |
| isView = pTab->pSelect!=0; |
| #else |
| # define pTrigger 0 |
| # define isView 0 |
| #endif |
| bComplex = pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0); |
| #ifdef SQLITE_OMIT_VIEW |
| # undef isView |
| # define isView 0 |
| #endif |
| |
| #ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT |
| if( !isView ){ |
| pWhere = sqlite3LimitWhere( |
| pParse, pTabList, pWhere, pOrderBy, pLimit, "DELETE" |
| ); |
| pOrderBy = 0; |
| pLimit = 0; |
| } |
| #endif |
| |
| /* If pTab is really a view, make sure it has been initialized. |
| */ |
| if( sqlite3ViewGetColumnNames(pParse, pTab) ){ |
| goto delete_from_cleanup; |
| } |
| |
| if( sqlite3IsReadOnly(pParse, pTab, (pTrigger?1:0)) ){ |
| goto delete_from_cleanup; |
| } |
| iDb = sqlite3SchemaToIndex(db, pTab->pSchema); |
| assert( iDb<db->nDb ); |
| rcauth = sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, |
| db->aDb[iDb].zDbSName); |
| assert( rcauth==SQLITE_OK || rcauth==SQLITE_DENY || rcauth==SQLITE_IGNORE ); |
| if( rcauth==SQLITE_DENY ){ |
| goto delete_from_cleanup; |
| } |
| assert(!isView || pTrigger); |
| |
| /* Assign cursor numbers to the table and all its indices. |
| */ |
| assert( pTabList->nSrc==1 ); |
| iTabCur = pTabList->a[0].iCursor = pParse->nTab++; |
| for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){ |
| pParse->nTab++; |
| } |
| |
| /* Start the view context |
| */ |
| if( isView ){ |
| sqlite3AuthContextPush(pParse, &sContext, pTab->zName); |
| } |
| |
| /* Begin generating code. |
| */ |
| v = sqlite3GetVdbe(pParse); |
| if( v==0 ){ |
| goto delete_from_cleanup; |
| } |
| if( pParse->nested==0 ) sqlite3VdbeCountChanges(v); |
| sqlite3BeginWriteOperation(pParse, bComplex, iDb); |
| |
| /* If we are trying to delete from a view, realize that view into |
| ** an ephemeral table. |
| */ |
| #if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) |
| if( isView ){ |
| sqlite3MaterializeView(pParse, pTab, |
| pWhere, pOrderBy, pLimit, iTabCur |
| ); |
| iDataCur = iIdxCur = iTabCur; |
| pOrderBy = 0; |
| pLimit = 0; |
| } |
| #endif |
| |
| /* Resolve the column names in the WHERE clause. |
| */ |
| memset(&sNC, 0, sizeof(sNC)); |
| sNC.pParse = pParse; |
| sNC.pSrcList = pTabList; |
| if( sqlite3ResolveExprNames(&sNC, pWhere) ){ |
| goto delete_from_cleanup; |
| } |
| |
| /* Initialize the counter of the number of rows deleted, if |
| ** we are counting rows. |
| */ |
| if( (db->flags & SQLITE_CountRows)!=0 |
| && !pParse->nested |
| && !pParse->pTriggerTab |
| ){ |
| memCnt = ++pParse->nMem; |
| sqlite3VdbeAddOp2(v, OP_Integer, 0, memCnt); |
| } |
| |
| #ifndef SQLITE_OMIT_TRUNCATE_OPTIMIZATION |
| /* Special case: A DELETE without a WHERE clause deletes everything. |
| ** It is easier just to erase the whole table. Prior to version 3.6.5, |
| ** this optimization caused the row change count (the value returned by |
| ** API function sqlite3_count_changes) to be set incorrectly. |
| ** |
| ** The "rcauth==SQLITE_OK" terms is the |
| ** IMPLEMENTATION-OF: R-17228-37124 If the action code is SQLITE_DELETE and |
| ** the callback returns SQLITE_IGNORE then the DELETE operation proceeds but |
| ** the truncate optimization is disabled and all rows are deleted |
| ** individually. |
| */ |
| if( rcauth==SQLITE_OK |
| && pWhere==0 |
| && !bComplex |
| && !IsVirtual(pTab) |
| #ifdef SQLITE_ENABLE_PREUPDATE_HOOK |
| && db->xPreUpdateCallback==0 |
| #endif |
| ){ |
| assert( !isView ); |
| sqlite3TableLock(pParse, iDb, pTab->tnum, 1, pTab->zName); |
| if( HasRowid(pTab) ){ |
| sqlite3VdbeAddOp4(v, OP_Clear, pTab->tnum, iDb, memCnt ? memCnt : -1, |
| pTab->zName, P4_STATIC); |
| } |
| for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ |
| assert( pIdx->pSchema==pTab->pSchema ); |
| sqlite3VdbeAddOp2(v, OP_Clear, pIdx->tnum, iDb); |
| } |
| }else |
| #endif /* SQLITE_OMIT_TRUNCATE_OPTIMIZATION */ |
| { |
| u16 wcf = WHERE_ONEPASS_DESIRED|WHERE_DUPLICATES_OK|WHERE_SEEK_TABLE; |
| if( sNC.ncFlags & NC_VarSelect ) bComplex = 1; |
| wcf |= (bComplex ? 0 : WHERE_ONEPASS_MULTIROW); |
| if( HasRowid(pTab) ){ |
| /* For a rowid table, initialize the RowSet to an empty set */ |
| pPk = 0; |
| nPk = 1; |
| iRowSet = ++pParse->nMem; |
| sqlite3VdbeAddOp2(v, OP_Null, 0, iRowSet); |
| }else{ |
| /* For a WITHOUT ROWID table, create an ephemeral table used to |
| ** hold all primary keys for rows to be deleted. */ |
| pPk = sqlite3PrimaryKeyIndex(pTab); |
| assert( pPk!=0 ); |
| nPk = pPk->nKeyCol; |
| iPk = pParse->nMem+1; |
| pParse->nMem += nPk; |
| iEphCur = pParse->nTab++; |
| addrEphOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEphCur, nPk); |
| sqlite3VdbeSetP4KeyInfo(pParse, pPk); |
| } |
| |
| /* Construct a query to find the rowid or primary key for every row |
| ** to be deleted, based on the WHERE clause. Set variable eOnePass |
| ** to indicate the strategy used to implement this delete: |
| ** |
| ** ONEPASS_OFF: Two-pass approach - use a FIFO for rowids/PK values. |
| ** ONEPASS_SINGLE: One-pass approach - at most one row deleted. |
| ** ONEPASS_MULTI: One-pass approach - any number of rows may be deleted. |
| */ |
| pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0, wcf, iTabCur+1); |
| if( pWInfo==0 ) goto delete_from_cleanup; |
| eOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass); |
| assert( IsVirtual(pTab)==0 || eOnePass!=ONEPASS_MULTI ); |
| assert( IsVirtual(pTab) || bComplex || eOnePass!=ONEPASS_OFF ); |
| if( eOnePass!=ONEPASS_SINGLE ) sqlite3MultiWrite(pParse); |
| |
| /* Keep track of the number of rows to be deleted */ |
| if( memCnt ){ |
| sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1); |
| } |
| |
| /* Extract the rowid or primary key for the current row */ |
| if( pPk ){ |
| for(i=0; i<nPk; i++){ |
| assert( pPk->aiColumn[i]>=0 ); |
| sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur, |
| pPk->aiColumn[i], iPk+i); |
| } |
| iKey = iPk; |
| }else{ |
| iKey = ++pParse->nMem; |
| sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur, -1, iKey); |
| } |
| |
| if( eOnePass!=ONEPASS_OFF ){ |
| /* For ONEPASS, no need to store the rowid/primary-key. There is only |
| ** one, so just keep it in its register(s) and fall through to the |
| ** delete code. */ |
| nKey = nPk; /* OP_Found will use an unpacked key */ |
| aToOpen = sqlite3DbMallocRawNN(db, nIdx+2); |
| if( aToOpen==0 ){ |
| sqlite3WhereEnd(pWInfo); |
| goto delete_from_cleanup; |
| } |
| memset(aToOpen, 1, nIdx+1); |
| aToOpen[nIdx+1] = 0; |
| if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iTabCur] = 0; |
| if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iTabCur] = 0; |
| if( addrEphOpen ) sqlite3VdbeChangeToNoop(v, addrEphOpen); |
| }else{ |
| if( pPk ){ |
| /* Add the PK key for this row to the temporary table */ |
| iKey = ++pParse->nMem; |
| nKey = 0; /* Zero tells OP_Found to use a composite key */ |
| sqlite3VdbeAddOp4(v, OP_MakeRecord, iPk, nPk, iKey, |
| sqlite3IndexAffinityStr(pParse->db, pPk), nPk); |
| sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iEphCur, iKey, iPk, nPk); |
| }else{ |
| /* Add the rowid of the row to be deleted to the RowSet */ |
| nKey = 1; /* OP_DeferredSeek always uses a single rowid */ |
| sqlite3VdbeAddOp2(v, OP_RowSetAdd, iRowSet, iKey); |
| } |
| } |
| |
| /* If this DELETE cannot use the ONEPASS strategy, this is the |
| ** end of the WHERE loop */ |
| if( eOnePass!=ONEPASS_OFF ){ |
| addrBypass = sqlite3VdbeMakeLabel(pParse); |
| }else{ |
| sqlite3WhereEnd(pWInfo); |
| } |
| |
| /* Unless this is a view, open cursors for the table we are |
| ** deleting from and all its indices. If this is a view, then the |
| ** only effect this statement has is to fire the INSTEAD OF |
| ** triggers. |
| */ |
| if( !isView ){ |
| int iAddrOnce = 0; |
| if( eOnePass==ONEPASS_MULTI ){ |
| iAddrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v); |
| } |
| testcase( IsVirtual(pTab) ); |
| sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, OPFLAG_FORDELETE, |
| iTabCur, aToOpen, &iDataCur, &iIdxCur); |
| assert( pPk || IsVirtual(pTab) || iDataCur==iTabCur ); |
| assert( pPk || IsVirtual(pTab) || iIdxCur==iDataCur+1 ); |
| if( eOnePass==ONEPASS_MULTI ) sqlite3VdbeJumpHere(v, iAddrOnce); |
| } |
| |
| /* Set up a loop over the rowids/primary-keys that were found in the |
| ** where-clause loop above. |
| */ |
| if( eOnePass!=ONEPASS_OFF ){ |
| assert( nKey==nPk ); /* OP_Found will use an unpacked key */ |
| if( !IsVirtual(pTab) && aToOpen[iDataCur-iTabCur] ){ |
| assert( pPk!=0 || pTab->pSelect!=0 ); |
| sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, addrBypass, iKey, nKey); |
| VdbeCoverage(v); |
| } |
| }else if( pPk ){ |
| addrLoop = sqlite3VdbeAddOp1(v, OP_Rewind, iEphCur); VdbeCoverage(v); |
| if( IsVirtual(pTab) ){ |
| sqlite3VdbeAddOp3(v, OP_Column, iEphCur, 0, iKey); |
| }else{ |
| sqlite3VdbeAddOp2(v, OP_RowData, iEphCur, iKey); |
| } |
| assert( nKey==0 ); /* OP_Found will use a composite key */ |
| }else{ |
| addrLoop = sqlite3VdbeAddOp3(v, OP_RowSetRead, iRowSet, 0, iKey); |
| VdbeCoverage(v); |
| assert( nKey==1 ); |
| } |
| |
| /* Delete the row */ |
| #ifndef SQLITE_OMIT_VIRTUALTABLE |
| if( IsVirtual(pTab) ){ |
| const char *pVTab = (const char *)sqlite3GetVTable(db, pTab); |
| sqlite3VtabMakeWritable(pParse, pTab); |
| assert( eOnePass==ONEPASS_OFF || eOnePass==ONEPASS_SINGLE ); |
| sqlite3MayAbort(pParse); |
| if( eOnePass==ONEPASS_SINGLE ){ |
| sqlite3VdbeAddOp1(v, OP_Close, iTabCur); |
| if( sqlite3IsToplevel(pParse) ){ |
| pParse->isMultiWrite = 0; |
| } |
| } |
| sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iKey, pVTab, P4_VTAB); |
| sqlite3VdbeChangeP5(v, OE_Abort); |
| }else |
| #endif |
| { |
| int count = (pParse->nested==0); /* True to count changes */ |
| sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur, |
| iKey, nKey, count, OE_Default, eOnePass, aiCurOnePass[1]); |
| } |
| |
| /* End of the loop over all rowids/primary-keys. */ |
| if( eOnePass!=ONEPASS_OFF ){ |
| sqlite3VdbeResolveLabel(v, addrBypass); |
| sqlite3WhereEnd(pWInfo); |
| }else if( pPk ){ |
| sqlite3VdbeAddOp2(v, OP_Next, iEphCur, addrLoop+1); VdbeCoverage(v); |
| sqlite3VdbeJumpHere(v, addrLoop); |
| }else{ |
| sqlite3VdbeGoto(v, addrLoop); |
| sqlite3VdbeJumpHere(v, addrLoop); |
| } |
| } /* End non-truncate path */ |
| |
| /* Update the sqlite_sequence table by storing the content of the |
| ** maximum rowid counter values recorded while inserting into |
| ** autoincrement tables. |
| */ |
| if( pParse->nested==0 && pParse->pTriggerTab==0 ){ |
| sqlite3AutoincrementEnd(pParse); |
| } |
| |
| /* Return the number of rows that were deleted. If this routine is |
| ** generating code because of a call to sqlite3NestedParse(), do not |
| ** invoke the callback function. |
| */ |
| if( memCnt ){ |
| sqlite3VdbeAddOp2(v, OP_ResultRow, memCnt, 1); |
| sqlite3VdbeSetNumCols(v, 1); |
| sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows deleted", SQLITE_STATIC); |
| } |
| |
| delete_from_cleanup: |
| sqlite3AuthContextPop(&sContext); |
| sqlite3SrcListDelete(db, pTabList); |
| sqlite3ExprDelete(db, pWhere); |
| #if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) |
| sqlite3ExprListDelete(db, pOrderBy); |
| sqlite3ExprDelete(db, pLimit); |
| #endif |
| sqlite3DbFree(db, aToOpen); |
| return; |
| } |
| /* Make sure "isView" and other macros defined above are undefined. Otherwise |
| ** they may interfere with compilation of other functions in this file |
| ** (or in another file, if this file becomes part of the amalgamation). */ |
| #ifdef isView |
| #undef isView |
| #endif |
| #ifdef pTrigger |
| #undef pTrigger |
| #endif |
| |
| /* |
| ** This routine generates VDBE code that causes a single row of a |
| ** single table to be deleted. Both the original table entry and |
| ** all indices are removed. |
| ** |
| ** Preconditions: |
| ** |
| ** 1. iDataCur is an open cursor on the btree that is the canonical data |
| ** store for the table. (This will be either the table itself, |
| ** in the case of a rowid table, or the PRIMARY KEY index in the case |
| ** of a WITHOUT ROWID table.) |
| ** |
| ** 2. Read/write cursors for all indices of pTab must be open as |
| ** cursor number iIdxCur+i for the i-th index. |
| ** |
| ** 3. The primary key for the row to be deleted must be stored in a |
| ** sequence of nPk memory cells starting at iPk. If nPk==0 that means |
| ** that a search record formed from OP_MakeRecord is contained in the |
| ** single memory location iPk. |
| ** |
| ** eMode: |
| ** Parameter eMode may be passed either ONEPASS_OFF (0), ONEPASS_SINGLE, or |
| ** ONEPASS_MULTI. If eMode is not ONEPASS_OFF, then the cursor |
| ** iDataCur already points to the row to delete. If eMode is ONEPASS_OFF |
| ** then this function must seek iDataCur to the entry identified by iPk |
| ** and nPk before reading from it. |
| ** |
| ** If eMode is ONEPASS_MULTI, then this call is being made as part |
| ** of a ONEPASS delete that affects multiple rows. In this case, if |
| ** iIdxNoSeek is a valid cursor number (>=0) and is not the same as |
| ** iDataCur, then its position should be preserved following the delete |
| ** operation. Or, if iIdxNoSeek is not a valid cursor number, the |
| ** position of iDataCur should be preserved instead. |
| ** |
| ** iIdxNoSeek: |
| ** If iIdxNoSeek is a valid cursor number (>=0) not equal to iDataCur, |
| ** then it identifies an index cursor (from within array of cursors |
| ** starting at iIdxCur) that already points to the index entry to be deleted. |
| ** Except, this optimization is disabled if there are BEFORE triggers since |
| ** the trigger body might have moved the cursor. |
| */ |
| void sqlite3GenerateRowDelete( |
| Parse *pParse, /* Parsing context */ |
| Table *pTab, /* Table containing the row to be deleted */ |
| Trigger *pTrigger, /* List of triggers to (potentially) fire */ |
| int iDataCur, /* Cursor from which column data is extracted */ |
| int iIdxCur, /* First index cursor */ |
| int iPk, /* First memory cell containing the PRIMARY KEY */ |
| i16 nPk, /* Number of PRIMARY KEY memory cells */ |
| u8 count, /* If non-zero, increment the row change counter */ |
| u8 onconf, /* Default ON CONFLICT policy for triggers */ |
| u8 eMode, /* ONEPASS_OFF, _SINGLE, or _MULTI. See above */ |
| int iIdxNoSeek /* Cursor number of cursor that does not need seeking */ |
| ){ |
| Vdbe *v = pParse->pVdbe; /* Vdbe */ |
| int iOld = 0; /* First register in OLD.* array */ |
| int iLabel; /* Label resolved to end of generated code */ |
| u8 opSeek; /* Seek opcode */ |
| |
| /* Vdbe is guaranteed to have been allocated by this stage. */ |
| assert( v ); |
| VdbeModuleComment((v, "BEGIN: GenRowDel(%d,%d,%d,%d)", |
| iDataCur, iIdxCur, iPk, (int)nPk)); |
| |
| /* Seek cursor iCur to the row to delete. If this row no longer exists |
| ** (this can happen if a trigger program has already deleted it), do |
| ** not attempt to delete it or fire any DELETE triggers. */ |
| iLabel = sqlite3VdbeMakeLabel(pParse); |
| opSeek = HasRowid(pTab) ? OP_NotExists : OP_NotFound; |
| if( eMode==ONEPASS_OFF ){ |
| sqlite3VdbeAddOp4Int(v, opSeek, iDataCur, iLabel, iPk, nPk); |
| VdbeCoverageIf(v, opSeek==OP_NotExists); |
| VdbeCoverageIf(v, opSeek==OP_NotFound); |
| } |
| |
| /* If there are any triggers to fire, allocate a range of registers to |
| ** use for the old.* references in the triggers. */ |
| if( sqlite3FkRequired(pParse, pTab, 0, 0) || pTrigger ){ |
| u32 mask; /* Mask of OLD.* columns in use */ |
| int iCol; /* Iterator used while populating OLD.* */ |
| int addrStart; /* Start of BEFORE trigger programs */ |
| |
| /* TODO: Could use temporary registers here. Also could attempt to |
| ** avoid copying the contents of the rowid register. */ |
| mask = sqlite3TriggerColmask( |
| pParse, pTrigger, 0, 0, TRIGGER_BEFORE|TRIGGER_AFTER, pTab, onconf |
| ); |
| mask |= sqlite3FkOldmask(pParse, pTab); |
| iOld = pParse->nMem+1; |
| pParse->nMem += (1 + pTab->nCol); |
| |
| /* Populate the OLD.* pseudo-table register array. These values will be |
| ** used by any BEFORE and AFTER triggers that exist. */ |
| sqlite3VdbeAddOp2(v, OP_Copy, iPk, iOld); |
| for(iCol=0; iCol<pTab->nCol; iCol++){ |
| testcase( mask!=0xffffffff && iCol==31 ); |
| testcase( mask!=0xffffffff && iCol==32 ); |
| if( mask==0xffffffff || (iCol<=31 && (mask & MASKBIT32(iCol))!=0) ){ |
| sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, iCol, iOld+iCol+1); |
| } |
| } |
| |
| /* Invoke BEFORE DELETE trigger programs. */ |
| addrStart = sqlite3VdbeCurrentAddr(v); |
| sqlite3CodeRowTrigger(pParse, pTrigger, |
| TK_DELETE, 0, TRIGGER_BEFORE, pTab, iOld, onconf, iLabel |
| ); |
| |
| /* If any BEFORE triggers were coded, then seek the cursor to the |
| ** row to be deleted again. It may be that the BEFORE triggers moved |
| ** the cursor or already deleted the row that the cursor was |
| ** pointing to. |
| ** |
| ** Also disable the iIdxNoSeek optimization since the BEFORE trigger |
| ** may have moved that cursor. |
| */ |
| if( addrStart<sqlite3VdbeCurrentAddr(v) ){ |
| sqlite3VdbeAddOp4Int(v, opSeek, iDataCur, iLabel, iPk, nPk); |
| VdbeCoverageIf(v, opSeek==OP_NotExists); |
| VdbeCoverageIf(v, opSeek==OP_NotFound); |
| testcase( iIdxNoSeek>=0 ); |
| iIdxNoSeek = -1; |
| } |
| |
| /* Do FK processing. This call checks that any FK constraints that |
| ** refer to this table (i.e. constraints attached to other tables) |
| ** are not violated by deleting this row. */ |
| sqlite3FkCheck(pParse, pTab, iOld, 0, 0, 0); |
| } |
| |
| /* Delete the index and table entries. Skip this step if pTab is really |
| ** a view (in which case the only effect of the DELETE statement is to |
| ** fire the INSTEAD OF triggers). |
| ** |
| ** If variable 'count' is non-zero, then this OP_Delete instruction should |
| ** invoke the update-hook. The pre-update-hook, on the other hand should |
| ** be invoked unless table pTab is a system table. The difference is that |
| ** the update-hook is not invoked for rows removed by REPLACE, but the |
| ** pre-update-hook is. |
| */ |
| if( pTab->pSelect==0 ){ |
| u8 p5 = 0; |
| sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur,0,iIdxNoSeek); |
| sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, (count?OPFLAG_NCHANGE:0)); |
| if( pParse->nested==0 || 0==sqlite3_stricmp(pTab->zName, "sqlite_stat1") ){ |
| sqlite3VdbeAppendP4(v, (char*)pTab, P4_TABLE); |
| } |
| if( eMode!=ONEPASS_OFF ){ |
| sqlite3VdbeChangeP5(v, OPFLAG_AUXDELETE); |
| } |
| if( iIdxNoSeek>=0 && iIdxNoSeek!=iDataCur ){ |
| sqlite3VdbeAddOp1(v, OP_Delete, iIdxNoSeek); |
| } |
| if( eMode==ONEPASS_MULTI ) p5 |= OPFLAG_SAVEPOSITION; |
| sqlite3VdbeChangeP5(v, p5); |
| } |
| |
| /* Do any ON CASCADE, SET NULL or SET DEFAULT operations required to |
| ** handle rows (possibly in other tables) that refer via a foreign key |
| ** to the row just deleted. */ |
| sqlite3FkActions(pParse, pTab, 0, iOld, 0, 0); |
| |
| /* Invoke AFTER DELETE trigger programs. */ |
| sqlite3CodeRowTrigger(pParse, pTrigger, |
| TK_DELETE, 0, TRIGGER_AFTER, pTab, iOld, onconf, iLabel |
| ); |
| |
| /* Jump here if the row had already been deleted before any BEFORE |
| ** trigger programs were invoked. Or if a trigger program throws a |
| ** RAISE(IGNORE) exception. */ |
| sqlite3VdbeResolveLabel(v, iLabel); |
| VdbeModuleComment((v, "END: GenRowDel()")); |
| } |
| |
| /* |
| ** This routine generates VDBE code that causes the deletion of all |
| ** index entries associated with a single row of a single table, pTab |
| ** |
| ** Preconditions: |
| ** |
| ** 1. A read/write cursor "iDataCur" must be open on the canonical storage |
| ** btree for the table pTab. (This will be either the table itself |
| ** for rowid tables or to the primary key index for WITHOUT ROWID |
| ** tables.) |
| ** |
| ** 2. Read/write cursors for all indices of pTab must be open as |
| ** cursor number iIdxCur+i for the i-th index. (The pTab->pIndex |
| ** index is the 0-th index.) |
| ** |
| ** 3. The "iDataCur" cursor must be already be positioned on the row |
| ** that is to be deleted. |
| */ |
| void sqlite3GenerateRowIndexDelete( |
| Parse *pParse, /* Parsing and code generating context */ |
| Table *pTab, /* Table containing the row to be deleted */ |
| int iDataCur, /* Cursor of table holding data. */ |
| int iIdxCur, /* First index cursor */ |
| int *aRegIdx, /* Only delete if aRegIdx!=0 && aRegIdx[i]>0 */ |
| int iIdxNoSeek /* Do not delete from this cursor */ |
| ){ |
| int i; /* Index loop counter */ |
| int r1 = -1; /* Register holding an index key */ |
| int iPartIdxLabel; /* Jump destination for skipping partial index entries */ |
| Index *pIdx; /* Current index */ |
| Index *pPrior = 0; /* Prior index */ |
| Vdbe *v; /* The prepared statement under construction */ |
| Index *pPk; /* PRIMARY KEY index, or NULL for rowid tables */ |
| |
| v = pParse->pVdbe; |
| pPk = HasRowid(pTab) ? 0 : sqlite3PrimaryKeyIndex(pTab); |
| for(i=0, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){ |
| assert( iIdxCur+i!=iDataCur || pPk==pIdx ); |
| if( aRegIdx!=0 && aRegIdx[i]==0 ) continue; |
| if( pIdx==pPk ) continue; |
| if( iIdxCur+i==iIdxNoSeek ) continue; |
| VdbeModuleComment((v, "GenRowIdxDel for %s", pIdx->zName)); |
| r1 = sqlite3GenerateIndexKey(pParse, pIdx, iDataCur, 0, 1, |
| &iPartIdxLabel, pPrior, r1); |
| sqlite3VdbeAddOp3(v, OP_IdxDelete, iIdxCur+i, r1, |
| pIdx->uniqNotNull ? pIdx->nKeyCol : pIdx->nColumn); |
| sqlite3ResolvePartIdxLabel(pParse, iPartIdxLabel); |
| pPrior = pIdx; |
| } |
| } |
| |
| /* |
| ** Generate code that will assemble an index key and stores it in register |
| ** regOut. The key with be for index pIdx which is an index on pTab. |
| ** iCur is the index of a cursor open on the pTab table and pointing to |
| ** the entry that needs indexing. If pTab is a WITHOUT ROWID table, then |
| ** iCur must be the cursor of the PRIMARY KEY index. |
| ** |
| ** Return a register number which is the first in a block of |
| ** registers that holds the elements of the index key. The |
| ** block of registers has already been deallocated by the time |
| ** this routine returns. |
| ** |
| ** If *piPartIdxLabel is not NULL, fill it in with a label and jump |
| ** to that label if pIdx is a partial index that should be skipped. |
| ** The label should be resolved using sqlite3ResolvePartIdxLabel(). |
| ** A partial index should be skipped if its WHERE clause evaluates |
| ** to false or null. If pIdx is not a partial index, *piPartIdxLabel |
| ** will be set to zero which is an empty label that is ignored by |
| ** sqlite3ResolvePartIdxLabel(). |
| ** |
| ** The pPrior and regPrior parameters are used to implement a cache to |
| ** avoid unnecessary register loads. If pPrior is not NULL, then it is |
| ** a pointer to a different index for which an index key has just been |
| ** computed into register regPrior. If the current pIdx index is generating |
| ** its key into the same sequence of registers and if pPrior and pIdx share |
| ** a column in common, then the register corresponding to that column already |
| ** holds the correct value and the loading of that register is skipped. |
| ** This optimization is helpful when doing a DELETE or an INTEGRITY_CHECK |
| ** on a table with multiple indices, and especially with the ROWID or |
| ** PRIMARY KEY columns of the index. |
| */ |
| int sqlite3GenerateIndexKey( |
| Parse *pParse, /* Parsing context */ |
| Index *pIdx, /* The index for which to generate a key */ |
| int iDataCur, /* Cursor number from which to take column data */ |
| int regOut, /* Put the new key into this register if not 0 */ |
| int prefixOnly, /* Compute only a unique prefix of the key */ |
| int *piPartIdxLabel, /* OUT: Jump to this label to skip partial index */ |
| Index *pPrior, /* Previously generated index key */ |
| int regPrior /* Register holding previous generated key */ |
| ){ |
| Vdbe *v = pParse->pVdbe; |
| int j; |
| int regBase; |
| int nCol; |
| |
| if( piPartIdxLabel ){ |
| if( pIdx->pPartIdxWhere ){ |
| *piPartIdxLabel = sqlite3VdbeMakeLabel(pParse); |
| pParse->iSelfTab = iDataCur + 1; |
| sqlite3ExprIfFalseDup(pParse, pIdx->pPartIdxWhere, *piPartIdxLabel, |
| SQLITE_JUMPIFNULL); |
| pParse->iSelfTab = 0; |
| }else{ |
| *piPartIdxLabel = 0; |
| } |
| } |
| nCol = (prefixOnly && pIdx->uniqNotNull) ? pIdx->nKeyCol : pIdx->nColumn; |
| regBase = sqlite3GetTempRange(pParse, nCol); |
| if( pPrior && (regBase!=regPrior || pPrior->pPartIdxWhere) ) pPrior = 0; |
| for(j=0; j<nCol; j++){ |
| if( pPrior |
| && pPrior->aiColumn[j]==pIdx->aiColumn[j] |
| && pPrior->aiColumn[j]!=XN_EXPR |
| ){ |
| /* This column was already computed by the previous index */ |
| continue; |
| } |
| sqlite3ExprCodeLoadIndexColumn(pParse, pIdx, iDataCur, j, regBase+j); |
| /* If the column affinity is REAL but the number is an integer, then it |
| ** might be stored in the table as an integer (using a compact |
| ** representation) then converted to REAL by an OP_RealAffinity opcode. |
| ** But we are getting ready to store this value back into an index, where |
| ** it should be converted by to INTEGER again. So omit the OP_RealAffinity |
| ** opcode if it is present */ |
| sqlite3VdbeDeletePriorOpcode(v, OP_RealAffinity); |
| } |
| if( regOut ){ |
| sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nCol, regOut); |
| if( pIdx->pTable->pSelect ){ |
| const char *zAff = sqlite3IndexAffinityStr(pParse->db, pIdx); |
| sqlite3VdbeChangeP4(v, -1, zAff, P4_TRANSIENT); |
| } |
| } |
| sqlite3ReleaseTempRange(pParse, regBase, nCol); |
| return regBase; |
| } |
| |
| /* |
| ** If a prior call to sqlite3GenerateIndexKey() generated a jump-over label |
| ** because it was a partial index, then this routine should be called to |
| ** resolve that label. |
| */ |
| void sqlite3ResolvePartIdxLabel(Parse *pParse, int iLabel){ |
| if( iLabel ){ |
| sqlite3VdbeResolveLabel(pParse->pVdbe, iLabel); |
| } |
| } |
