/*
** Generate bytecode that does an UPDATE as part of an upsert.
**
** If pIdx is NULL, then the UNIQUE constraint that failed was the IPK.
** In this case parameter iCur is a cursor open on the table b-tree that
** currently points to the conflicting table row. Otherwise, if pIdx
** is not NULL, then pIdx is the constraint that failed and iCur is a
** cursor points to the conflicting row.
*/
void sqlite3UpsertDoUpdate(
Parse *pParse, /* The parsing and code-generating context */
Upsert *pUpsert, /* The ON CONFLICT clause for the upsert */
Table *pTab, /* The table being updated */
Index *pIdx, /* The UNIQUE constraint that failed */
int iCur /* Cursor for pIdx (or pTab if pIdx==NULL) */
){
Vdbe *v = pParse->pVdbe;
sqlite3 *db = pParse->db;
SrcList *pSrc; /* FROM clause for the UPDATE */
int iDataCur;
assert( v!=0 );
assert( pUpsert!=0 );
VdbeNoopComment((v, "Begin DO UPDATE of UPSERT"));
iDataCur = pUpsert->iDataCur;
if( pIdx && iCur!=iDataCur ){
if( HasRowid(pTab) ){
int regRowid = sqlite3GetTempReg(pParse);
sqlite3VdbeAddOp2(v, OP_IdxRowid, iCur, regRowid);
sqlite3VdbeAddOp3(v, OP_SeekRowid, iDataCur, 0, regRowid);
VdbeCoverage(v);
sqlite3ReleaseTempReg(pParse, regRowid);
}else{
Index *pPk = sqlite3PrimaryKeyIndex(pTab);
int nPk = pPk->nKeyCol;
int iPk = pParse->nMem+1;
int i;
pParse->nMem += nPk;
for(i=0; i<nPk; i++){
int k;
assert( pPk->aiColumn[i]>=0 );
k = sqlite3ColumnOfIndex(pIdx, pPk->aiColumn[i]);
sqlite3VdbeAddOp3(v, OP_Column, iCur, k, iPk+i);
VdbeComment((v, "%s.%s", pIdx->zName,
pTab->aCol[pPk->aiColumn[i]].zName));
}
sqlite3VdbeVerifyAbortable(v, OE_Abort);
i = sqlite3VdbeAddOp4Int(v, OP_Found, iDataCur, 0, iPk, nPk);
VdbeCoverage(v);
sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CORRUPT, OE_Abort, 0,
"corrupt database", P4_STATIC);
sqlite3VdbeJumpHere(v, i);
}
}
/* pUpsert does not own pUpsertSrc - the outer INSERT statement does. So
** we have to make a copy before passing it down into sqlite3Update() */
pSrc = sqlite3SrcListDup(db, pUpsert->pUpsertSrc, 0);
sqlite3Update(pParse, pSrc, pUpsert->pUpsertSet,
pUpsert->pUpsertWhere, OE_Abort, 0, 0, pUpsert);
pUpsert->pUpsertSet = 0; /* Will have been deleted by sqlite3Update() */
pUpsert->pUpsertWhere = 0; /* Will have been deleted by sqlite3Update() */
VdbeNoopComment((v, "End DO UPDATE of UPSERT"));
}
/*
** This function is called to generate code that runs when table pTab is
** being dropped from the database. The SrcList passed as the second argument
** to this function contains a single entry guaranteed to resolve to
** table pTab.
**
** Normally, no code is required. However, if either
**
** (a) The table is the parent table of a FK constraint, or
** (b) The table is the child table of a deferred FK constraint and it is
** determined at runtime that there are outstanding deferred FK
** constraint violations in the database,
**
** then the equivalent of "DELETE FROM <tbl>" is executed before dropping
** the table from the database. Triggers are disabled while running this
** DELETE, but foreign key actions are not.
*/
void sqlite3FkDropTable(Parse *pParse, SrcList *pName, Table *pTab){
sqlite3 *db = pParse->db;
if( (db->flags&SQLITE_ForeignKeys) && !IsVirtual(pTab) && !pTab->pSelect ){
int iSkip = 0;
Vdbe *v = sqlite3GetVdbe(pParse);
assert( v ); /* VDBE has already been allocated */
if( sqlite3FkReferences(pTab)==0 ){
/* Search for a deferred foreign key constraint for which this table
** is the child table. If one cannot be found, return without
** generating any VDBE code. If one can be found, then jump over
** the entire DELETE if there are no outstanding deferred constraints
** when this statement is run. */
FKey *p;
for(p=pTab->pFKey; p; p=p->pNextFrom){
if( p->isDeferred ) break;
}
if( !p ) return;
iSkip = sqlite3VdbeMakeLabel(v);
sqlite3VdbeAddOp2(v, OP_FkIfZero, 1, iSkip);
}
pParse->disableTriggers = 1;
sqlite3DeleteFrom(pParse, sqlite3SrcListDup(db, pName, 0), 0);
pParse->disableTriggers = 0;
/* If the DELETE has generated immediate foreign key constraint
** violations, halt the VDBE and return an error at this point, before
** any modifications to the schema are made. This is because statement
** transactions are not able to rollback schema changes. */
sqlite3VdbeAddOp2(v, OP_FkIfZero, 0, sqlite3VdbeCurrentAddr(v)+2);
sqlite3HaltConstraint(
pParse, OE_Abort, "foreign key constraint failed", P4_STATIC
);
if( iSkip ){
sqlite3VdbeResolveLabel(v, iSkip);
}
}
}
/*
** 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;
}
