/*
** 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 addrTop = 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 */
Index *pPk; /* The PRIMARY KEY index for WITHOUT ROWID tables */
int nIdx; /* Number of indices that need updating */
int iBaseCur; /* Base cursor number */
int iDataCur; /* Cursor for the canonical data btree */
int iIdxCur; /* Cursor for the first index */
sqlite3 *db; /* The database structure */
int *aRegIdx = 0; /* One register assigned to each index to be updated */
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. */
u8 *aToOpen; /* 1 for tables and indices to be opened */
u8 chngPk; /* PRIMARY KEY changed in a WITHOUT ROWID table */
u8 chngRowid; /* Rowid changed in a normal table */
u8 chngKey; /* Either chngPk or chngRowid */
Expr *pRowidExpr = 0; /* Expression defining the new record number */
AuthContext sContext; /* The authorization context */
NameContext sNC; /* The name-context to resolve expressions in */
int iDb; /* Database containing the table being updated */
int okOnePass; /* True for one-pass algorithm without the FIFO */
int hasFK; /* True if foreign key processing is required */
int labelBreak; /* Jump here to break out of UPDATE loop */
int labelContinue; /* Jump here to continue next step of UPDATE loop */
#ifndef SQLITE_OMIT_TRIGGER
int isView; /* True when updating a view (INSTEAD OF trigger) */
Trigger *pTrigger; /* List of triggers on pTab, if required */
int tmask; /* Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
#endif
int newmask; /* Mask of NEW.* columns accessed by BEFORE triggers */
int iEph = 0; /* Ephemeral table holding all primary key values */
int nKey = 0; /* Number of elements in regKey for WITHOUT ROWID */
int aiCurOnePass[2]; /* The write cursors opened by WHERE_ONEPASS */
/* Register Allocations */
int regRowCount = 0; /* A count of rows changed */
int regOldRowid = 0; /* The old rowid */
int regNewRowid = 0; /* The new rowid */
int regNew = 0; /* Content of the NEW.* table in triggers */
int regOld = 0; /* Content of OLD.* table in triggers */
int regRowSet = 0; /* Rowset of rows to be updated */
int regKey = 0; /* composite PRIMARY KEY value */
memset(&sContext, 0, sizeof(sContext));
db = pParse->db;
if( pParse->nErr || db->mallocFailed ){
goto update_cleanup;
}
assert( pTabList->nSrc==1 );
/* Locate the table which we want to update.
*/
pTab = sqlite3SrcListLookup(pParse, pTabList);
if( pTab==0 ) goto update_cleanup;
iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
/* Figure out if we have any triggers and if the table being
** updated is a view.
*/
#ifndef SQLITE_OMIT_TRIGGER
pTrigger = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges, &tmask);
isView = pTab->pSelect!=0;
assert( pTrigger || tmask==0 );
#else
# define pTrigger 0
# define isView 0
# define tmask 0
#endif
#ifdef SQLITE_OMIT_VIEW
# undef isView
# define isView 0
#endif
if( sqlite3ViewGetColumnNames(pParse, pTab) ){
goto update_cleanup;
}
if( sqlite3IsReadOnly(pParse, pTab, tmask) ){
goto update_cleanup;
}
/* 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 = iBaseCur = iDataCur = pParse->nTab++;
iIdxCur = iDataCur+1;
pPk = HasRowid(pTab) ? 0 : sqlite3PrimaryKeyIndex(pTab);
for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){
if( IsPrimaryKeyIndex(pIdx) && pPk!=0 ){
iDataCur = pParse->nTab;
pTabList->a[0].iCursor = iDataCur;
}
pParse->nTab++;
}
/* Allocate space for aXRef[], aRegIdx[], and aToOpen[].
** Initialize aXRef[] and aToOpen[] to their default values.
*/
aXRef = sqlite3DbMallocRaw(db, sizeof(int) * (pTab->nCol+nIdx) + nIdx+2 );
if( aXRef==0 ) goto update_cleanup;
aRegIdx = aXRef+pTab->nCol;
aToOpen = (u8*)(aRegIdx+nIdx);
memset(aToOpen, 1, nIdx+1);
aToOpen[nIdx+1] = 0;
for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;
/* 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 = chngPk = 0;
for(i=0; i<pChanges->nExpr; i++){
if( sqlite3ResolveExprNames(&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;
}else if( pPk && (pTab->aCol[j].colFlags & COLFLAG_PRIMKEY)!=0 ){
chngPk = 1;
}
aXRef[j] = i;
break;
}
}
if( j>=pTab->nCol ){
if( pPk==0 && sqlite3IsRowid(pChanges->a[i].zName) ){
j = -1;
chngRowid = 1;
pRowidExpr = pChanges->a[i].pExpr;
}else{
sqlite3ErrorMsg(pParse, "no such column: %s", pChanges->a[i].zName);
pParse->checkSchema = 1;
goto update_cleanup;
}
}
#ifndef SQLITE_OMIT_AUTHORIZATION
{
int rc;
rc = sqlite3AuthCheck(pParse, SQLITE_UPDATE, pTab->zName,
j<0 ? "ROWID" : pTab->aCol[j].zName,
db->aDb[iDb].zName);
if( rc==SQLITE_DENY ){
goto update_cleanup;
}else if( rc==SQLITE_IGNORE ){
aXRef[j] = -1;
}
}
#endif
}
assert( (chngRowid & chngPk)==0 );
assert( chngRowid==0 || chngRowid==1 );
assert( chngPk==0 || chngPk==1 );
chngKey = chngRowid + chngPk;
/* The SET expressions are not actually used inside the WHERE loop.
** So reset the colUsed mask
*/
pTabList->a[0].colUsed = 0;
hasFK = sqlite3FkRequired(pParse, pTab, aXRef, chngKey);
/* There is one entry in the aRegIdx[] array for each index on the table
** being updated. Fill in aRegIdx[] with a register number that will hold
** the key for accessing each index.
**
** FIXME: Be smarter about omitting indexes that use expressions.
*/
for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
int reg;
if( chngKey || hasFK || pIdx->pPartIdxWhere || pIdx==pPk ){
reg = ++pParse->nMem;
}else{
reg = 0;
for(i=0; i<pIdx->nKeyCol; i++){
i16 iIdxCol = pIdx->aiColumn[i];
if( iIdxCol<0 || aXRef[iIdxCol]>=0 ){
reg = ++pParse->nMem;
break;
}
}
}
if( reg==0 ) aToOpen[j+1] = 0;
aRegIdx[j] = reg;
}
/* Begin generating code. */
v = sqlite3GetVdbe(pParse);
if( v==0 ) goto update_cleanup;
if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
sqlite3BeginWriteOperation(pParse, 1, iDb);
/* Allocate required registers. */
if( !IsVirtual(pTab) ){
regRowSet = ++pParse->nMem;
regOldRowid = regNewRowid = ++pParse->nMem;
if( chngPk || pTrigger || hasFK ){
regOld = pParse->nMem + 1;
pParse->nMem += pTab->nCol;
}
if( chngKey || pTrigger || hasFK ){
regNewRowid = ++pParse->nMem;
}
regNew = pParse->nMem + 1;
pParse->nMem += pTab->nCol;
}
/* Start the view context. */
if( isView ){
sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
}
/* If we are trying to update a view, realize that view into
** an ephemeral table.
*/
#if !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER)
if( isView ){
sqlite3MaterializeView(pParse, pTab, pWhere, iDataCur);
}
#endif
/* Resolve the column names in all the expressions in the
** WHERE clause.
*/
if( sqlite3ResolveExprNames(&sNC, pWhere) ){
goto update_cleanup;
}
#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Virtual tables must be handled separately */
if( IsVirtual(pTab) ){
updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
pWhere, onError);
goto update_cleanup;
}
#endif
/* Begin the database scan
*/
if( HasRowid(pTab) ){
sqlite3VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldRowid);
pWInfo = sqlite3WhereBegin(
pParse, pTabList, pWhere, 0, 0, WHERE_ONEPASS_DESIRED, iIdxCur
);
if( pWInfo==0 ) goto update_cleanup;
okOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
/* Remember the rowid of every item to be updated.
*/
sqlite3VdbeAddOp2(v, OP_Rowid, iDataCur, regOldRowid);
if( !okOnePass ){
sqlite3VdbeAddOp2(v, OP_RowSetAdd, regRowSet, regOldRowid);
}
/* End the database scan loop.
*/
sqlite3WhereEnd(pWInfo);
}else{
int iPk; /* First of nPk memory cells holding PRIMARY KEY value */
i16 nPk; /* Number of components of the PRIMARY KEY */
int addrOpen; /* Address of the OpenEphemeral instruction */
assert( pPk!=0 );
nPk = pPk->nKeyCol;
iPk = pParse->nMem+1;
pParse->nMem += nPk;
regKey = ++pParse->nMem;
iEph = pParse->nTab++;
sqlite3VdbeAddOp2(v, OP_Null, 0, iPk);
addrOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEph, nPk);
sqlite3VdbeSetP4KeyInfo(pParse, pPk);
pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0,
WHERE_ONEPASS_DESIRED, iIdxCur);
if( pWInfo==0 ) goto update_cleanup;
okOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
for(i=0; i<nPk; i++){
assert( pPk->aiColumn[i]>=0 );
sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, pPk->aiColumn[i],
iPk+i);
}
if( okOnePass ){
sqlite3VdbeChangeToNoop(v, addrOpen);
nKey = nPk;
regKey = iPk;
}else{
sqlite3VdbeAddOp4(v, OP_MakeRecord, iPk, nPk, regKey,
sqlite3IndexAffinityStr(db, pPk), nPk);
sqlite3VdbeAddOp2(v, OP_IdxInsert, iEph, regKey);
}
sqlite3WhereEnd(pWInfo);
}
/* Initialize the count of updated rows
*/
if( (db->flags & SQLITE_CountRows) && !pParse->pTriggerTab ){
regRowCount = ++pParse->nMem;
sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
}
labelBreak = sqlite3VdbeMakeLabel(v);
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.
*/
if( onError==OE_Replace ){
memset(aToOpen, 1, nIdx+1);
}else{
for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
if( pIdx->onError==OE_Replace ){
memset(aToOpen, 1, nIdx+1);
break;
}
}
}
if( okOnePass ){
if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iBaseCur] = 0;
if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iBaseCur] = 0;
}
sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, 0, iBaseCur, aToOpen,
0, 0);
}
/* Top of the update loop */
if( okOnePass ){
if( aToOpen[iDataCur-iBaseCur] && !isView ){
assert( pPk );
sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelBreak, regKey, nKey);
VdbeCoverageNeverTaken(v);
}
labelContinue = labelBreak;
sqlite3VdbeAddOp2(v, OP_IsNull, pPk ? regKey : regOldRowid, labelBreak);
VdbeCoverageIf(v, pPk==0);
VdbeCoverageIf(v, pPk!=0);
}else if( pPk ){
labelContinue = sqlite3VdbeMakeLabel(v);
sqlite3VdbeAddOp2(v, OP_Rewind, iEph, labelBreak); VdbeCoverage(v);
addrTop = sqlite3VdbeAddOp2(v, OP_RowKey, iEph, regKey);
sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelContinue, regKey, 0);
VdbeCoverage(v);
}else{
labelContinue = sqlite3VdbeAddOp3(v, OP_RowSetRead, regRowSet, labelBreak,
regOldRowid);
VdbeCoverage(v);
sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, labelContinue, regOldRowid);
VdbeCoverage(v);
}
/* If the record number will change, set register regNewRowid to
** contain the new value. If the record number is not being modified,
** then regNewRowid is the same register as regOldRowid, which is
** already populated. */
assert( chngKey || pTrigger || hasFK || regOldRowid==regNewRowid );
if( chngRowid ){
sqlite3ExprCode(pParse, pRowidExpr, regNewRowid);
sqlite3VdbeAddOp1(v, OP_MustBeInt, regNewRowid); VdbeCoverage(v);
}
/* Compute the old pre-UPDATE content of the row being changed, if that
** information is needed */
if( chngPk || hasFK || pTrigger ){
u32 oldmask = (hasFK ? sqlite3FkOldmask(pParse, pTab) : 0);
oldmask |= sqlite3TriggerColmask(pParse,
pTrigger, pChanges, 0, TRIGGER_BEFORE|TRIGGER_AFTER, pTab, onError
);
for(i=0; i<pTab->nCol; i++){
if( oldmask==0xffffffff
|| (i<32 && (oldmask & MASKBIT32(i))!=0)
|| (pTab->aCol[i].colFlags & COLFLAG_PRIMKEY)!=0
){
testcase( oldmask!=0xffffffff && i==31 );
sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, regOld+i);
}else{
sqlite3VdbeAddOp2(v, OP_Null, 0, regOld+i);
}
}
if( chngRowid==0 && pPk==0 ){
sqlite3VdbeAddOp2(v, OP_Copy, regOldRowid, regNewRowid);
}
}
/* Populate the array of registers beginning at regNew with the new
** row data. This array is used to check constants, create the new
** table and index records, and as the values for any new.* references
** made by triggers.
**
** If there are one or more BEFORE triggers, then do not populate the
** registers associated with columns that are (a) not modified by
** this UPDATE statement and (b) not accessed by new.* references. The
** values for registers not modified by the UPDATE must be reloaded from
** the database after the BEFORE triggers are fired anyway (as the trigger
** may have modified them). So not loading those that are not going to
** be used eliminates some redundant opcodes.
*/
newmask = sqlite3TriggerColmask(
pParse, pTrigger, pChanges, 1, TRIGGER_BEFORE, pTab, onError
);
for(i=0; i<pTab->nCol; i++){
if( i==pTab->iPKey ){
sqlite3VdbeAddOp2(v, OP_Null, 0, regNew+i);
}else{
j = aXRef[i];
if( j>=0 ){
sqlite3ExprCode(pParse, pChanges->a[j].pExpr, regNew+i);
}else if( 0==(tmask&TRIGGER_BEFORE) || i>31 || (newmask & MASKBIT32(i)) ){
/* This branch loads the value of a column that will not be changed
** into a register. This is done if there are no BEFORE triggers, or
** if there are one or more BEFORE triggers that use this value via
** a new.* reference in a trigger program.
*/
testcase( i==31 );
testcase( i==32 );
sqlite3ExprCodeGetColumnToReg(pParse, pTab, i, iDataCur, regNew+i);
}else{
sqlite3VdbeAddOp2(v, OP_Null, 0, regNew+i);
}
}
}
/* Fire any BEFORE UPDATE triggers. This happens before constraints are
** verified. One could argue that this is wrong.
*/
if( tmask&TRIGGER_BEFORE ){
sqlite3TableAffinity(v, pTab, regNew);
sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges,
TRIGGER_BEFORE, pTab, regOldRowid, onError, labelContinue);
/* The row-trigger may have deleted the row being updated. In this
** case, jump to the next row. No updates or AFTER triggers are
** required. This behavior - what happens when the row being updated
** is deleted or renamed by a BEFORE trigger - is left undefined in the
** documentation.
*/
if( pPk ){
sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelContinue,regKey,nKey);
VdbeCoverage(v);
}else{
sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, labelContinue, regOldRowid);
VdbeCoverage(v);
}
/* If it did not delete it, the row-trigger may still have modified
** some of the columns of the row being updated. Load the values for
** all columns not modified by the update statement into their
** registers in case this has happened.
*/
for(i=0; i<pTab->nCol; i++){
if( aXRef[i]<0 && i!=pTab->iPKey ){
sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, regNew+i);
}
}
}
if( !isView ){
int addr1 = 0; /* Address of jump instruction */
int bReplace = 0; /* True if REPLACE conflict resolution might happen */
/* Do constraint checks. */
assert( regOldRowid>0 );
sqlite3GenerateConstraintChecks(pParse, pTab, aRegIdx, iDataCur, iIdxCur,
regNewRowid, regOldRowid, chngKey, onError, labelContinue, &bReplace);
/* Do FK constraint checks. */
if( hasFK ){
sqlite3FkCheck(pParse, pTab, regOldRowid, 0, aXRef, chngKey);
}
/* Delete the index entries associated with the current record. */
if( bReplace || chngKey ){
if( pPk ){
addr1 = sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, 0, regKey, nKey);
}else{
addr1 = sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, 0, regOldRowid);
}
VdbeCoverageNeverTaken(v);
}
sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur, aRegIdx, -1);
/* If changing the record number, delete the old record. */
if( hasFK || chngKey || pPk!=0 ){
sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, 0);
}
if( bReplace || chngKey ){
sqlite3VdbeJumpHere(v, addr1);
}
if( hasFK ){
sqlite3FkCheck(pParse, pTab, 0, regNewRowid, aXRef, chngKey);
}
/* Insert the new index entries and the new record. */
sqlite3CompleteInsertion(pParse, pTab, iDataCur, iIdxCur,
regNewRowid, aRegIdx, 1, 0, 0);
/* 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 updated. */
if( hasFK ){
sqlite3FkActions(pParse, pTab, pChanges, regOldRowid, aXRef, chngKey);
}
}
/* Increment the row counter
*/
if( (db->flags & SQLITE_CountRows) && !pParse->pTriggerTab){
sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
}
sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges,
TRIGGER_AFTER, pTab, regOldRowid, onError, labelContinue);
/* Repeat the above with the next record to be updated, until
** all record selected by the WHERE clause have been updated.
*/
if( okOnePass ){
/* Nothing to do at end-of-loop for a single-pass */
}else if( pPk ){
sqlite3VdbeResolveLabel(v, labelContinue);
sqlite3VdbeAddOp2(v, OP_Next, iEph, addrTop); VdbeCoverage(v);
}else{
sqlite3VdbeGoto(v, labelContinue);
}
sqlite3VdbeResolveLabel(v, labelBreak);
/* Close all tables */
for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
assert( aRegIdx );
if( aToOpen[i+1] ){
sqlite3VdbeAddOp2(v, OP_Close, iIdxCur+i, 0);
}
}
if( iDataCur<iIdxCur ) sqlite3VdbeAddOp2(v, OP_Close, iDataCur, 0);
/* 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 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->pTriggerTab && !pParse->nested ){
sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
sqlite3VdbeSetNumCols(v, 1);
sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows updated", SQLITE_STATIC);
}
update_cleanup:
sqlite3AuthContextPop(&sContext);
sqlite3DbFree(db, aXRef); /* Also frees aRegIdx[] and aToOpen[] */
sqlite3SrcListDelete(db, pTabList);
sqlite3ExprListDelete(db, pChanges);
sqlite3ExprDelete(db, pWhere);
return;
}
/*
** 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 */
){
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 = -1; /* 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;
bComplex = pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0);
#else
# define pTrigger 0
# define isView 0
#endif
#ifdef SQLITE_OMIT_VIEW
# undef isView
# define isView 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, 1, 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, iTabCur);
iDataCur = iIdxCur = iTabCur;
}
#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 ){
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. */
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,
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 );
/* Keep track of the number of rows to be deleted */
if( db->flags & SQLITE_CountRows ){
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 + 1;
iKey = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iTabCur, iKey, 0);
if( iKey>pParse->nMem ) pParse->nMem = 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);
sqlite3VdbeAddOp2(v, OP_IdxInsert, iEphCur, iKey);
}else{
/* Add the rowid of the row to be deleted to the RowSet */
nKey = 1; /* OP_Seek 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(v);
}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);
sqlite3VdbeAddOp2(v, OP_RowKey, 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);
sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iKey, pVTab, P4_VTAB);
sqlite3VdbeChangeP5(v, OE_Abort);
assert( eOnePass==ONEPASS_OFF || eOnePass==ONEPASS_SINGLE );
sqlite3MayAbort(pParse);
if( eOnePass==ONEPASS_SINGLE && sqlite3IsToplevel(pParse) ){
pParse->isMultiWrite = 0;
}
}else
#endif
{
int count = (pParse->nested==0); /* True to count changes */
int iIdxNoSeek = -1;
if( bComplex==0 && aiCurOnePass[1]!=iDataCur ){
iIdxNoSeek = aiCurOnePass[1];
}
sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
iKey, nKey, count, OE_Default, eOnePass, iIdxNoSeek);
}
/* 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);
}
/* Close the cursors open on the table and its indexes. */
if( !isView && !IsVirtual(pTab) ){
if( !pPk ) sqlite3VdbeAddOp1(v, OP_Close, iDataCur);
for(i=0, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
sqlite3VdbeAddOp1(v, OP_Close, iIdxCur + i);
}
}
} /* 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( (db->flags&SQLITE_CountRows) && !pParse->nested && !pParse->pTriggerTab ){
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);
sqlite3DbFree(db, aToOpen);
return;
}
/*
** 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 */
ExprList *pOrderBy, /* ORDER BY clause. May be null */
Expr *pLimit, /* LIMIT clause. May be null */
Upsert *pUpsert /* ON CONFLICT clause, or null */
){
int i, j; /* Loop counters */
Table *pTab; /* The table to be updated */
int addrTop = 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 */
Index *pPk; /* The PRIMARY KEY index for WITHOUT ROWID tables */
int nIdx; /* Number of indices that need updating */
int iBaseCur; /* Base cursor number */
int iDataCur; /* Cursor for the canonical data btree */
int iIdxCur; /* Cursor for the first index */
sqlite3 *db; /* The database structure */
int *aRegIdx = 0; /* First register in array assigned to each index */
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. */
u8 *aToOpen; /* 1 for tables and indices to be opened */
u8 chngPk; /* PRIMARY KEY changed in a WITHOUT ROWID table */
u8 chngRowid; /* Rowid changed in a normal table */
u8 chngKey; /* Either chngPk or chngRowid */
Expr *pRowidExpr = 0; /* Expression defining the new record number */
AuthContext sContext; /* The authorization context */
NameContext sNC; /* The name-context to resolve expressions in */
int iDb; /* Database containing the table being updated */
int eOnePass; /* ONEPASS_XXX value from where.c */
int hasFK; /* True if foreign key processing is required */
int labelBreak; /* Jump here to break out of UPDATE loop */
int labelContinue; /* Jump here to continue next step of UPDATE loop */
int flags; /* Flags for sqlite3WhereBegin() */
#ifndef SQLITE_OMIT_TRIGGER
int isView; /* True when updating a view (INSTEAD OF trigger) */
Trigger *pTrigger; /* List of triggers on pTab, if required */
int tmask; /* Mask of TRIGGER_BEFORE|TRIGGER_AFTER */
#endif
int newmask; /* Mask of NEW.* columns accessed by BEFORE triggers */
int iEph = 0; /* Ephemeral table holding all primary key values */
int nKey = 0; /* Number of elements in regKey for WITHOUT ROWID */
int aiCurOnePass[2]; /* The write cursors opened by WHERE_ONEPASS */
int addrOpen = 0; /* Address of OP_OpenEphemeral */
int iPk = 0; /* First of nPk cells holding PRIMARY KEY value */
i16 nPk = 0; /* Number of components of the PRIMARY KEY */
int bReplace = 0; /* True if REPLACE conflict resolution might happen */
/* Register Allocations */
int regRowCount = 0; /* A count of rows changed */
int regOldRowid = 0; /* The old rowid */
int regNewRowid = 0; /* The new rowid */
int regNew = 0; /* Content of the NEW.* table in triggers */
int regOld = 0; /* Content of OLD.* table in triggers */
int regRowSet = 0; /* Rowset of rows to be updated */
int regKey = 0; /* composite PRIMARY KEY value */
memset(&sContext, 0, sizeof(sContext));
db = pParse->db;
if( pParse->nErr || db->mallocFailed ){
goto update_cleanup;
}
assert( pTabList->nSrc==1 );
/* Locate the table which we want to update.
*/
pTab = sqlite3SrcListLookup(pParse, pTabList);
if( pTab==0 ) goto update_cleanup;
iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
/* Figure out if we have any triggers and if the table being
** updated is a view.
*/
#ifndef SQLITE_OMIT_TRIGGER
pTrigger = sqlite3TriggersExist(pParse, pTab, TK_UPDATE, pChanges, &tmask);
isView = pTab->pSelect!=0;
assert( pTrigger || tmask==0 );
#else
# define pTrigger 0
# define isView 0
# define tmask 0
#endif
#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, "UPDATE"
);
pOrderBy = 0;
pLimit = 0;
}
#endif
if( sqlite3ViewGetColumnNames(pParse, pTab) ){
goto update_cleanup;
}
if( sqlite3IsReadOnly(pParse, pTab, tmask) ){
goto update_cleanup;
}
/* 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.
*/
iBaseCur = iDataCur = pParse->nTab++;
iIdxCur = iDataCur+1;
pPk = HasRowid(pTab) ? 0 : sqlite3PrimaryKeyIndex(pTab);
testcase( pPk!=0 && pPk!=pTab->pIndex );
for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){
if( pPk==pIdx ){
iDataCur = pParse->nTab;
}
pParse->nTab++;
}
if( pUpsert ){
/* On an UPSERT, reuse the same cursors already opened by INSERT */
iDataCur = pUpsert->iDataCur;
iIdxCur = pUpsert->iIdxCur;
pParse->nTab = iBaseCur;
}
pTabList->a[0].iCursor = iDataCur;
/* Allocate space for aXRef[], aRegIdx[], and aToOpen[].
** Initialize aXRef[] and aToOpen[] to their default values.
*/
aXRef = sqlite3DbMallocRawNN(db, sizeof(int) * (pTab->nCol+nIdx) + nIdx+2 );
if( aXRef==0 ) goto update_cleanup;
aRegIdx = aXRef+pTab->nCol;
aToOpen = (u8*)(aRegIdx+nIdx);
memset(aToOpen, 1, nIdx+1);
aToOpen[nIdx+1] = 0;
for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;
/* Initialize the name-context */
memset(&sNC, 0, sizeof(sNC));
sNC.pParse = pParse;
sNC.pSrcList = pTabList;
sNC.uNC.pUpsert = pUpsert;
sNC.ncFlags = NC_UUpsert;
/* 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 = chngPk = 0;
for(i=0; i<pChanges->nExpr; i++){
if( sqlite3ResolveExprNames(&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;
}else if( pPk && (pTab->aCol[j].colFlags & COLFLAG_PRIMKEY)!=0 ){
chngPk = 1;
}
aXRef[j] = i;
break;
}
}
if( j>=pTab->nCol ){
if( pPk==0 && sqlite3IsRowid(pChanges->a[i].zName) ){
j = -1;
chngRowid = 1;
pRowidExpr = pChanges->a[i].pExpr;
}else{
sqlite3ErrorMsg(pParse, "no such column: %s", pChanges->a[i].zName);
pParse->checkSchema = 1;
goto update_cleanup;
}
}
#ifndef SQLITE_OMIT_AUTHORIZATION
{
int rc;
rc = sqlite3AuthCheck(pParse, SQLITE_UPDATE, pTab->zName,
j<0 ? "ROWID" : pTab->aCol[j].zName,
db->aDb[iDb].zDbSName);
if( rc==SQLITE_DENY ){
goto update_cleanup;
}else if( rc==SQLITE_IGNORE ){
aXRef[j] = -1;
}
}
#endif
}
assert( (chngRowid & chngPk)==0 );
assert( chngRowid==0 || chngRowid==1 );
assert( chngPk==0 || chngPk==1 );
chngKey = chngRowid + chngPk;
/* The SET expressions are not actually used inside the WHERE loop.
** So reset the colUsed mask. Unless this is a virtual table. In that
** case, set all bits of the colUsed mask (to ensure that the virtual
** table implementation makes all columns available).
*/
pTabList->a[0].colUsed = IsVirtual(pTab) ? ALLBITS : 0;
hasFK = sqlite3FkRequired(pParse, pTab, aXRef, chngKey);
/* There is one entry in the aRegIdx[] array for each index on the table
** being updated. Fill in aRegIdx[] with a register number that will hold
** the key for accessing each index.
*/
if( onError==OE_Replace ) bReplace = 1;
for(j=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, j++){
int reg;
if( chngKey || hasFK>1 || pIdx==pPk
|| indexWhereClauseMightChange(pIdx,aXRef,chngRowid)
){
reg = ++pParse->nMem;
pParse->nMem += pIdx->nColumn;
}else{
reg = 0;
for(i=0; i<pIdx->nKeyCol; i++){
if( indexColumnIsBeingUpdated(pIdx, i, aXRef, chngRowid) ){
reg = ++pParse->nMem;
pParse->nMem += pIdx->nColumn;
if( onError==OE_Default && pIdx->onError==OE_Replace ){
bReplace = 1;
}
break;
}
}
}
if( reg==0 ) aToOpen[j+1] = 0;
aRegIdx[j] = reg;
}
if( bReplace ){
/* If REPLACE conflict resolution might be invoked, open cursors on all
** indexes in case they are needed to delete records. */
memset(aToOpen, 1, nIdx+1);
}
/* Begin generating code. */
v = sqlite3GetVdbe(pParse);
if( v==0 ) goto update_cleanup;
if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
sqlite3BeginWriteOperation(pParse, pTrigger || hasFK, iDb);
/* Allocate required registers. */
if( !IsVirtual(pTab) ){
regRowSet = ++pParse->nMem;
regOldRowid = regNewRowid = ++pParse->nMem;
if( chngPk || pTrigger || hasFK ){
regOld = pParse->nMem + 1;
pParse->nMem += pTab->nCol;
}
if( chngKey || pTrigger || hasFK ){
regNewRowid = ++pParse->nMem;
}
regNew = pParse->nMem + 1;
pParse->nMem += pTab->nCol;
}
/* Start the view context. */
if( isView ){
sqlite3AuthContextPush(pParse, &sContext, pTab->zName);
}
/* If we are trying to update 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, iDataCur
);
pOrderBy = 0;
pLimit = 0;
}
#endif
/* Resolve the column names in all the expressions in the
** WHERE clause.
*/
if( sqlite3ResolveExprNames(&sNC, pWhere) ){
goto update_cleanup;
}
#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Virtual tables must be handled separately */
if( IsVirtual(pTab) ){
updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
pWhere, onError);
goto update_cleanup;
}
#endif
/* Jump to labelBreak to abandon further processing of this UPDATE */
labelContinue = labelBreak = sqlite3VdbeMakeLabel(pParse);
/* Not an UPSERT. Normal processing. Begin by
** initialize the count of updated rows */
if( (db->flags&SQLITE_CountRows)!=0
&& !pParse->pTriggerTab
&& !pParse->nested
&& pUpsert==0
){
regRowCount = ++pParse->nMem;
sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
}
if( HasRowid(pTab) ){
sqlite3VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldRowid);
}else{
assert( pPk!=0 );
nPk = pPk->nKeyCol;
iPk = pParse->nMem+1;
pParse->nMem += nPk;
regKey = ++pParse->nMem;
if( pUpsert==0 ){
iEph = pParse->nTab++;
sqlite3VdbeAddOp3(v, OP_Null, 0, iPk, iPk+nPk-1);
addrOpen = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, iEph, nPk);
sqlite3VdbeSetP4KeyInfo(pParse, pPk);
}
}
if( pUpsert ){
/* If this is an UPSERT, then all cursors have already been opened by
** the outer INSERT and the data cursor should be pointing at the row
** that is to be updated. So bypass the code that searches for the
** row(s) to be updated.
*/
pWInfo = 0;
eOnePass = ONEPASS_SINGLE;
sqlite3ExprIfFalse(pParse, pWhere, labelBreak, SQLITE_JUMPIFNULL);
}else{
/* Begin the database scan.
**
** Do not consider a single-pass strategy for a multi-row update if
** there are any triggers or foreign keys to process, or rows may
** be deleted as a result of REPLACE conflict handling. Any of these
** things might disturb a cursor being used to scan through the table
** or index, causing a single-pass approach to malfunction. */
flags = WHERE_ONEPASS_DESIRED|WHERE_SEEK_UNIQ_TABLE;
if( !pParse->nested && !pTrigger && !hasFK && !chngKey && !bReplace ){
flags |= WHERE_ONEPASS_MULTIROW;
}
pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0, flags, iIdxCur);
if( pWInfo==0 ) goto update_cleanup;
/* A one-pass strategy that might update more than one row may not
** be used if any column of the index used for the scan is being
** updated. Otherwise, if there is an index on "b", statements like
** the following could create an infinite loop:
**
** UPDATE t1 SET b=b+1 WHERE b>?
**
** Fall back to ONEPASS_OFF if where.c has selected a ONEPASS_MULTI
** strategy that uses an index for which one or more columns are being
** updated. */
eOnePass = sqlite3WhereOkOnePass(pWInfo, aiCurOnePass);
if( eOnePass!=ONEPASS_SINGLE ){
sqlite3MultiWrite(pParse);
if( eOnePass==ONEPASS_MULTI ){
int iCur = aiCurOnePass[1];
if( iCur>=0 && iCur!=iDataCur && aToOpen[iCur-iBaseCur] ){
eOnePass = ONEPASS_OFF;
}
assert( iCur!=iDataCur || !HasRowid(pTab) );
}
}
}
if( HasRowid(pTab) ){
/* Read the rowid of the current row of the WHERE scan. In ONEPASS_OFF
** mode, write the rowid into the FIFO. In either of the one-pass modes,
** leave it in register regOldRowid. */
sqlite3VdbeAddOp2(v, OP_Rowid, iDataCur, regOldRowid);
if( eOnePass==ONEPASS_OFF ){
sqlite3VdbeAddOp2(v, OP_RowSetAdd, regRowSet, regOldRowid);
}
}else{
/* Read the PK of the current row into an array of registers. In
** ONEPASS_OFF mode, serialize the array into a record and store it in
** the ephemeral table. Or, in ONEPASS_SINGLE or MULTI mode, change
** the OP_OpenEphemeral instruction to a Noop (the ephemeral table
** is not required) and leave the PK fields in the array of registers. */
for(i=0; i<nPk; i++){
assert( pPk->aiColumn[i]>=0 );
sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur,pPk->aiColumn[i],iPk+i);
}
if( eOnePass ){
if( addrOpen ) sqlite3VdbeChangeToNoop(v, addrOpen);
nKey = nPk;
regKey = iPk;
}else{
sqlite3VdbeAddOp4(v, OP_MakeRecord, iPk, nPk, regKey,
sqlite3IndexAffinityStr(db, pPk), nPk);
sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iEph, regKey, iPk, nPk);
}
}
if( pUpsert==0 ){
if( eOnePass!=ONEPASS_MULTI ){
sqlite3WhereEnd(pWInfo);
}
if( !isView ){
int addrOnce = 0;
/* Open every index that needs updating. */
if( eOnePass!=ONEPASS_OFF ){
if( aiCurOnePass[0]>=0 ) aToOpen[aiCurOnePass[0]-iBaseCur] = 0;
if( aiCurOnePass[1]>=0 ) aToOpen[aiCurOnePass[1]-iBaseCur] = 0;
}
if( eOnePass==ONEPASS_MULTI && (nIdx-(aiCurOnePass[1]>=0))>0 ){
addrOnce = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
}
sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, 0, iBaseCur,
aToOpen, 0, 0);
if( addrOnce ) sqlite3VdbeJumpHere(v, addrOnce);
}
/* Top of the update loop */
if( eOnePass!=ONEPASS_OFF ){
if( !isView && aiCurOnePass[0]!=iDataCur && aiCurOnePass[1]!=iDataCur ){
assert( pPk );
sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelBreak, regKey,nKey);
VdbeCoverage(v);
}
if( eOnePass!=ONEPASS_SINGLE ){
labelContinue = sqlite3VdbeMakeLabel(pParse);
}
sqlite3VdbeAddOp2(v, OP_IsNull, pPk ? regKey : regOldRowid, labelBreak);
VdbeCoverageIf(v, pPk==0);
VdbeCoverageIf(v, pPk!=0);
}else if( pPk ){
labelContinue = sqlite3VdbeMakeLabel(pParse);
sqlite3VdbeAddOp2(v, OP_Rewind, iEph, labelBreak); VdbeCoverage(v);
addrTop = sqlite3VdbeAddOp2(v, OP_RowData, iEph, regKey);
sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelContinue, regKey, 0);
VdbeCoverage(v);
}else{
labelContinue = sqlite3VdbeAddOp3(v, OP_RowSetRead, regRowSet,labelBreak,
regOldRowid);
VdbeCoverage(v);
sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, labelContinue, regOldRowid);
VdbeCoverage(v);
}
}
/* If the rowid value will change, set register regNewRowid to
** contain the new value. If the rowid is not being modified,
** then regNewRowid is the same register as regOldRowid, which is
** already populated. */
assert( chngKey || pTrigger || hasFK || regOldRowid==regNewRowid );
if( chngRowid ){
sqlite3ExprCode(pParse, pRowidExpr, regNewRowid);
sqlite3VdbeAddOp1(v, OP_MustBeInt, regNewRowid); VdbeCoverage(v);
}
/* Compute the old pre-UPDATE content of the row being changed, if that
** information is needed */
if( chngPk || hasFK || pTrigger ){
u32 oldmask = (hasFK ? sqlite3FkOldmask(pParse, pTab) : 0);
oldmask |= sqlite3TriggerColmask(pParse,
pTrigger, pChanges, 0, TRIGGER_BEFORE|TRIGGER_AFTER, pTab, onError
);
for(i=0; i<pTab->nCol; i++){
if( oldmask==0xffffffff
|| (i<32 && (oldmask & MASKBIT32(i))!=0)
|| (pTab->aCol[i].colFlags & COLFLAG_PRIMKEY)!=0
){
testcase( oldmask!=0xffffffff && i==31 );
sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, regOld+i);
}else{
sqlite3VdbeAddOp2(v, OP_Null, 0, regOld+i);
}
}
if( chngRowid==0 && pPk==0 ){
sqlite3VdbeAddOp2(v, OP_Copy, regOldRowid, regNewRowid);
}
}
/* Populate the array of registers beginning at regNew with the new
** row data. This array is used to check constants, create the new
** table and index records, and as the values for any new.* references
** made by triggers.
**
** If there are one or more BEFORE triggers, then do not populate the
** registers associated with columns that are (a) not modified by
** this UPDATE statement and (b) not accessed by new.* references. The
** values for registers not modified by the UPDATE must be reloaded from
** the database after the BEFORE triggers are fired anyway (as the trigger
** may have modified them). So not loading those that are not going to
** be used eliminates some redundant opcodes.
*/
newmask = sqlite3TriggerColmask(
pParse, pTrigger, pChanges, 1, TRIGGER_BEFORE, pTab, onError
);
for(i=0; i<pTab->nCol; i++){
if( i==pTab->iPKey ){
sqlite3VdbeAddOp2(v, OP_Null, 0, regNew+i);
}else{
j = aXRef[i];
if( j>=0 ){
sqlite3ExprCode(pParse, pChanges->a[j].pExpr, regNew+i);
}else if( 0==(tmask&TRIGGER_BEFORE) || i>31 || (newmask & MASKBIT32(i)) ){
/* This branch loads the value of a column that will not be changed
** into a register. This is done if there are no BEFORE triggers, or
** if there are one or more BEFORE triggers that use this value via
** a new.* reference in a trigger program.
*/
testcase( i==31 );
testcase( i==32 );
sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, regNew+i);
}else{
sqlite3VdbeAddOp2(v, OP_Null, 0, regNew+i);
}
}
}
/* Fire any BEFORE UPDATE triggers. This happens before constraints are
** verified. One could argue that this is wrong.
*/
if( tmask&TRIGGER_BEFORE ){
sqlite3TableAffinity(v, pTab, regNew);
sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges,
TRIGGER_BEFORE, pTab, regOldRowid, onError, labelContinue);
/* The row-trigger may have deleted the row being updated. In this
** case, jump to the next row. No updates or AFTER triggers are
** required. This behavior - what happens when the row being updated
** is deleted or renamed by a BEFORE trigger - is left undefined in the
** documentation.
*/
if( pPk ){
sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, labelContinue,regKey,nKey);
VdbeCoverage(v);
}else{
sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, labelContinue, regOldRowid);
VdbeCoverage(v);
}
/* After-BEFORE-trigger-reload-loop:
** If it did not delete it, the BEFORE trigger may still have modified
** some of the columns of the row being updated. Load the values for
** all columns not modified by the update statement into their registers
** in case this has happened. Only unmodified columns are reloaded.
** The values computed for modified columns use the values before the
** BEFORE trigger runs. See test case trigger1-18.0 (added 2018-04-26)
** for an example.
*/
for(i=0; i<pTab->nCol; i++){
if( aXRef[i]<0 && i!=pTab->iPKey ){
sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, regNew+i);
}
}
}
if( !isView ){
int addr1 = 0; /* Address of jump instruction */
/* Do constraint checks. */
assert( regOldRowid>0 );
sqlite3GenerateConstraintChecks(pParse, pTab, aRegIdx, iDataCur, iIdxCur,
regNewRowid, regOldRowid, chngKey, onError, labelContinue, &bReplace,
aXRef, 0);
/* Do FK constraint checks. */
if( hasFK ){
sqlite3FkCheck(pParse, pTab, regOldRowid, 0, aXRef, chngKey);
}
/* Delete the index entries associated with the current record. */
if( bReplace || chngKey ){
if( pPk ){
addr1 = sqlite3VdbeAddOp4Int(v, OP_NotFound, iDataCur, 0, regKey, nKey);
}else{
addr1 = sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, 0, regOldRowid);
}
VdbeCoverageNeverTaken(v);
}
sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur, aRegIdx, -1);
/* If changing the rowid value, or if there are foreign key constraints
** to process, delete the old record. Otherwise, add a noop OP_Delete
** to invoke the pre-update hook.
**
** That (regNew==regnewRowid+1) is true is also important for the
** pre-update hook. If the caller invokes preupdate_new(), the returned
** value is copied from memory cell (regNewRowid+1+iCol), where iCol
** is the column index supplied by the user.
*/
assert( regNew==regNewRowid+1 );
#ifdef SQLITE_ENABLE_PREUPDATE_HOOK
sqlite3VdbeAddOp3(v, OP_Delete, iDataCur,
OPFLAG_ISUPDATE | ((hasFK>1 || chngKey) ? 0 : OPFLAG_ISNOOP),
regNewRowid
);
if( eOnePass==ONEPASS_MULTI ){
assert( hasFK==0 && chngKey==0 );
sqlite3VdbeChangeP5(v, OPFLAG_SAVEPOSITION);
}
if( !pParse->nested ){
sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
}
#else
if( hasFK>1 || chngKey ){
sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, 0);
}
#endif
if( bReplace || chngKey ){
sqlite3VdbeJumpHere(v, addr1);
}
if( hasFK ){
sqlite3FkCheck(pParse, pTab, 0, regNewRowid, aXRef, chngKey);
}
/* Insert the new index entries and the new record. */
sqlite3CompleteInsertion(
pParse, pTab, iDataCur, iIdxCur, regNewRowid, aRegIdx,
OPFLAG_ISUPDATE | (eOnePass==ONEPASS_MULTI ? OPFLAG_SAVEPOSITION : 0),
0, 0
);
/* 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 updated. */
if( hasFK ){
sqlite3FkActions(pParse, pTab, pChanges, regOldRowid, aXRef, chngKey);
}
}
/* Increment the row counter
*/
if( regRowCount ){
sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
}
sqlite3CodeRowTrigger(pParse, pTrigger, TK_UPDATE, pChanges,
TRIGGER_AFTER, pTab, regOldRowid, onError, labelContinue);
/* Repeat the above with the next record to be updated, until
** all record selected by the WHERE clause have been updated.
*/
if( eOnePass==ONEPASS_SINGLE ){
/* Nothing to do at end-of-loop for a single-pass */
}else if( eOnePass==ONEPASS_MULTI ){
sqlite3VdbeResolveLabel(v, labelContinue);
sqlite3WhereEnd(pWInfo);
}else if( pPk ){
sqlite3VdbeResolveLabel(v, labelContinue);
sqlite3VdbeAddOp2(v, OP_Next, iEph, addrTop); VdbeCoverage(v);
}else{
sqlite3VdbeGoto(v, labelContinue);
}
sqlite3VdbeResolveLabel(v, labelBreak);
/* 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 && pUpsert==0 ){
sqlite3AutoincrementEnd(pParse);
}
/*
** Return the number of rows that were changed, if we are tracking
** that information.
*/
if( regRowCount ){
sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
sqlite3VdbeSetNumCols(v, 1);
sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows updated", SQLITE_STATIC);
}
update_cleanup:
sqlite3AuthContextPop(&sContext);
sqlite3DbFree(db, aXRef); /* Also frees aRegIdx[] and aToOpen[] */
sqlite3SrcListDelete(db, pTabList);
sqlite3ExprListDelete(db, pChanges);
sqlite3ExprDelete(db, pWhere);
#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT)
sqlite3ExprListDelete(db, pOrderBy);
sqlite3ExprDelete(db, pLimit);
#endif
return;
}
