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Correctly handle self-referential foreign keys on WITHOUT ROWID tables.

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FossilOrigin-Name: af128862ab6008df9dda1ee90f93f9efd629e259
This commit is contained in:
drh
2013-11-04 13:56:00 +00:00
parent bd50a926ef
commit 90e758ff1f
3 changed files with 93 additions and 40 deletions
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119
src/fkey.c
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@@ -445,6 +445,62 @@ static void fkLookupParent(
sqlite3VdbeAddOp1(v, OP_Close, iCur);
}
/*
** Return an Expr object that refers to a memory register corresponding
** to column iCol of table pTab.
**
** regBase is the first of an array of register that contains the data
** for pTab. regBase itself holds the rowid. regBase+1 holds the first
** column. regBase+2 holds the second column, and so forth.
*/
static Expr *exprTableRegister(
Parse *pParse, /* Parsing and code generating context */
Table *pTab, /* The table whose content is at r[regBase]... */
int regBase, /* Contents of table pTab */
i16 iCol /* Which column of pTab is desired */
){
Expr *pExpr;
Column *pCol;
const char *zColl;
sqlite3 *db = pParse->db;
pExpr = sqlite3Expr(db, TK_REGISTER, 0);
if( pExpr ){
if( iCol>=0 && iCol!=pTab->iPKey ){
pCol = &pTab->aCol[iCol];
pExpr->iTable = regBase + iCol + 1;
pExpr->affinity = pCol->affinity;
zColl = pCol->zColl;
if( zColl==0 ) zColl = db->pDfltColl->zName;
pExpr = sqlite3ExprAddCollateString(pParse, pExpr, zColl);
}else{
pExpr->iTable = regBase;
pExpr->affinity = SQLITE_AFF_INTEGER;
}
}
return pExpr;
}
/*
** Return an Expr object that refers to column iCol of table pTab which
** has cursor iCur.
*/
static Expr *exprTableColumn(
sqlite3 *db, /* The database connection */
Table *pTab, /* The table whose column is desired */
int iCursor, /* The open cursor on the table */
i16 iCol /* The column that is wanted */
){
Expr *pExpr = sqlite3Expr(db, TK_COLUMN, 0);
if( pExpr ){
pExpr->pTab = pTab;
pExpr->iTable = iCursor;
pExpr->iColumn = iCol;
}
return pExpr;
}
/*
** This function is called to generate code executed when a row is deleted
** from the parent table of foreign key constraint pFKey and, if pFKey is
@@ -514,26 +570,8 @@ static void fkScanChildren(
i16 iCol; /* Index of column in child table */
const char *zCol; /* Name of column in child table */
pLeft = sqlite3Expr(db, TK_REGISTER, 0);
if( pLeft ){
/* Set the collation sequence and affinity of the LHS of each TK_EQ
** expression to the parent key column defaults. */
if( pIdx ){
Column *pCol;
const char *zColl;
iCol = pIdx->aiColumn[i];
pCol = &pTab->aCol[iCol];
if( pTab->iPKey==iCol ) iCol = -1;
pLeft->iTable = regData+iCol+1;
pLeft->affinity = pCol->affinity;
zColl = pCol->zColl;
if( zColl==0 ) zColl = db->pDfltColl->zName;
pLeft = sqlite3ExprAddCollateString(pParse, pLeft, zColl);
}else{
pLeft->iTable = regData;
pLeft->affinity = SQLITE_AFF_INTEGER;
}
}
iCol = pIdx ? pIdx->aiColumn[i] : -1;
pLeft = exprTableRegister(pParse, pTab, regData, iCol);
iCol = aiCol ? aiCol[i] : pFKey->aCol[0].iFrom;
assert( iCol>=0 );
zCol = pFKey->pFrom->aCol[iCol].zName;
@@ -542,23 +580,38 @@ static void fkScanChildren(
pWhere = sqlite3ExprAnd(db, pWhere, pEq);
}
/* If the child table is the same as the parent table, and this scan
** is taking place as part of a DELETE operation (operation D.2), omit the
** row being deleted from the scan by adding ($rowid != rowid) to the WHERE
** clause, where $rowid is the rowid of the row being deleted. */
if( pTab==pFKey->pFrom && nIncr>0 && HasRowid(pTab) /*FIXME*/ ){
/* If the child table is the same as the parent table, then add terms
** to the WHERE clause that prevent this entry from being scanned.
** The added WHERE clause terms are like this:
**
** $current_rowid!=rowid
** NOT( $current_a==a AND $current_b==b AND ... )
**
** The first form is used for rowid tables. The second form is used
** for WITHOUT ROWID tables. In the second form, the primary key is
** (a,b,...)
*/
if( pTab==pFKey->pFrom && nIncr>0 ){
Expr *pNe; /* Expression (pLeft != pRight) */
Expr *pLeft; /* Value from parent table row */
Expr *pRight; /* Column ref to child table */
pLeft = sqlite3Expr(db, TK_REGISTER, 0);
pRight = sqlite3Expr(db, TK_COLUMN, 0);
if( pLeft && pRight ){
pLeft->iTable = regData;
pLeft->affinity = SQLITE_AFF_INTEGER;
pRight->iTable = pSrc->a[0].iCursor;
pRight->iColumn = -1;
if( HasRowid(pTab) ){
pLeft = exprTableRegister(pParse, pTab, regData, -1);
pRight = exprTableColumn(db, pTab, pSrc->a[0].iCursor, -1);
pNe = sqlite3PExpr(pParse, TK_NE, pLeft, pRight, 0);
}else{
int i;
Expr *pEq, *pAll = 0;
Index *pPk = sqlite3PrimaryKeyIndex(pTab);
for(i=0; i<pPk->nKeyCol; i++){
i16 iCol = pIdx->aiColumn[i];
pLeft = exprTableRegister(pParse, pTab, regData, iCol);
pRight = exprTableColumn(db, pTab, pSrc->a[0].iCursor, iCol);
pEq = sqlite3PExpr(pParse, TK_EQ, pLeft, pRight, 0);
pAll = sqlite3ExprAnd(db, pAll, pEq);
}
pNe = sqlite3PExpr(pParse, TK_NOT, pAll, 0, 0);
}
pNe = sqlite3PExpr(pParse, TK_NE, pLeft, pRight, 0);
pWhere = sqlite3ExprAnd(db, pWhere, pNe);
}