1.1 --- a/extensions/sqlite/sqlite-source/delete.c Fri Mar 28 06:21:34 2008 +0000
1.2 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000
1.3 @@ -1,467 +0,0 @@
1.4 -/*
1.5 -** 2001 September 15
1.6 -**
1.7 -** The author disclaims copyright to this source code. In place of
1.8 -** a legal notice, here is a blessing:
1.9 -**
1.10 -** May you do good and not evil.
1.11 -** May you find forgiveness for yourself and forgive others.
1.12 -** May you share freely, never taking more than you give.
1.13 -**
1.14 -*************************************************************************
1.15 -** This file contains C code routines that are called by the parser
1.16 -** in order to generate code for DELETE FROM statements.
1.17 -**
1.18 -** $Id$
1.19 -*/
1.20 -#include "sqliteInt.h"
1.21 -
1.22 -/*
1.23 -** Look up every table that is named in pSrc. If any table is not found,
1.24 -** add an error message to pParse->zErrMsg and return NULL. If all tables
1.25 -** are found, return a pointer to the last table.
1.26 -*/
1.27 -Table *sqlite3SrcListLookup(Parse *pParse, SrcList *pSrc){
1.28 - Table *pTab = 0;
1.29 - int i;
1.30 - struct SrcList_item *pItem;
1.31 - for(i=0, pItem=pSrc->a; i<pSrc->nSrc; i++, pItem++){
1.32 - pTab = sqlite3LocateTable(pParse, pItem->zName, pItem->zDatabase);
1.33 - sqlite3DeleteTable(pItem->pTab);
1.34 - pItem->pTab = pTab;
1.35 - if( pTab ){
1.36 - pTab->nRef++;
1.37 - }
1.38 - }
1.39 - return pTab;
1.40 -}
1.41 -
1.42 -/*
1.43 -** Check to make sure the given table is writable. If it is not
1.44 -** writable, generate an error message and return 1. If it is
1.45 -** writable return 0;
1.46 -*/
1.47 -int sqlite3IsReadOnly(Parse *pParse, Table *pTab, int viewOk){
1.48 - if( (pTab->readOnly && (pParse->db->flags & SQLITE_WriteSchema)==0
1.49 - && pParse->nested==0)
1.50 -#ifndef SQLITE_OMIT_VIRTUALTABLE
1.51 - || (pTab->pMod && pTab->pMod->pModule->xUpdate==0)
1.52 -#endif
1.53 - ){
1.54 - sqlite3ErrorMsg(pParse, "table %s may not be modified", pTab->zName);
1.55 - return 1;
1.56 - }
1.57 -#ifndef SQLITE_OMIT_VIEW
1.58 - if( !viewOk && pTab->pSelect ){
1.59 - sqlite3ErrorMsg(pParse,"cannot modify %s because it is a view",pTab->zName);
1.60 - return 1;
1.61 - }
1.62 -#endif
1.63 - return 0;
1.64 -}
1.65 -
1.66 -/*
1.67 -** Generate code that will open a table for reading.
1.68 -*/
1.69 -void sqlite3OpenTable(
1.70 - Parse *p, /* Generate code into this VDBE */
1.71 - int iCur, /* The cursor number of the table */
1.72 - int iDb, /* The database index in sqlite3.aDb[] */
1.73 - Table *pTab, /* The table to be opened */
1.74 - int opcode /* OP_OpenRead or OP_OpenWrite */
1.75 -){
1.76 - Vdbe *v;
1.77 - if( IsVirtual(pTab) ) return;
1.78 - v = sqlite3GetVdbe(p);
1.79 - assert( opcode==OP_OpenWrite || opcode==OP_OpenRead );
1.80 - sqlite3TableLock(p, iDb, pTab->tnum, (opcode==OP_OpenWrite), pTab->zName);
1.81 - sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
1.82 - VdbeComment((v, "# %s", pTab->zName));
1.83 - sqlite3VdbeAddOp(v, opcode, iCur, pTab->tnum);
1.84 - sqlite3VdbeAddOp(v, OP_SetNumColumns, iCur, pTab->nCol);
1.85 -}
1.86 -
1.87 -
1.88 -/*
1.89 -** Generate code for a DELETE FROM statement.
1.90 -**
1.91 -** DELETE FROM table_wxyz WHERE a<5 AND b NOT NULL;
1.92 -** \________/ \________________/
1.93 -** pTabList pWhere
1.94 -*/
1.95 -void sqlite3DeleteFrom(
1.96 - Parse *pParse, /* The parser context */
1.97 - SrcList *pTabList, /* The table from which we should delete things */
1.98 - Expr *pWhere /* The WHERE clause. May be null */
1.99 -){
1.100 - Vdbe *v; /* The virtual database engine */
1.101 - Table *pTab; /* The table from which records will be deleted */
1.102 - const char *zDb; /* Name of database holding pTab */
1.103 - int end, addr = 0; /* A couple addresses of generated code */
1.104 - int i; /* Loop counter */
1.105 - WhereInfo *pWInfo; /* Information about the WHERE clause */
1.106 - Index *pIdx; /* For looping over indices of the table */
1.107 - int iCur; /* VDBE Cursor number for pTab */
1.108 - sqlite3 *db; /* Main database structure */
1.109 - AuthContext sContext; /* Authorization context */
1.110 - int oldIdx = -1; /* Cursor for the OLD table of AFTER triggers */
1.111 - NameContext sNC; /* Name context to resolve expressions in */
1.112 - int iDb; /* Database number */
1.113 - int memCnt = 0; /* Memory cell used for change counting */
1.114 -
1.115 -#ifndef SQLITE_OMIT_TRIGGER
1.116 - int isView; /* True if attempting to delete from a view */
1.117 - int triggers_exist = 0; /* True if any triggers exist */
1.118 -#endif
1.119 -
1.120 - sContext.pParse = 0;
1.121 - db = pParse->db;
1.122 - if( pParse->nErr || db->mallocFailed ){
1.123 - goto delete_from_cleanup;
1.124 - }
1.125 - assert( pTabList->nSrc==1 );
1.126 -
1.127 - /* Locate the table which we want to delete. This table has to be
1.128 - ** put in an SrcList structure because some of the subroutines we
1.129 - ** will be calling are designed to work with multiple tables and expect
1.130 - ** an SrcList* parameter instead of just a Table* parameter.
1.131 - */
1.132 - pTab = sqlite3SrcListLookup(pParse, pTabList);
1.133 - if( pTab==0 ) goto delete_from_cleanup;
1.134 -
1.135 - /* Figure out if we have any triggers and if the table being
1.136 - ** deleted from is a view
1.137 - */
1.138 -#ifndef SQLITE_OMIT_TRIGGER
1.139 - triggers_exist = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0);
1.140 - isView = pTab->pSelect!=0;
1.141 -#else
1.142 -# define triggers_exist 0
1.143 -# define isView 0
1.144 -#endif
1.145 -#ifdef SQLITE_OMIT_VIEW
1.146 -# undef isView
1.147 -# define isView 0
1.148 -#endif
1.149 -
1.150 - if( sqlite3IsReadOnly(pParse, pTab, triggers_exist) ){
1.151 - goto delete_from_cleanup;
1.152 - }
1.153 - iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
1.154 - assert( iDb<db->nDb );
1.155 - zDb = db->aDb[iDb].zName;
1.156 - if( sqlite3AuthCheck(pParse, SQLITE_DELETE, pTab->zName, 0, zDb) ){
1.157 - goto delete_from_cleanup;
1.158 - }
1.159 -
1.160 - /* If pTab is really a view, make sure it has been initialized.
1.161 - */
1.162 - if( sqlite3ViewGetColumnNames(pParse, pTab) ){
1.163 - goto delete_from_cleanup;
1.164 - }
1.165 -
1.166 - /* Allocate a cursor used to store the old.* data for a trigger.
1.167 - */
1.168 - if( triggers_exist ){
1.169 - oldIdx = pParse->nTab++;
1.170 - }
1.171 -
1.172 - /* Resolve the column names in the WHERE clause.
1.173 - */
1.174 - assert( pTabList->nSrc==1 );
1.175 - iCur = pTabList->a[0].iCursor = pParse->nTab++;
1.176 - memset(&sNC, 0, sizeof(sNC));
1.177 - sNC.pParse = pParse;
1.178 - sNC.pSrcList = pTabList;
1.179 - if( sqlite3ExprResolveNames(&sNC, pWhere) ){
1.180 - goto delete_from_cleanup;
1.181 - }
1.182 -
1.183 - /* Start the view context
1.184 - */
1.185 - if( isView ){
1.186 - sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
1.187 - }
1.188 -
1.189 - /* Begin generating code.
1.190 - */
1.191 - v = sqlite3GetVdbe(pParse);
1.192 - if( v==0 ){
1.193 - goto delete_from_cleanup;
1.194 - }
1.195 - if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
1.196 - sqlite3BeginWriteOperation(pParse, triggers_exist, iDb);
1.197 -
1.198 - /* If we are trying to delete from a view, realize that view into
1.199 - ** a ephemeral table.
1.200 - */
1.201 - if( isView ){
1.202 - Select *pView = sqlite3SelectDup(db, pTab->pSelect);
1.203 - sqlite3Select(pParse, pView, SRT_EphemTab, iCur, 0, 0, 0, 0);
1.204 - sqlite3SelectDelete(pView);
1.205 - }
1.206 -
1.207 - /* Initialize the counter of the number of rows deleted, if
1.208 - ** we are counting rows.
1.209 - */
1.210 - if( db->flags & SQLITE_CountRows ){
1.211 - memCnt = pParse->nMem++;
1.212 - sqlite3VdbeAddOp(v, OP_MemInt, 0, memCnt);
1.213 - }
1.214 -
1.215 - /* Special case: A DELETE without a WHERE clause deletes everything.
1.216 - ** It is easier just to erase the whole table. Note, however, that
1.217 - ** this means that the row change count will be incorrect.
1.218 - */
1.219 - if( pWhere==0 && !triggers_exist && !IsVirtual(pTab) ){
1.220 - if( db->flags & SQLITE_CountRows ){
1.221 - /* If counting rows deleted, just count the total number of
1.222 - ** entries in the table. */
1.223 - int endOfLoop = sqlite3VdbeMakeLabel(v);
1.224 - int addr2;
1.225 - if( !isView ){
1.226 - sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenRead);
1.227 - }
1.228 - sqlite3VdbeAddOp(v, OP_Rewind, iCur, sqlite3VdbeCurrentAddr(v)+2);
1.229 - addr2 = sqlite3VdbeAddOp(v, OP_MemIncr, 1, memCnt);
1.230 - sqlite3VdbeAddOp(v, OP_Next, iCur, addr2);
1.231 - sqlite3VdbeResolveLabel(v, endOfLoop);
1.232 - sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
1.233 - }
1.234 - if( !isView ){
1.235 - sqlite3VdbeAddOp(v, OP_Clear, pTab->tnum, iDb);
1.236 - if( !pParse->nested ){
1.237 - sqlite3VdbeChangeP3(v, -1, pTab->zName, P3_STATIC);
1.238 - }
1.239 - for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
1.240 - assert( pIdx->pSchema==pTab->pSchema );
1.241 - sqlite3VdbeAddOp(v, OP_Clear, pIdx->tnum, iDb);
1.242 - }
1.243 - }
1.244 - }
1.245 - /* The usual case: There is a WHERE clause so we have to scan through
1.246 - ** the table and pick which records to delete.
1.247 - */
1.248 - else{
1.249 - /* Begin the database scan
1.250 - */
1.251 - pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0);
1.252 - if( pWInfo==0 ) goto delete_from_cleanup;
1.253 -
1.254 - /* Remember the rowid of every item to be deleted.
1.255 - */
1.256 - sqlite3VdbeAddOp(v, IsVirtual(pTab) ? OP_VRowid : OP_Rowid, iCur, 0);
1.257 - sqlite3VdbeAddOp(v, OP_FifoWrite, 0, 0);
1.258 - if( db->flags & SQLITE_CountRows ){
1.259 - sqlite3VdbeAddOp(v, OP_MemIncr, 1, memCnt);
1.260 - }
1.261 -
1.262 - /* End the database scan loop.
1.263 - */
1.264 - sqlite3WhereEnd(pWInfo);
1.265 -
1.266 - /* Open the pseudo-table used to store OLD if there are triggers.
1.267 - */
1.268 - if( triggers_exist ){
1.269 - sqlite3VdbeAddOp(v, OP_OpenPseudo, oldIdx, 0);
1.270 - sqlite3VdbeAddOp(v, OP_SetNumColumns, oldIdx, pTab->nCol);
1.271 - }
1.272 -
1.273 - /* Delete every item whose key was written to the list during the
1.274 - ** database scan. We have to delete items after the scan is complete
1.275 - ** because deleting an item can change the scan order.
1.276 - */
1.277 - end = sqlite3VdbeMakeLabel(v);
1.278 -
1.279 - /* This is the beginning of the delete loop when there are
1.280 - ** row triggers.
1.281 - */
1.282 - if( triggers_exist ){
1.283 - addr = sqlite3VdbeAddOp(v, OP_FifoRead, 0, end);
1.284 - if( !isView ){
1.285 - sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
1.286 - sqlite3OpenTable(pParse, iCur, iDb, pTab, OP_OpenRead);
1.287 - }
1.288 - sqlite3VdbeAddOp(v, OP_MoveGe, iCur, 0);
1.289 - sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0);
1.290 - sqlite3VdbeAddOp(v, OP_RowData, iCur, 0);
1.291 - sqlite3VdbeAddOp(v, OP_Insert, oldIdx, 0);
1.292 - if( !isView ){
1.293 - sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
1.294 - }
1.295 -
1.296 - (void)sqlite3CodeRowTrigger(pParse, TK_DELETE, 0, TRIGGER_BEFORE, pTab,
1.297 - -1, oldIdx, (pParse->trigStack)?pParse->trigStack->orconf:OE_Default,
1.298 - addr);
1.299 - }
1.300 -
1.301 - if( !isView ){
1.302 - /* Open cursors for the table we are deleting from and all its
1.303 - ** indices. If there are row triggers, this happens inside the
1.304 - ** OP_FifoRead loop because the cursor have to all be closed
1.305 - ** before the trigger fires. If there are no row triggers, the
1.306 - ** cursors are opened only once on the outside the loop.
1.307 - */
1.308 - sqlite3OpenTableAndIndices(pParse, pTab, iCur, OP_OpenWrite);
1.309 -
1.310 - /* This is the beginning of the delete loop when there are no
1.311 - ** row triggers */
1.312 - if( !triggers_exist ){
1.313 - addr = sqlite3VdbeAddOp(v, OP_FifoRead, 0, end);
1.314 - }
1.315 -
1.316 - /* Delete the row */
1.317 -#ifndef SQLITE_OMIT_VIRTUALTABLE
1.318 - if( IsVirtual(pTab) ){
1.319 - pParse->pVirtualLock = pTab;
1.320 - sqlite3VdbeOp3(v, OP_VUpdate, 0, 1, (const char*)pTab->pVtab, P3_VTAB);
1.321 - }else
1.322 -#endif
1.323 - {
1.324 - sqlite3GenerateRowDelete(db, v, pTab, iCur, pParse->nested==0);
1.325 - }
1.326 - }
1.327 -
1.328 - /* If there are row triggers, close all cursors then invoke
1.329 - ** the AFTER triggers
1.330 - */
1.331 - if( triggers_exist ){
1.332 - if( !isView ){
1.333 - for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
1.334 - sqlite3VdbeAddOp(v, OP_Close, iCur + i, pIdx->tnum);
1.335 - }
1.336 - sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
1.337 - }
1.338 - (void)sqlite3CodeRowTrigger(pParse, TK_DELETE, 0, TRIGGER_AFTER, pTab, -1,
1.339 - oldIdx, (pParse->trigStack)?pParse->trigStack->orconf:OE_Default,
1.340 - addr);
1.341 - }
1.342 -
1.343 - /* End of the delete loop */
1.344 - sqlite3VdbeAddOp(v, OP_Goto, 0, addr);
1.345 - sqlite3VdbeResolveLabel(v, end);
1.346 -
1.347 - /* Close the cursors after the loop if there are no row triggers */
1.348 - if( !triggers_exist && !IsVirtual(pTab) ){
1.349 - for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
1.350 - sqlite3VdbeAddOp(v, OP_Close, iCur + i, pIdx->tnum);
1.351 - }
1.352 - sqlite3VdbeAddOp(v, OP_Close, iCur, 0);
1.353 - }
1.354 - }
1.355 -
1.356 - /*
1.357 - ** Return the number of rows that were deleted. If this routine is
1.358 - ** generating code because of a call to sqlite3NestedParse(), do not
1.359 - ** invoke the callback function.
1.360 - */
1.361 - if( db->flags & SQLITE_CountRows && pParse->nested==0 && !pParse->trigStack ){
1.362 - sqlite3VdbeAddOp(v, OP_MemLoad, memCnt, 0);
1.363 - sqlite3VdbeAddOp(v, OP_Callback, 1, 0);
1.364 - sqlite3VdbeSetNumCols(v, 1);
1.365 - sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows deleted", P3_STATIC);
1.366 - }
1.367 -
1.368 -delete_from_cleanup:
1.369 - sqlite3AuthContextPop(&sContext);
1.370 - sqlite3SrcListDelete(pTabList);
1.371 - sqlite3ExprDelete(pWhere);
1.372 - return;
1.373 -}
1.374 -
1.375 -/*
1.376 -** This routine generates VDBE code that causes a single row of a
1.377 -** single table to be deleted.
1.378 -**
1.379 -** The VDBE must be in a particular state when this routine is called.
1.380 -** These are the requirements:
1.381 -**
1.382 -** 1. A read/write cursor pointing to pTab, the table containing the row
1.383 -** to be deleted, must be opened as cursor number "base".
1.384 -**
1.385 -** 2. Read/write cursors for all indices of pTab must be open as
1.386 -** cursor number base+i for the i-th index.
1.387 -**
1.388 -** 3. The record number of the row to be deleted must be on the top
1.389 -** of the stack.
1.390 -**
1.391 -** This routine pops the top of the stack to remove the record number
1.392 -** and then generates code to remove both the table record and all index
1.393 -** entries that point to that record.
1.394 -*/
1.395 -void sqlite3GenerateRowDelete(
1.396 - sqlite3 *db, /* The database containing the index */
1.397 - Vdbe *v, /* Generate code into this VDBE */
1.398 - Table *pTab, /* Table containing the row to be deleted */
1.399 - int iCur, /* Cursor number for the table */
1.400 - int count /* Increment the row change counter */
1.401 -){
1.402 - int addr;
1.403 - addr = sqlite3VdbeAddOp(v, OP_NotExists, iCur, 0);
1.404 - sqlite3GenerateRowIndexDelete(v, pTab, iCur, 0);
1.405 - sqlite3VdbeAddOp(v, OP_Delete, iCur, (count?OPFLAG_NCHANGE:0));
1.406 - if( count ){
1.407 - sqlite3VdbeChangeP3(v, -1, pTab->zName, P3_STATIC);
1.408 - }
1.409 - sqlite3VdbeJumpHere(v, addr);
1.410 -}
1.411 -
1.412 -/*
1.413 -** This routine generates VDBE code that causes the deletion of all
1.414 -** index entries associated with a single row of a single table.
1.415 -**
1.416 -** The VDBE must be in a particular state when this routine is called.
1.417 -** These are the requirements:
1.418 -**
1.419 -** 1. A read/write cursor pointing to pTab, the table containing the row
1.420 -** to be deleted, must be opened as cursor number "iCur".
1.421 -**
1.422 -** 2. Read/write cursors for all indices of pTab must be open as
1.423 -** cursor number iCur+i for the i-th index.
1.424 -**
1.425 -** 3. The "iCur" cursor must be pointing to the row that is to be
1.426 -** deleted.
1.427 -*/
1.428 -void sqlite3GenerateRowIndexDelete(
1.429 - Vdbe *v, /* Generate code into this VDBE */
1.430 - Table *pTab, /* Table containing the row to be deleted */
1.431 - int iCur, /* Cursor number for the table */
1.432 - char *aIdxUsed /* Only delete if aIdxUsed!=0 && aIdxUsed[i]!=0 */
1.433 -){
1.434 - int i;
1.435 - Index *pIdx;
1.436 -
1.437 - for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
1.438 - if( aIdxUsed!=0 && aIdxUsed[i-1]==0 ) continue;
1.439 - sqlite3GenerateIndexKey(v, pIdx, iCur);
1.440 - sqlite3VdbeAddOp(v, OP_IdxDelete, iCur+i, 0);
1.441 - }
1.442 -}
1.443 -
1.444 -/*
1.445 -** Generate code that will assemble an index key and put it on the top
1.446 -** of the tack. The key with be for index pIdx which is an index on pTab.
1.447 -** iCur is the index of a cursor open on the pTab table and pointing to
1.448 -** the entry that needs indexing.
1.449 -*/
1.450 -void sqlite3GenerateIndexKey(
1.451 - Vdbe *v, /* Generate code into this VDBE */
1.452 - Index *pIdx, /* The index for which to generate a key */
1.453 - int iCur /* Cursor number for the pIdx->pTable table */
1.454 -){
1.455 - int j;
1.456 - Table *pTab = pIdx->pTable;
1.457 -
1.458 - sqlite3VdbeAddOp(v, OP_Rowid, iCur, 0);
1.459 - for(j=0; j<pIdx->nColumn; j++){
1.460 - int idx = pIdx->aiColumn[j];
1.461 - if( idx==pTab->iPKey ){
1.462 - sqlite3VdbeAddOp(v, OP_Dup, j, 0);
1.463 - }else{
1.464 - sqlite3VdbeAddOp(v, OP_Column, iCur, idx);
1.465 - sqlite3ColumnDefault(v, pTab, idx);
1.466 - }
1.467 - }
1.468 - sqlite3VdbeAddOp(v, OP_MakeIdxRec, pIdx->nColumn, 0);
1.469 - sqlite3IndexAffinityStr(v, pIdx);
1.470 -}
