diff options
Diffstat (limited to 'src/delete.c')
| -rw-r--r-- | src/delete.c | 153 |
1 files changed, 87 insertions, 66 deletions
diff --git a/src/delete.c b/src/delete.c index ae4a8b584..f0ca8ab47 100644 --- a/src/delete.c +++ b/src/delete.c @@ -338,9 +338,9 @@ void sqlite3DeleteFrom( #ifndef SQLITE_OMIT_TRUNCATE_OPTIMIZATION /* Special case: A DELETE without a WHERE clause deletes everything. - ** It is easier just to erase the whole table. Note, however, that - ** this means that the row change count will be incorrect. - */ + ** 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. */ if( rcauth==SQLITE_OK && pWhere==0 && !pTrigger && !IsVirtual(pTab) ){ assert( !isView ); sqlite3VdbeAddOp4(v, OP_Clear, pTab->tnum, iDb, memCnt, @@ -357,7 +357,6 @@ void sqlite3DeleteFrom( { int iRowSet = ++pParse->nMem; /* Register for rowset of rows to delete */ int iRowid = ++pParse->nMem; /* Used for storing rowid values. */ - int regOld = pParse->nMem + 1; /* Start of array for old.* (if triggers) */ int regRowid; /* Actual register containing rowids */ /* Collect rowids of every row to be deleted. @@ -387,56 +386,19 @@ void sqlite3DeleteFrom( addr = sqlite3VdbeAddOp3(v, OP_RowSetRead, iRowSet, end, iRowid); - /* If there are triggers, populate an array of registers with the - ** data required by the old.* references in the trigger bodies. */ - if( pTrigger ){ - u32 mask = 0; /* Mask of OLD.* columns in use */ - pParse->nMem += pTab->nCol; - - /* Open the pseudo-table used to store OLD if there are triggers. */ - mask = sqlite3TriggerOldmask( - pParse, pTrigger, TK_DELETE, 0, pTab, OE_Default); - - /* If the record is no longer present in the table, jump to the - ** next iteration of the loop through the contents of the fifo. - */ - sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, iRowid); - - /* Populate the OLD.* pseudo-table */ - assert( regOld==iRowid+1 ); - for(i=0; i<pTab->nCol; i++){ - if( mask==0xffffffff || mask&(1<<i) ){ - sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regOld+i); - sqlite3ColumnDefault(v, pTab, i, regOld+i); - } - } - sqlite3VdbeAddOp2(v, OP_Affinity, regOld, pTab->nCol); - sqlite3TableAffinityStr(v, pTab); - - sqlite3CodeRowTrigger(pParse, pTrigger, - TK_DELETE, 0, TRIGGER_BEFORE, pTab, -1, iRowid, OE_Default, addr - ); - } - - if( !isView ){ - /* Delete the row */ + /* Delete the row */ #ifndef SQLITE_OMIT_VIRTUALTABLE - if( IsVirtual(pTab) ){ - const char *pVTab = (const char *)sqlite3GetVTable(db, pTab); - sqlite3VtabMakeWritable(pParse, pTab); - sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iRowid, pVTab, P4_VTAB); - }else + if( IsVirtual(pTab) ){ + const char *pVTab = (const char *)sqlite3GetVTable(db, pTab); + sqlite3VtabMakeWritable(pParse, pTab); + sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iRowid, pVTab, P4_VTAB); + }else #endif - { - sqlite3GenerateRowDelete(pParse, pTab, iCur, iRowid, pParse->nested==0); - } + { + int count = (pParse->nested==0); /* True to count changes */ + sqlite3GenerateRowDelete(pParse, pTab, iCur, iRowid, count, pTrigger, OE_Default); } - /* Code the AFTER triggers. This is a no-op if there are no triggers. */ - sqlite3CodeRowTrigger(pParse, - pTrigger, TK_DELETE, 0, TRIGGER_AFTER, pTab, -1, iRowid, OE_Default, addr - ); - /* End of the delete loop */ sqlite3VdbeAddOp2(v, OP_Goto, 0, addr); sqlite3VdbeResolveLabel(v, end); @@ -458,8 +420,7 @@ void sqlite3DeleteFrom( sqlite3AutoincrementEnd(pParse); } - /* - ** Return the number of rows that were deleted. If this routine is + /* 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. */ @@ -492,28 +453,88 @@ delete_from_cleanup: ** 3. The record number of the row to be deleted must be stored in ** memory cell iRowid. ** -** This routine pops the top of the stack to remove the record number -** and then generates code to remove both the table record and all index -** entries that point to that record. +** This routine generates code to remove both the table record and all +** index entries that point to that record. */ void sqlite3GenerateRowDelete( Parse *pParse, /* Parsing context */ Table *pTab, /* Table containing the row to be deleted */ int iCur, /* Cursor number for the table */ int iRowid, /* Memory cell that contains the rowid to delete */ - int count /* Increment the row change counter */ + int count, /* If non-zero, increment the row change counter */ + Trigger *pTrigger, /* List of triggers to (potentially) fire */ + int onconf /* Default ON CONFLICT policy for triggers */ ){ - int addr; - Vdbe *v; - - v = pParse->pVdbe; - addr = sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, iRowid); - sqlite3GenerateRowIndexDelete(pParse, pTab, iCur, 0); - sqlite3VdbeAddOp2(v, OP_Delete, iCur, (count?OPFLAG_NCHANGE:0)); - if( count ){ - sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_STATIC); + Vdbe *v = pParse->pVdbe; /* Vdbe */ + int iOld; /* First register in OLD.* array */ + int iLabel; /* Label resolved to end of generated code */ + + /* Vdbe is guaranteed to have been allocated by this stage. */ + assert( v ); + + /* 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(v); + sqlite3VdbeAddOp3(v, OP_NotExists, iCur, iLabel, iRowid); + + /* If there are any triggers to fire, allocate a range of registers to + ** use for the old.* references in the triggers. */ + if( pTrigger ){ + u32 mask; /* Mask of OLD.* columns in use */ + int iCol; /* Iterator used while populating OLD.* */ + + /* TODO: Could use temporary registers here. Also could attempt to + ** avoid copying the contents of the rowid register. */ + mask = sqlite3TriggerOldmask(pParse, pTrigger, TK_DELETE, 0, pTab, onconf); + 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, iRowid, iOld); + for(iCol=0; iCol<pTab->nCol; iCol++){ + if( mask==0xffffffff || mask&(1<<iCol) ){ + int iTarget = iOld + iCol + 1; + sqlite3VdbeAddOp3(v, OP_Column, iCur, iCol, iTarget); + sqlite3ColumnDefault(v, pTab, iCol, iTarget); + } + } + + /* Invoke any BEFORE trigger programs */ + sqlite3CodeRowTrigger(pParse, pTrigger, + TK_DELETE, 0, TRIGGER_BEFORE, pTab, -1, iOld, onconf, iLabel + ); + + /* Seek the cursor to the row to be deleted again. It may be that + ** the BEFORE triggers coded above have already removed the row + ** being deleted. Do not attempt to delete the row a second time, and + ** do not fire AFTER triggers. */ + sqlite3VdbeAddOp3(v, OP_NotExists, iCur, iLabel, iRowid); + } + + /* 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( pTab->pSelect==0 ){ + sqlite3GenerateRowIndexDelete(pParse, pTab, iCur, 0); + sqlite3VdbeAddOp2(v, OP_Delete, iCur, (count?OPFLAG_NCHANGE:0)); + if( count ){ + sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_STATIC); + } } - sqlite3VdbeJumpHere(v, addr); + + /* Invoke AFTER triggers. */ + if( pTrigger ){ + sqlite3CodeRowTrigger(pParse, pTrigger, + TK_DELETE, 0, TRIGGER_AFTER, pTab, -1, 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); } /* |