/*
** 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 */
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(db, 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, 0,
SF_IncludeHidden, 0, 0);
sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur);
sqlite3Select(pParse, pSel, &dest);
sqlite3SelectDelete(db, pSel);
}
/*
** 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 */
int iCur /* Cursor number for ephemerial table */
){
SelectDest dest;
Select *pDup;
sqlite3 *db = pParse->db;
pDup = sqlite3SelectDup(db, pView->pSelect, 0);
if( pWhere ){
SrcList *pFrom;
pWhere = sqlite3ExprDup(db, pWhere, 0);
pFrom = sqlite3SrcListAppend(db, 0, 0, 0);
if( pFrom ){
assert( pFrom->nSrc==1 );
pFrom->a[0].zAlias = sqlite3DbStrDup(db, pView->zName);
pFrom->a[0].pSelect = pDup;
assert( pFrom->a[0].pOn==0 );
assert( pFrom->a[0].pUsing==0 );
}else{
sqlite3SelectDelete(db, pDup);
}
pDup = sqlite3SelectNew(pParse, 0, pFrom, pWhere, 0, 0, 0, 0, 0, 0);
if( pDup ) pDup->selFlags |= SF_Materialize;
}
sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur);
sqlite3Select(pParse, pDup, &dest);
sqlite3SelectDelete(db, pDup);
}
/*
** 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 */
int iCur /* Cursor number for ephemerial table */
){
SelectDest dest;
Select *pDup;
sqlite3 *db = pParse->db;
pDup = sqlite3SelectDup(db, pView->pSelect);
if( pWhere ){
SrcList *pFrom;
Token viewName;
pWhere = sqlite3ExprDup(db, pWhere);
viewName.z = (u8*)pView->zName;
viewName.n = (unsigned int)sqlite3Strlen30((const char*)viewName.z);
pFrom = sqlite3SrcListAppendFromTerm(pParse, 0, 0, 0, &viewName, pDup, 0,0);
pDup = sqlite3SelectNew(pParse, 0, pFrom, pWhere, 0, 0, 0, 0, 0, 0);
}
sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur);
sqlite3Select(pParse, pDup, &dest);
sqlite3SelectDelete(db, pDup);
}
/*
** 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 */
Select *pView, /* View definition */
Expr *pWhere, /* Optional WHERE clause to be added */
int iCur /* Cursor number for ephemerial table */
){
SelectDest dest;
Select *pDup;
sqlite3 *db = pParse->db;
pDup = sqlite3SelectDup(db, pView);
if( pWhere ){
SrcList *pFrom;
pWhere = sqlite3ExprDup(db, pWhere);
pFrom = sqlite3SrcListAppendFromTerm(pParse, 0, 0, 0, 0, pDup, 0, 0);
pDup = sqlite3SelectNew(pParse, 0, pFrom, pWhere, 0, 0, 0, 0, 0, 0);
}
sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur);
sqlite3Select(pParse, pDup, &dest, 0, 0, 0);
sqlite3SelectDelete(db, pDup);
}
/*
** 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 */
Expr *pOffset, /* The OFFSET clause. May be null */
char *zStmtType /* Either DELETE or UPDATE. For err msgs. */
){
Expr *pWhereRowid = NULL; /* WHERE rowid .. */
Expr *pInClause = NULL; /* WHERE rowid IN ( select ) */
Expr *pSelectRowid = NULL; /* SELECT rowid ... */
ExprList *pEList = NULL; /* Expression list contaning only pSelectRowid */
SrcList *pSelectSrc = NULL; /* SELECT rowid FROM x ... (dup of pSrc) */
Select *pSelect = NULL; /* Complete SELECT tree */
/* 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);
goto limit_where_cleanup;
}
/* We only need to generate a select expression if there
** is a limit/offset term to enforce.
*/
if( pLimit == 0 ) {
/* if pLimit is null, pOffset will always be null as well. */
assert( pOffset == 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
** );
*/
pSelectRowid = sqlite3PExpr(pParse, TK_ROW, 0, 0, 0);
if( pSelectRowid == 0 ) goto limit_where_cleanup;
pEList = sqlite3ExprListAppend(pParse, 0, pSelectRowid);
if( pEList == 0 ) goto limit_where_cleanup;
/* duplicate the FROM clause as it is needed by both the DELETE/UPDATE tree
** and the SELECT subtree. */
pSelectSrc = sqlite3SrcListDup(pParse->db, pSrc, 0);
if( pSelectSrc == 0 ) {
sqlite3ExprListDelete(pParse->db, pEList);
goto limit_where_cleanup;
}
/* generate the SELECT expression tree. */
pSelect = sqlite3SelectNew(pParse,pEList,pSelectSrc,pWhere,0,0,
pOrderBy,0,pLimit,pOffset);
if( pSelect == 0 ) return 0;
/* now generate the new WHERE rowid IN clause for the DELETE/UDPATE */
pWhereRowid = sqlite3PExpr(pParse, TK_ROW, 0, 0, 0);
pInClause = pWhereRowid ? sqlite3PExpr(pParse, TK_IN, pWhereRowid, 0, 0) : 0;
sqlite3PExprAddSelect(pParse, pInClause, pSelect);
return pInClause;
limit_where_cleanup:
sqlite3ExprDelete(pParse->db, pWhere);
sqlite3ExprListDelete(pParse->db, pOrderBy);
sqlite3ExprDelete(pParse->db, pLimit);
sqlite3ExprDelete(pParse->db, pOffset);
return 0;
}
/*
** 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;
}
static void updateVirtualTable(
Parse *pParse,
SrcList *pSrc,
Table *pTab,
ExprList *pChanges,
Expr *pRowid,
int *aXRef,
Expr *pWhere
){
Vdbe *v = pParse->pVdbe;
ExprList *pEList = 0;
Select *pSelect = 0;
Expr *pExpr;
int ephemTab;
int i;
int addr;
int iReg;
sqlite3 *db = pParse->db;
const char *pVTab = (const char*)sqlite3GetVTable(db, pTab);
SelectDest dest;
pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ID, "_rowid_"));
if( pRowid ){
pEList = sqlite3ExprListAppend(pParse, pEList,
sqlite3ExprDup(db, pRowid, 0));
}
assert( pTab->iPKey<0 );
for(i=0; i<pTab->nCol; i++){
if( aXRef[i]>=0 ){
pExpr = sqlite3ExprDup(db, pChanges->a[aXRef[i]].pExpr, 0);
}else{
pExpr = sqlite3Expr(db, TK_ID, pTab->aCol[i].zName);
}
pEList = sqlite3ExprListAppend(pParse, pEList, pExpr);
}
pSelect = sqlite3SelectNew(pParse, pEList, pSrc, pWhere, 0, 0, 0, 0, 0, 0);
assert( v );
ephemTab = pParse->nTab++;
sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, pTab->nCol+1+(pRowid!=0));
sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
sqlite3SelectDestInit(&dest, SRT_Table, ephemTab);
sqlite3Select(pParse, pSelect, &dest);
iReg = ++pParse->nMem;
pParse->nMem += pTab->nCol+1;
addr = sqlite3VdbeAddOp2(v, OP_Rewind, ephemTab, 0);
sqlite3VdbeAddOp3(v, OP_Column, ephemTab, 0, iReg);
sqlite3VdbeAddOp3(v, OP_Column, ephemTab, (pRowid?1:0), iReg+1);
for(i=0; i<pTab->nCol; i++){
sqlite3VdbeAddOp3(v, OP_Column, ephemTab, i+1+(pRowid!=0), iReg+2+i);
}
sqlite3VtabMakeWritable(pParse, pTab);
sqlite3VdbeAddOp4(v, OP_VUpdate, 0, pTab->nCol+2, iReg, pVTab, P4_VTAB);
sqlite3MayAbort(pParse);
sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr+1);
sqlite3VdbeJumpHere(v, addr);
sqlite3VdbeAddOp2(v, OP_Close, ephemTab, 0);
sqlite3SelectDelete(db, pSelect);
}
/*
** Generate code for an UPDATE of a virtual table.
**
** The strategy is that we create an ephemerial table that contains
** for each row to be changed:
**
** (A) The original rowid of that row.
** (B) The revised rowid for the row. (note1)
** (C) The content of every column in the row.
**
** Then we loop over this ephemeral table and for each row in
** the ephermeral table call VUpdate.
**
** When finished, drop the ephemeral table.
**
** (note1) Actually, if we know in advance that (A) is always the same
** as (B) we only store (A), then duplicate (A) when pulling
** it out of the ephemeral table before calling VUpdate.
*/
static void updateVirtualTable(
Parse *pParse, /* The parsing context */
SrcList *pSrc, /* The virtual table to be modified */
Table *pTab, /* The virtual table */
ExprList *pChanges, /* The columns to change in the UPDATE statement */
Expr *pRowid, /* Expression used to recompute the rowid */
int *aXRef, /* Mapping from columns of pTab to entries in pChanges */
Expr *pWhere /* WHERE clause of the UPDATE statement */
){
Vdbe *v = pParse->pVdbe; /* Virtual machine under construction */
ExprList *pEList = 0; /* The result set of the SELECT statement */
Select *pSelect = 0; /* The SELECT statement */
Expr *pExpr; /* Temporary expression */
int ephemTab; /* Table holding the result of the SELECT */
int i; /* Loop counter */
int addr; /* Address of top of loop */
int iReg; /* First register in set passed to OP_VUpdate */
sqlite3 *db = pParse->db; /* Database connection */
const char *pVTab = (const char*)sqlite3GetVTable(db, pTab);
SelectDest dest;
/* Construct the SELECT statement that will find the new values for
** all updated rows.
*/
pEList = sqlite3ExprListAppend(pParse, 0, sqlite3Expr(db, TK_ID, "_rowid_"));
if( pRowid ){
pEList = sqlite3ExprListAppend(pParse, pEList,
sqlite3ExprDup(db, pRowid, 0));
}
assert( pTab->iPKey<0 );
for(i=0; i<pTab->nCol; i++){
if( aXRef[i]>=0 ){
pExpr = sqlite3ExprDup(db, pChanges->a[aXRef[i]].pExpr, 0);
}else{
pExpr = sqlite3Expr(db, TK_ID, pTab->aCol[i].zName);
}
pEList = sqlite3ExprListAppend(pParse, pEList, pExpr);
}
pSelect = sqlite3SelectNew(pParse, pEList, pSrc, pWhere, 0, 0, 0, 0, 0, 0);
/* Create the ephemeral table into which the update results will
** be stored.
*/
assert( v );
ephemTab = pParse->nTab++;
sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, pTab->nCol+1+(pRowid!=0));
sqlite3VdbeChangeP5(v, BTREE_UNORDERED);
/* fill the ephemeral table
*/
sqlite3SelectDestInit(&dest, SRT_Table, ephemTab);
sqlite3Select(pParse, pSelect, &dest);
/* Generate code to scan the ephemeral table and call VUpdate. */
iReg = ++pParse->nMem;
pParse->nMem += pTab->nCol+1;
addr = sqlite3VdbeAddOp2(v, OP_Rewind, ephemTab, 0);
sqlite3VdbeAddOp3(v, OP_Column, ephemTab, 0, iReg);
sqlite3VdbeAddOp3(v, OP_Column, ephemTab, (pRowid?1:0), iReg+1);
for(i=0; i<pTab->nCol; i++){
sqlite3VdbeAddOp3(v, OP_Column, ephemTab, i+1+(pRowid!=0), iReg+2+i);
}
sqlite3VtabMakeWritable(pParse, pTab);
sqlite3VdbeAddOp4(v, OP_VUpdate, 0, pTab->nCol+2, iReg, pVTab, P4_VTAB);
sqlite3MayAbort(pParse);
sqlite3VdbeAddOp2(v, OP_Next, ephemTab, addr+1);
sqlite3VdbeJumpHere(v, addr);
sqlite3VdbeAddOp2(v, OP_Close, ephemTab, 0);
/* Cleanup */
sqlite3SelectDelete(db, pSelect);
}
/*
** This function is called when an UPDATE or DELETE operation is being
** compiled on table pTab, which is the parent table of foreign-key pFKey.
** If the current operation is an UPDATE, then the pChanges parameter is
** passed a pointer to the list of columns being modified. If it is a
** DELETE, pChanges is passed a NULL pointer.
**
** It returns a pointer to a Trigger structure containing a trigger
** equivalent to the ON UPDATE or ON DELETE action specified by pFKey.
** If the action is "NO ACTION" or "RESTRICT", then a NULL pointer is
** returned (these actions require no special handling by the triggers
** sub-system, code for them is created by fkScanChildren()).
**
** For example, if pFKey is the foreign key and pTab is table "p" in
** the following schema:
**
** CREATE TABLE p(pk PRIMARY KEY);
** CREATE TABLE c(ck REFERENCES p ON DELETE CASCADE);
**
** then the returned trigger structure is equivalent to:
**
** CREATE TRIGGER ... DELETE ON p BEGIN
** DELETE FROM c WHERE ck = old.pk;
** END;
**
** The returned pointer is cached as part of the foreign key object. It
** is eventually freed along with the rest of the foreign key object by
** sqlite3FkDelete().
*/
static Trigger *fkActionTrigger(
Parse *pParse, /* Parse context */
Table *pTab, /* Table being updated or deleted from */
FKey *pFKey, /* Foreign key to get action for */
ExprList *pChanges /* Change-list for UPDATE, NULL for DELETE */
){
sqlite3 *db = pParse->db; /* Database handle */
int action; /* One of OE_None, OE_Cascade etc. */
Trigger *pTrigger; /* Trigger definition to return */
int iAction = (pChanges!=0); /* 1 for UPDATE, 0 for DELETE */
action = pFKey->aAction[iAction];
pTrigger = pFKey->apTrigger[iAction];
if( action!=OE_None && !pTrigger ){
u8 enableLookaside; /* Copy of db->lookaside.bEnabled */
char const *zFrom; /* Name of child table */
int nFrom; /* Length in bytes of zFrom */
Index *pIdx = 0; /* Parent key index for this FK */
int *aiCol = 0; /* child table cols -> parent key cols */
TriggerStep *pStep = 0; /* First (only) step of trigger program */
Expr *pWhere = 0; /* WHERE clause of trigger step */
ExprList *pList = 0; /* Changes list if ON UPDATE CASCADE */
Select *pSelect = 0; /* If RESTRICT, "SELECT RAISE(...)" */
int i; /* Iterator variable */
Expr *pWhen = 0; /* WHEN clause for the trigger */
if( locateFkeyIndex(pParse, pTab, pFKey, &pIdx, &aiCol) ) return 0;
assert( aiCol || pFKey->nCol==1 );
for(i=0; i<pFKey->nCol; i++){
Token tOld = { "old", 3 }; /* Literal "old" token */
Token tNew = { "new", 3 }; /* Literal "new" token */
Token tFromCol; /* Name of column in child table */
Token tToCol; /* Name of column in parent table */
int iFromCol; /* Idx of column in child table */
Expr *pEq; /* tFromCol = OLD.tToCol */
iFromCol = aiCol ? aiCol[i] : pFKey->aCol[0].iFrom;
assert( iFromCol>=0 );
tToCol.z = pIdx ? pTab->aCol[pIdx->aiColumn[i]].zName : "oid";
tFromCol.z = pFKey->pFrom->aCol[iFromCol].zName;
tToCol.n = sqlite3Strlen30(tToCol.z);
tFromCol.n = sqlite3Strlen30(tFromCol.z);
/* Create the expression "OLD.zToCol = zFromCol". It is important
** that the "OLD.zToCol" term is on the LHS of the = operator, so
** that the affinity and collation sequence associated with the
** parent table are used for the comparison. */
pEq = sqlite3PExpr(pParse, TK_EQ,
sqlite3PExpr(pParse, TK_DOT,
sqlite3PExpr(pParse, TK_ID, 0, 0, &tOld),
sqlite3PExpr(pParse, TK_ID, 0, 0, &tToCol)
, 0),
sqlite3PExpr(pParse, TK_ID, 0, 0, &tFromCol)
, 0);
pWhere = sqlite3ExprAnd(db, pWhere, pEq);
/* For ON UPDATE, construct the next term of the WHEN clause.
** The final WHEN clause will be like this:
**
** WHEN NOT(old.col1 IS new.col1 AND ... AND old.colN IS new.colN)
*/
if( pChanges ){
pEq = sqlite3PExpr(pParse, TK_IS,
sqlite3PExpr(pParse, TK_DOT,
sqlite3PExpr(pParse, TK_ID, 0, 0, &tOld),
sqlite3PExpr(pParse, TK_ID, 0, 0, &tToCol),
0),
sqlite3PExpr(pParse, TK_DOT,
sqlite3PExpr(pParse, TK_ID, 0, 0, &tNew),
sqlite3PExpr(pParse, TK_ID, 0, 0, &tToCol),
0),
0);
pWhen = sqlite3ExprAnd(db, pWhen, pEq);
}
if( action!=OE_Restrict && (action!=OE_Cascade || pChanges) ){
Expr *pNew;
if( action==OE_Cascade ){
pNew = sqlite3PExpr(pParse, TK_DOT,
sqlite3PExpr(pParse, TK_ID, 0, 0, &tNew),
sqlite3PExpr(pParse, TK_ID, 0, 0, &tToCol)
, 0);
}else if( action==OE_SetDflt ){
Expr *pDflt = pFKey->pFrom->aCol[iFromCol].pDflt;
if( pDflt ){
pNew = sqlite3ExprDup(db, pDflt, 0);
}else{
pNew = sqlite3PExpr(pParse, TK_NULL, 0, 0, 0);
}
}else{
pNew = sqlite3PExpr(pParse, TK_NULL, 0, 0, 0);
}
pList = sqlite3ExprListAppend(pParse, pList, pNew);
sqlite3ExprListSetName(pParse, pList, &tFromCol, 0);
}
}
sqlite3DbFree(db, aiCol);
zFrom = pFKey->pFrom->zName;
nFrom = sqlite3Strlen30(zFrom);
if( action==OE_Restrict ){
Token tFrom;
Expr *pRaise;
tFrom.z = zFrom;
tFrom.n = nFrom;
pRaise = sqlite3Expr(db, TK_RAISE, "foreign key constraint failed");
if( pRaise ){
pRaise->affinity = OE_Abort;
}
pSelect = sqlite3SelectNew(pParse,
sqlite3ExprListAppend(pParse, 0, pRaise),
sqlite3SrcListAppend(db, 0, &tFrom, 0),
pWhere,
0, 0, 0, 0, 0, 0
);
pWhere = 0;
}
/* Disable lookaside memory allocation */
enableLookaside = db->lookaside.bEnabled;
db->lookaside.bEnabled = 0;
pTrigger = (Trigger *)sqlite3DbMallocZero(db,
sizeof(Trigger) + /* struct Trigger */
sizeof(TriggerStep) + /* Single step in trigger program */
nFrom + 1 /* Space for pStep->target.z */
);
if( pTrigger ){
pStep = pTrigger->step_list = (TriggerStep *)&pTrigger[1];
pStep->target.z = (char *)&pStep[1];
pStep->target.n = nFrom;
memcpy((char *)pStep->target.z, zFrom, nFrom);
pStep->pWhere = sqlite3ExprDup(db, pWhere, EXPRDUP_REDUCE);
pStep->pExprList = sqlite3ExprListDup(db, pList, EXPRDUP_REDUCE);
pStep->pSelect = sqlite3SelectDup(db, pSelect, EXPRDUP_REDUCE);
if( pWhen ){
pWhen = sqlite3PExpr(pParse, TK_NOT, pWhen, 0, 0);
pTrigger->pWhen = sqlite3ExprDup(db, pWhen, EXPRDUP_REDUCE);
}
}
/* Re-enable the lookaside buffer, if it was disabled earlier. */
db->lookaside.bEnabled = enableLookaside;
sqlite3ExprDelete(db, pWhere);
sqlite3ExprDelete(db, pWhen);
sqlite3ExprListDelete(db, pList);
sqlite3SelectDelete(db, pSelect);
if( db->mallocFailed==1 ){
fkTriggerDelete(db, pTrigger);
return 0;
}
assert( pStep!=0 );
switch( action ){
case OE_Restrict:
pStep->op = TK_SELECT;
break;
case OE_Cascade:
if( !pChanges ){
pStep->op = TK_DELETE;
break;
}
default:
pStep->op = TK_UPDATE;
}
pStep->pTrig = pTrigger;
pTrigger->pSchema = pTab->pSchema;
pTrigger->pTabSchema = pTab->pSchema;
pFKey->apTrigger[iAction] = pTrigger;
pTrigger->op = (pChanges ? TK_UPDATE : TK_DELETE);
}
return pTrigger;
}
/*
** Generate code for an UPDATE of a virtual table.
**
** The strategy is that we create an ephemerial table that contains
** for each row to be changed:
**
** (A) The original rowid of that row.
** (B) The revised rowid for the row. (note1)
** (C) The content of every column in the row.
**
** Then we loop over this ephemeral table and for each row in
** the ephermeral table call VUpdate.
**
** When finished, drop the ephemeral table.
**
** (note1) Actually, if we know in advance that (A) is always the same
** as (B) we only store (A), then duplicate (A) when pulling
** it out of the ephemeral table before calling VUpdate.
*/
static void updateVirtualTable(
Parse *pParse, /* The parsing context */
SrcList *pSrc, /* The virtual table to be modified */
Table *pTab, /* The virtual table */
ExprList *pChanges, /* The columns to change in the UPDATE statement */
Expr *pRowid, /* Expression used to recompute the rowid */
int *aXRef, /* Mapping from columns of pTab to entries in pChanges */
Expr *pWhere /* WHERE clause of the UPDATE statement */
){
Vdbe *v = pParse->pVdbe; /* Virtual machine under construction */
ExprList *pEList = 0; /* The result set of the SELECT statement */
Select *pSelect = 0; /* The SELECT statement */
Expr *pExpr; /* Temporary expression */
int ephemTab; /* Table holding the result of the SELECT */
int i; /* Loop counter */
int addr; /* Address of top of loop */
/* Construct the SELECT statement that will find the new values for
** all updated rows.
*/
pEList = sqlite3ExprListAppend(0, sqlite3CreateIdExpr("_rowid_"), 0);
if( pRowid ){
pEList = sqlite3ExprListAppend(pEList, sqlite3ExprDup(pRowid), 0);
}
assert( pTab->iPKey<0 );
for(i=0; i<pTab->nCol; i++){
if( aXRef[i]>=0 ){
pExpr = sqlite3ExprDup(pChanges->a[aXRef[i]].pExpr);
}else{
pExpr = sqlite3CreateIdExpr(pTab->aCol[i].zName);
}
pEList = sqlite3ExprListAppend(pEList, pExpr, 0);
}
pSelect = sqlite3SelectNew(pEList, pSrc, pWhere, 0, 0, 0, 0, 0, 0);
/* Create the ephemeral table into which the update results will
** be stored.
*/
assert( v );
ephemTab = pParse->nTab++;
sqlite3VdbeAddOp(v, OP_OpenEphemeral, ephemTab, pTab->nCol+1+(pRowid!=0));
/* fill the ephemeral table
*/
sqlite3Select(pParse, pSelect, SRT_Table, ephemTab, 0, 0, 0, 0);
/*
** Generate code to scan the ephemeral table and call VDelete and
** VInsert
*/
sqlite3VdbeAddOp(v, OP_Rewind, ephemTab, 0);
addr = sqlite3VdbeCurrentAddr(v);
sqlite3VdbeAddOp(v, OP_Column, ephemTab, 0);
if( pRowid ){
sqlite3VdbeAddOp(v, OP_Column, ephemTab, 1);
}else{
sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
}
for(i=0; i<pTab->nCol; i++){
sqlite3VdbeAddOp(v, OP_Column, ephemTab, i+1+(pRowid!=0));
}
pParse->pVirtualLock = pTab;
sqlite3VdbeOp3(v, OP_VUpdate, 0, pTab->nCol+2,
(const char*)pTab->pVtab, P3_VTAB);
sqlite3VdbeAddOp(v, OP_Next, ephemTab, addr);
sqlite3VdbeAddOp(v, OP_Close, ephemTab, 0);
/* Cleanup */
sqlite3SelectDelete(pSelect);
}