diff -r 000000000000 -r 08ec8eefde2f persistentstorage/sql/SQLite364/resolve.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/persistentstorage/sql/SQLite364/resolve.c Fri Jan 22 11:06:30 2010 +0200 @@ -0,0 +1,1168 @@ +/* +** 2008 August 18 +** +** The author disclaims copyright to this source code. In place of +** a legal notice, here is a blessing: +** +** May you do good and not evil. +** May you find forgiveness for yourself and forgive others. +** May you share freely, never taking more than you give. +** +************************************************************************* +** +** This file contains routines used for walking the parser tree and +** resolve all identifiers by associating them with a particular +** table and column. +** +** $Id: resolve.c,v 1.9 2008/10/11 16:47:36 drh Exp $ +*/ +#include "sqliteInt.h" +#include +#include + +/* +** Turn the pExpr expression into an alias for the iCol-th column of the +** result set in pEList. +** +** If the result set column is a simple column reference, then this routine +** makes an exact copy. But for any other kind of expression, this +** routine make a copy of the result set column as the argument to the +** TK_AS operator. The TK_AS operator causes the expression to be +** evaluated just once and then reused for each alias. +** +** The reason for suppressing the TK_AS term when the expression is a simple +** column reference is so that the column reference will be recognized as +** usable by indices within the WHERE clause processing logic. +** +** Hack: The TK_AS operator is inhibited if zType[0]=='G'. This means +** that in a GROUP BY clause, the expression is evaluated twice. Hence: +** +** SELECT random()%5 AS x, count(*) FROM tab GROUP BY x +** +** Is equivalent to: +** +** SELECT random()%5 AS x, count(*) FROM tab GROUP BY random()%5 +** +** The result of random()%5 in the GROUP BY clause is probably different +** from the result in the result-set. We might fix this someday. Or +** then again, we might not... +*/ +static void resolveAlias( + Parse *pParse, /* Parsing context */ + ExprList *pEList, /* A result set */ + int iCol, /* A column in the result set. 0..pEList->nExpr-1 */ + Expr *pExpr, /* Transform this into an alias to the result set */ + const char *zType /* "GROUP" or "ORDER" or "" */ +){ + Expr *pOrig; /* The iCol-th column of the result set */ + Expr *pDup; /* Copy of pOrig */ + sqlite3 *db; /* The database connection */ + + assert( iCol>=0 && iColnExpr ); + pOrig = pEList->a[iCol].pExpr; + assert( pOrig!=0 ); + assert( pOrig->flags & EP_Resolved ); + db = pParse->db; + pDup = sqlite3ExprDup(db, pOrig); + if( pDup==0 ) return; + if( pDup->op!=TK_COLUMN && zType[0]!='G' ){ + pDup = sqlite3PExpr(pParse, TK_AS, pDup, 0, 0); + if( pDup==0 ) return; + if( pEList->a[iCol].iAlias==0 ){ + pEList->a[iCol].iAlias = ++pParse->nAlias; + } + pDup->iTable = pEList->a[iCol].iAlias; + } + if( pExpr->flags & EP_ExpCollate ){ + pDup->pColl = pExpr->pColl; + pDup->flags |= EP_ExpCollate; + } + sqlite3ExprClear(db, pExpr); + memcpy(pExpr, pDup, sizeof(*pExpr)); + sqlite3DbFree(db, pDup); +} + +/* +** Given the name of a column of the form X.Y.Z or Y.Z or just Z, look up +** that name in the set of source tables in pSrcList and make the pExpr +** expression node refer back to that source column. The following changes +** are made to pExpr: +** +** pExpr->iDb Set the index in db->aDb[] of the database X +** (even if X is implied). +** pExpr->iTable Set to the cursor number for the table obtained +** from pSrcList. +** pExpr->pTab Points to the Table structure of X.Y (even if +** X and/or Y are implied.) +** pExpr->iColumn Set to the column number within the table. +** pExpr->op Set to TK_COLUMN. +** pExpr->pLeft Any expression this points to is deleted +** pExpr->pRight Any expression this points to is deleted. +** +** The pDbToken is the name of the database (the "X"). This value may be +** NULL meaning that name is of the form Y.Z or Z. Any available database +** can be used. The pTableToken is the name of the table (the "Y"). This +** value can be NULL if pDbToken is also NULL. If pTableToken is NULL it +** means that the form of the name is Z and that columns from any table +** can be used. +** +** If the name cannot be resolved unambiguously, leave an error message +** in pParse and return non-zero. Return zero on success. +*/ +static int lookupName( + Parse *pParse, /* The parsing context */ + Token *pDbToken, /* Name of the database containing table, or NULL */ + Token *pTableToken, /* Name of table containing column, or NULL */ + Token *pColumnToken, /* Name of the column. */ + NameContext *pNC, /* The name context used to resolve the name */ + Expr *pExpr /* Make this EXPR node point to the selected column */ +){ + char *zDb = 0; /* Name of the database. The "X" in X.Y.Z */ + char *zTab = 0; /* Name of the table. The "Y" in X.Y.Z or Y.Z */ + char *zCol = 0; /* Name of the column. The "Z" */ + int i, j; /* Loop counters */ + int cnt = 0; /* Number of matching column names */ + int cntTab = 0; /* Number of matching table names */ + sqlite3 *db = pParse->db; /* The database connection */ + struct SrcList_item *pItem; /* Use for looping over pSrcList items */ + struct SrcList_item *pMatch = 0; /* The matching pSrcList item */ + NameContext *pTopNC = pNC; /* First namecontext in the list */ + Schema *pSchema = 0; /* Schema of the expression */ + + assert( pColumnToken && pColumnToken->z ); /* The Z in X.Y.Z cannot be NULL */ + + /* Dequote and zero-terminate the names */ + zDb = sqlite3NameFromToken(db, pDbToken); + zTab = sqlite3NameFromToken(db, pTableToken); + zCol = sqlite3NameFromToken(db, pColumnToken); + if( db->mallocFailed ){ + goto lookupname_end; + } + + /* Initialize the node to no-match */ + pExpr->iTable = -1; + pExpr->pTab = 0; + + /* Start at the inner-most context and move outward until a match is found */ + while( pNC && cnt==0 ){ + ExprList *pEList; + SrcList *pSrcList = pNC->pSrcList; + + if( pSrcList ){ + for(i=0, pItem=pSrcList->a; inSrc; i++, pItem++){ + Table *pTab; + int iDb; + Column *pCol; + + pTab = pItem->pTab; + assert( pTab!=0 && pTab->zName!=0 ); + iDb = sqlite3SchemaToIndex(db, pTab->pSchema); + assert( pTab->nCol>0 ); + if( zTab ){ + if( pItem->zAlias ){ + char *zTabName = pItem->zAlias; + if( sqlite3StrICmp(zTabName, zTab)!=0 ) continue; + }else{ + char *zTabName = pTab->zName; + if( zTabName==0 || sqlite3StrICmp(zTabName, zTab)!=0 ) continue; + if( zDb!=0 && sqlite3StrICmp(db->aDb[iDb].zName, zDb)!=0 ){ + continue; + } + } + } + if( 0==(cntTab++) ){ + pExpr->iTable = pItem->iCursor; + pExpr->pTab = pTab; + pSchema = pTab->pSchema; + pMatch = pItem; + } + for(j=0, pCol=pTab->aCol; jnCol; j++, pCol++){ + if( sqlite3StrICmp(pCol->zName, zCol)==0 ){ + IdList *pUsing; + cnt++; + pExpr->iTable = pItem->iCursor; + pExpr->pTab = pTab; + pMatch = pItem; + pSchema = pTab->pSchema; + /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */ + pExpr->iColumn = j==pTab->iPKey ? -1 : j; + if( inSrc-1 ){ + if( pItem[1].jointype & JT_NATURAL ){ + /* If this match occurred in the left table of a natural join, + ** then skip the right table to avoid a duplicate match */ + pItem++; + i++; + }else if( (pUsing = pItem[1].pUsing)!=0 ){ + /* If this match occurs on a column that is in the USING clause + ** of a join, skip the search of the right table of the join + ** to avoid a duplicate match there. */ + int k; + for(k=0; knId; k++){ + if( sqlite3StrICmp(pUsing->a[k].zName, zCol)==0 ){ + pItem++; + i++; + break; + } + } + } + } + break; + } + } + } + } + +#ifndef SQLITE_OMIT_TRIGGER + /* If we have not already resolved the name, then maybe + ** it is a new.* or old.* trigger argument reference + */ + if( zDb==0 && zTab!=0 && cnt==0 && pParse->trigStack!=0 ){ + TriggerStack *pTriggerStack = pParse->trigStack; + Table *pTab = 0; + u32 *piColMask; + if( pTriggerStack->newIdx != -1 && sqlite3StrICmp("new", zTab) == 0 ){ + pExpr->iTable = pTriggerStack->newIdx; + assert( pTriggerStack->pTab ); + pTab = pTriggerStack->pTab; + piColMask = &(pTriggerStack->newColMask); + }else if( pTriggerStack->oldIdx != -1 && sqlite3StrICmp("old", zTab)==0 ){ + pExpr->iTable = pTriggerStack->oldIdx; + assert( pTriggerStack->pTab ); + pTab = pTriggerStack->pTab; + piColMask = &(pTriggerStack->oldColMask); + } + + if( pTab ){ + int iCol; + Column *pCol = pTab->aCol; + + pSchema = pTab->pSchema; + cntTab++; + for(iCol=0; iCol < pTab->nCol; iCol++, pCol++) { + if( sqlite3StrICmp(pCol->zName, zCol)==0 ){ + cnt++; + pExpr->iColumn = iCol==pTab->iPKey ? -1 : iCol; + pExpr->pTab = pTab; + if( iCol>=0 ){ + testcase( iCol==31 ); + testcase( iCol==32 ); + *piColMask |= ((u32)1<=32?0xffffffff:0); + } + break; + } + } + } + } +#endif /* !defined(SQLITE_OMIT_TRIGGER) */ + + /* + ** Perhaps the name is a reference to the ROWID + */ + if( cnt==0 && cntTab==1 && sqlite3IsRowid(zCol) ){ + cnt = 1; + pExpr->iColumn = -1; + pExpr->affinity = SQLITE_AFF_INTEGER; + } + + /* + ** If the input is of the form Z (not Y.Z or X.Y.Z) then the name Z + ** might refer to an result-set alias. This happens, for example, when + ** we are resolving names in the WHERE clause of the following command: + ** + ** SELECT a+b AS x FROM table WHERE x<10; + ** + ** In cases like this, replace pExpr with a copy of the expression that + ** forms the result set entry ("a+b" in the example) and return immediately. + ** Note that the expression in the result set should have already been + ** resolved by the time the WHERE clause is resolved. + */ + if( cnt==0 && (pEList = pNC->pEList)!=0 && zTab==0 ){ + for(j=0; jnExpr; j++){ + char *zAs = pEList->a[j].zName; + if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){ + Expr *pOrig; + assert( pExpr->pLeft==0 && pExpr->pRight==0 ); + assert( pExpr->pList==0 ); + assert( pExpr->pSelect==0 ); + pOrig = pEList->a[j].pExpr; + if( !pNC->allowAgg && ExprHasProperty(pOrig, EP_Agg) ){ + sqlite3ErrorMsg(pParse, "misuse of aliased aggregate %s", zAs); + sqlite3DbFree(db, zCol); + return 2; + } + resolveAlias(pParse, pEList, j, pExpr, ""); + cnt = 1; + pMatch = 0; + assert( zTab==0 && zDb==0 ); + goto lookupname_end_2; + } + } + } + + /* Advance to the next name context. The loop will exit when either + ** we have a match (cnt>0) or when we run out of name contexts. + */ + if( cnt==0 ){ + pNC = pNC->pNext; + } + } + + /* + ** If X and Y are NULL (in other words if only the column name Z is + ** supplied) and the value of Z is enclosed in double-quotes, then + ** Z is a string literal if it doesn't match any column names. In that + ** case, we need to return right away and not make any changes to + ** pExpr. + ** + ** Because no reference was made to outer contexts, the pNC->nRef + ** fields are not changed in any context. + */ + if( cnt==0 && zTab==0 && pColumnToken->z[0]=='"' ){ + sqlite3DbFree(db, zCol); + pExpr->op = TK_STRING; + return 0; + } + + /* + ** cnt==0 means there was not match. cnt>1 means there were two or + ** more matches. Either way, we have an error. + */ + if( cnt!=1 ){ + const char *zErr; + zErr = cnt==0 ? "no such column" : "ambiguous column name"; + if( zDb ){ + sqlite3ErrorMsg(pParse, "%s: %s.%s.%s", zErr, zDb, zTab, zCol); + }else if( zTab ){ + sqlite3ErrorMsg(pParse, "%s: %s.%s", zErr, zTab, zCol); + }else{ + sqlite3ErrorMsg(pParse, "%s: %s", zErr, zCol); + } + pTopNC->nErr++; + } + + /* If a column from a table in pSrcList is referenced, then record + ** this fact in the pSrcList.a[].colUsed bitmask. Column 0 causes + ** bit 0 to be set. Column 1 sets bit 1. And so forth. If the + ** column number is greater than the number of bits in the bitmask + ** then set the high-order bit of the bitmask. + */ + if( pExpr->iColumn>=0 && pMatch!=0 ){ + int n = pExpr->iColumn; + testcase( n==sizeof(Bitmask)*8-1 ); + if( n>=sizeof(Bitmask)*8 ){ + n = sizeof(Bitmask)*8-1; + } + assert( pMatch->iCursor==pExpr->iTable ); + pMatch->colUsed |= ((Bitmask)1)<pLeft); + pExpr->pLeft = 0; + sqlite3ExprDelete(db, pExpr->pRight); + pExpr->pRight = 0; + pExpr->op = TK_COLUMN; +lookupname_end_2: + sqlite3DbFree(db, zCol); + if( cnt==1 ){ + assert( pNC!=0 ); + sqlite3AuthRead(pParse, pExpr, pSchema, pNC->pSrcList); + /* Increment the nRef value on all name contexts from TopNC up to + ** the point where the name matched. */ + for(;;){ + assert( pTopNC!=0 ); + pTopNC->nRef++; + if( pTopNC==pNC ) break; + pTopNC = pTopNC->pNext; + } + return 0; + } else { + return 1; + } +} + +/* +** This routine is callback for sqlite3WalkExpr(). +** +** Resolve symbolic names into TK_COLUMN operators for the current +** node in the expression tree. Return 0 to continue the search down +** the tree or 2 to abort the tree walk. +** +** This routine also does error checking and name resolution for +** function names. The operator for aggregate functions is changed +** to TK_AGG_FUNCTION. +*/ +static int resolveExprStep(Walker *pWalker, Expr *pExpr){ + NameContext *pNC; + Parse *pParse; + + pNC = pWalker->u.pNC; + assert( pNC!=0 ); + pParse = pNC->pParse; + assert( pParse==pWalker->pParse ); + + if( ExprHasAnyProperty(pExpr, EP_Resolved) ) return WRC_Prune; + ExprSetProperty(pExpr, EP_Resolved); +#ifndef NDEBUG + if( pNC->pSrcList && pNC->pSrcList->nAlloc>0 ){ + SrcList *pSrcList = pNC->pSrcList; + int i; + for(i=0; ipSrcList->nSrc; i++){ + assert( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursornTab); + } + } +#endif + switch( pExpr->op ){ + +#if defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY) + /* The special operator TK_ROW means use the rowid for the first + ** column in the FROM clause. This is used by the LIMIT and ORDER BY + ** clause processing on UPDATE and DELETE statements. + */ + case TK_ROW: { + SrcList *pSrcList = pNC->pSrcList; + struct SrcList_item *pItem; + assert( pSrcList && pSrcList->nSrc==1 ); + pItem = pSrcList->a; + pExpr->op = TK_COLUMN; + pExpr->pTab = pItem->pTab; + pExpr->iTable = pItem->iCursor; + pExpr->iColumn = -1; + pExpr->affinity = SQLITE_AFF_INTEGER; + break; + } +#endif /* defined(SQLITE_ENABLE_UPDATE_DELETE_LIMIT) && !defined(SQLITE_OMIT_SUBQUERY) */ + + /* A lone identifier is the name of a column. + */ + case TK_ID: { + lookupName(pParse, 0, 0, &pExpr->token, pNC, pExpr); + return WRC_Prune; + } + + /* A table name and column name: ID.ID + ** Or a database, table and column: ID.ID.ID + */ + case TK_DOT: { + Token *pColumn; + Token *pTable; + Token *pDb; + Expr *pRight; + + /* if( pSrcList==0 ) break; */ + pRight = pExpr->pRight; + if( pRight->op==TK_ID ){ + pDb = 0; + pTable = &pExpr->pLeft->token; + pColumn = &pRight->token; + }else{ + assert( pRight->op==TK_DOT ); + pDb = &pExpr->pLeft->token; + pTable = &pRight->pLeft->token; + pColumn = &pRight->pRight->token; + } + lookupName(pParse, pDb, pTable, pColumn, pNC, pExpr); + return WRC_Prune; + } + + /* Resolve function names + */ + case TK_CONST_FUNC: + case TK_FUNCTION: { + ExprList *pList = pExpr->pList; /* The argument list */ + int n = pList ? pList->nExpr : 0; /* Number of arguments */ + int no_such_func = 0; /* True if no such function exists */ + int wrong_num_args = 0; /* True if wrong number of arguments */ + int is_agg = 0; /* True if is an aggregate function */ + int auth; /* Authorization to use the function */ + int nId; /* Number of characters in function name */ + const char *zId; /* The function name. */ + FuncDef *pDef; /* Information about the function */ + int enc = ENC(pParse->db); /* The database encoding */ + + zId = (char*)pExpr->token.z; + nId = pExpr->token.n; + pDef = sqlite3FindFunction(pParse->db, zId, nId, n, enc, 0); + if( pDef==0 ){ + pDef = sqlite3FindFunction(pParse->db, zId, nId, -1, enc, 0); + if( pDef==0 ){ + no_such_func = 1; + }else{ + wrong_num_args = 1; + } + }else{ + is_agg = pDef->xFunc==0; + } +#ifndef SQLITE_OMIT_AUTHORIZATION + if( pDef ){ + auth = sqlite3AuthCheck(pParse, SQLITE_FUNCTION, 0, pDef->zName, 0); + if( auth!=SQLITE_OK ){ + if( auth==SQLITE_DENY ){ + sqlite3ErrorMsg(pParse, "not authorized to use function: %s", + pDef->zName); + pNC->nErr++; + } + pExpr->op = TK_NULL; + return WRC_Prune; + } + } +#endif + if( is_agg && !pNC->allowAgg ){ + sqlite3ErrorMsg(pParse, "misuse of aggregate function %.*s()", nId,zId); + pNC->nErr++; + is_agg = 0; + }else if( no_such_func ){ + sqlite3ErrorMsg(pParse, "no such function: %.*s", nId, zId); + pNC->nErr++; + }else if( wrong_num_args ){ + sqlite3ErrorMsg(pParse,"wrong number of arguments to function %.*s()", + nId, zId); + pNC->nErr++; + } + if( is_agg ){ + pExpr->op = TK_AGG_FUNCTION; + pNC->hasAgg = 1; + } + if( is_agg ) pNC->allowAgg = 0; + sqlite3WalkExprList(pWalker, pList); + if( is_agg ) pNC->allowAgg = 1; + /* FIX ME: Compute pExpr->affinity based on the expected return + ** type of the function + */ + return WRC_Prune; + } +#ifndef SQLITE_OMIT_SUBQUERY + case TK_SELECT: + case TK_EXISTS: +#endif + case TK_IN: { + if( pExpr->pSelect ){ + int nRef = pNC->nRef; +#ifndef SQLITE_OMIT_CHECK + if( pNC->isCheck ){ + sqlite3ErrorMsg(pParse,"subqueries prohibited in CHECK constraints"); + } +#endif + sqlite3WalkSelect(pWalker, pExpr->pSelect); + assert( pNC->nRef>=nRef ); + if( nRef!=pNC->nRef ){ + ExprSetProperty(pExpr, EP_VarSelect); + } + } + break; + } +#ifndef SQLITE_OMIT_CHECK + case TK_VARIABLE: { + if( pNC->isCheck ){ + sqlite3ErrorMsg(pParse,"parameters prohibited in CHECK constraints"); + } + break; + } +#endif + } + return (pParse->nErr || pParse->db->mallocFailed) ? WRC_Abort : WRC_Continue; +} + +/* +** pEList is a list of expressions which are really the result set of the +** a SELECT statement. pE is a term in an ORDER BY or GROUP BY clause. +** This routine checks to see if pE is a simple identifier which corresponds +** to the AS-name of one of the terms of the expression list. If it is, +** this routine return an integer between 1 and N where N is the number of +** elements in pEList, corresponding to the matching entry. If there is +** no match, or if pE is not a simple identifier, then this routine +** return 0. +** +** pEList has been resolved. pE has not. +*/ +static int resolveAsName( + Parse *pParse, /* Parsing context for error messages */ + ExprList *pEList, /* List of expressions to scan */ + Expr *pE /* Expression we are trying to match */ +){ + int i; /* Loop counter */ + + if( pE->op==TK_ID || (pE->op==TK_STRING && pE->token.z[0]!='\'') ){ + sqlite3 *db = pParse->db; + char *zCol = sqlite3NameFromToken(db, &pE->token); + if( zCol==0 ){ + return -1; + } + for(i=0; inExpr; i++){ + char *zAs = pEList->a[i].zName; + if( zAs!=0 && sqlite3StrICmp(zAs, zCol)==0 ){ + sqlite3DbFree(db, zCol); + return i+1; + } + } + sqlite3DbFree(db, zCol); + } + return 0; +} + +/* +** pE is a pointer to an expression which is a single term in the +** ORDER BY of a compound SELECT. The expression has not been +** name resolved. +** +** At the point this routine is called, we already know that the +** ORDER BY term is not an integer index into the result set. That +** case is handled by the calling routine. +** +** Attempt to match pE against result set columns in the left-most +** SELECT statement. Return the index i of the matching column, +** as an indication to the caller that it should sort by the i-th column. +** The left-most column is 1. In other words, the value returned is the +** same integer value that would be used in the SQL statement to indicate +** the column. +** +** If there is no match, return 0. Return -1 if an error occurs. +*/ +static int resolveOrderByTermToExprList( + Parse *pParse, /* Parsing context for error messages */ + Select *pSelect, /* The SELECT statement with the ORDER BY clause */ + Expr *pE /* The specific ORDER BY term */ +){ + int i; /* Loop counter */ + ExprList *pEList; /* The columns of the result set */ + NameContext nc; /* Name context for resolving pE */ + + assert( sqlite3ExprIsInteger(pE, &i)==0 ); + pEList = pSelect->pEList; + + /* Resolve all names in the ORDER BY term expression + */ + memset(&nc, 0, sizeof(nc)); + nc.pParse = pParse; + nc.pSrcList = pSelect->pSrc; + nc.pEList = pEList; + nc.allowAgg = 1; + nc.nErr = 0; + if( sqlite3ResolveExprNames(&nc, pE) ){ + sqlite3ErrorClear(pParse); + return 0; + } + + /* Try to match the ORDER BY expression against an expression + ** in the result set. Return an 1-based index of the matching + ** result-set entry. + */ + for(i=0; inExpr; i++){ + if( sqlite3ExprCompare(pEList->a[i].pExpr, pE) ){ + return i+1; + } + } + + /* If no match, return 0. */ + return 0; +} + +/* +** Generate an ORDER BY or GROUP BY term out-of-range error. +*/ +static void resolveOutOfRangeError( + Parse *pParse, /* The error context into which to write the error */ + const char *zType, /* "ORDER" or "GROUP" */ + int i, /* The index (1-based) of the term out of range */ + int mx /* Largest permissible value of i */ +){ + sqlite3ErrorMsg(pParse, + "%r %s BY term out of range - should be " + "between 1 and %d", i, zType, mx); +} + +/* +** Analyze the ORDER BY clause in a compound SELECT statement. Modify +** each term of the ORDER BY clause is a constant integer between 1 +** and N where N is the number of columns in the compound SELECT. +** +** ORDER BY terms that are already an integer between 1 and N are +** unmodified. ORDER BY terms that are integers outside the range of +** 1 through N generate an error. ORDER BY terms that are expressions +** are matched against result set expressions of compound SELECT +** beginning with the left-most SELECT and working toward the right. +** At the first match, the ORDER BY expression is transformed into +** the integer column number. +** +** Return the number of errors seen. +*/ +static int resolveCompoundOrderBy( + Parse *pParse, /* Parsing context. Leave error messages here */ + Select *pSelect /* The SELECT statement containing the ORDER BY */ +){ + int i; + ExprList *pOrderBy; + ExprList *pEList; + sqlite3 *db; + int moreToDo = 1; + + pOrderBy = pSelect->pOrderBy; + if( pOrderBy==0 ) return 0; + db = pParse->db; +#if SQLITE_MAX_COLUMN + if( pOrderBy->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){ + sqlite3ErrorMsg(pParse, "too many terms in ORDER BY clause"); + return 1; + } +#endif + for(i=0; inExpr; i++){ + pOrderBy->a[i].done = 0; + } + pSelect->pNext = 0; + while( pSelect->pPrior ){ + pSelect->pPrior->pNext = pSelect; + pSelect = pSelect->pPrior; + } + while( pSelect && moreToDo ){ + struct ExprList_item *pItem; + moreToDo = 0; + pEList = pSelect->pEList; + assert( pEList!=0 ); + for(i=0, pItem=pOrderBy->a; inExpr; i++, pItem++){ + int iCol = -1; + Expr *pE, *pDup; + if( pItem->done ) continue; + pE = pItem->pExpr; + if( sqlite3ExprIsInteger(pE, &iCol) ){ + if( iCol<0 || iCol>pEList->nExpr ){ + resolveOutOfRangeError(pParse, "ORDER", i+1, pEList->nExpr); + return 1; + } + }else{ + iCol = resolveAsName(pParse, pEList, pE); + if( iCol==0 ){ + pDup = sqlite3ExprDup(db, pE); + if( !db->mallocFailed ){ + assert(pDup); + iCol = resolveOrderByTermToExprList(pParse, pSelect, pDup); + } + sqlite3ExprDelete(db, pDup); + } + if( iCol<0 ){ + return 1; + } + } + if( iCol>0 ){ + CollSeq *pColl = pE->pColl; + int flags = pE->flags & EP_ExpCollate; + sqlite3ExprDelete(db, pE); + pItem->pExpr = pE = sqlite3Expr(db, TK_INTEGER, 0, 0, 0); + if( pE==0 ) return 1; + pE->pColl = pColl; + pE->flags |= EP_IntValue | flags; + pE->iTable = iCol; + pItem->iCol = iCol; + pItem->done = 1; + }else{ + moreToDo = 1; + } + } + pSelect = pSelect->pNext; + } + for(i=0; inExpr; i++){ + if( pOrderBy->a[i].done==0 ){ + sqlite3ErrorMsg(pParse, "%r ORDER BY term does not match any " + "column in the result set", i+1); + return 1; + } + } + return 0; +} + +/* +** Check every term in the ORDER BY or GROUP BY clause pOrderBy of +** the SELECT statement pSelect. If any term is reference to a +** result set expression (as determined by the ExprList.a.iCol field) +** then convert that term into a copy of the corresponding result set +** column. +** +** If any errors are detected, add an error message to pParse and +** return non-zero. Return zero if no errors are seen. +*/ +int sqlite3ResolveOrderGroupBy( + Parse *pParse, /* Parsing context. Leave error messages here */ + Select *pSelect, /* The SELECT statement containing the clause */ + ExprList *pOrderBy, /* The ORDER BY or GROUP BY clause to be processed */ + const char *zType /* "ORDER" or "GROUP" */ +){ + int i; + sqlite3 *db = pParse->db; + ExprList *pEList; + struct ExprList_item *pItem; + + if( pOrderBy==0 || pParse->db->mallocFailed ) return 0; +#if SQLITE_MAX_COLUMN + if( pOrderBy->nExpr>db->aLimit[SQLITE_LIMIT_COLUMN] ){ + sqlite3ErrorMsg(pParse, "too many terms in %s BY clause", zType); + return 1; + } +#endif + pEList = pSelect->pEList; + assert( pEList!=0 ); /* sqlite3SelectNew() guarantees this */ + for(i=0, pItem=pOrderBy->a; inExpr; i++, pItem++){ + if( pItem->iCol ){ + if( pItem->iCol>pEList->nExpr ){ + resolveOutOfRangeError(pParse, zType, i+1, pEList->nExpr); + return 1; + } + resolveAlias(pParse, pEList, pItem->iCol-1, pItem->pExpr, zType); + } + } + return 0; +} + +/* +** pOrderBy is an ORDER BY or GROUP BY clause in SELECT statement pSelect. +** The Name context of the SELECT statement is pNC. zType is either +** "ORDER" or "GROUP" depending on which type of clause pOrderBy is. +** +** This routine resolves each term of the clause into an expression. +** If the order-by term is an integer I between 1 and N (where N is the +** number of columns in the result set of the SELECT) then the expression +** in the resolution is a copy of the I-th result-set expression. If +** the order-by term is an identify that corresponds to the AS-name of +** a result-set expression, then the term resolves to a copy of the +** result-set expression. Otherwise, the expression is resolved in +** the usual way - using sqlite3ResolveExprNames(). +** +** This routine returns the number of errors. If errors occur, then +** an appropriate error message might be left in pParse. (OOM errors +** excepted.) +*/ +static int resolveOrderGroupBy( + NameContext *pNC, /* The name context of the SELECT statement */ + Select *pSelect, /* The SELECT statement holding pOrderBy */ + ExprList *pOrderBy, /* An ORDER BY or GROUP BY clause to resolve */ + const char *zType /* Either "ORDER" or "GROUP", as appropriate */ +){ + int i; /* Loop counter */ + int iCol; /* Column number */ + struct ExprList_item *pItem; /* A term of the ORDER BY clause */ + Parse *pParse; /* Parsing context */ + int nResult; /* Number of terms in the result set */ + + if( pOrderBy==0 ) return 0; + nResult = pSelect->pEList->nExpr; + pParse = pNC->pParse; + for(i=0, pItem=pOrderBy->a; inExpr; i++, pItem++){ + Expr *pE = pItem->pExpr; + iCol = resolveAsName(pParse, pSelect->pEList, pE); + if( iCol<0 ){ + return 1; /* OOM error */ + } + if( iCol>0 ){ + /* If an AS-name match is found, mark this ORDER BY column as being + ** a copy of the iCol-th result-set column. The subsequent call to + ** sqlite3ResolveOrderGroupBy() will convert the expression to a + ** copy of the iCol-th result-set expression. */ + pItem->iCol = iCol; + continue; + } + if( sqlite3ExprIsInteger(pE, &iCol) ){ + /* The ORDER BY term is an integer constant. Again, set the column + ** number so that sqlite3ResolveOrderGroupBy() will convert the + ** order-by term to a copy of the result-set expression */ + if( iCol<1 ){ + resolveOutOfRangeError(pParse, zType, i+1, nResult); + return 1; + } + pItem->iCol = iCol; + continue; + } + + /* Otherwise, treat the ORDER BY term as an ordinary expression */ + pItem->iCol = 0; + if( sqlite3ResolveExprNames(pNC, pE) ){ + return 1; + } + } + return sqlite3ResolveOrderGroupBy(pParse, pSelect, pOrderBy, zType); +} + +/* +** Resolve names in the SELECT statement p and all of its descendents. +*/ +static int resolveSelectStep(Walker *pWalker, Select *p){ + NameContext *pOuterNC; /* Context that contains this SELECT */ + NameContext sNC; /* Name context of this SELECT */ + int isCompound; /* True if p is a compound select */ + int nCompound; /* Number of compound terms processed so far */ + Parse *pParse; /* Parsing context */ + ExprList *pEList; /* Result set expression list */ + int i; /* Loop counter */ + ExprList *pGroupBy; /* The GROUP BY clause */ + Select *pLeftmost; /* Left-most of SELECT of a compound */ + sqlite3 *db; /* Database connection */ + + + assert( p!=0 ); + if( p->selFlags & SF_Resolved ){ + return WRC_Prune; + } + pOuterNC = pWalker->u.pNC; + pParse = pWalker->pParse; + db = pParse->db; + + /* Normally sqlite3SelectExpand() will be called first and will have + ** already expanded this SELECT. However, if this is a subquery within + ** an expression, sqlite3ResolveExprNames() will be called without a + ** prior call to sqlite3SelectExpand(). When that happens, let + ** sqlite3SelectPrep() do all of the processing for this SELECT. + ** sqlite3SelectPrep() will invoke both sqlite3SelectExpand() and + ** this routine in the correct order. + */ + if( (p->selFlags & SF_Expanded)==0 ){ + sqlite3SelectPrep(pParse, p, pOuterNC); + return (pParse->nErr || db->mallocFailed) ? WRC_Abort : WRC_Prune; + } + + isCompound = p->pPrior!=0; + nCompound = 0; + pLeftmost = p; + while( p ){ + assert( (p->selFlags & SF_Expanded)!=0 ); + assert( (p->selFlags & SF_Resolved)==0 ); + p->selFlags |= SF_Resolved; + + /* Resolve the expressions in the LIMIT and OFFSET clauses. These + ** are not allowed to refer to any names, so pass an empty NameContext. + */ + memset(&sNC, 0, sizeof(sNC)); + sNC.pParse = pParse; + if( sqlite3ResolveExprNames(&sNC, p->pLimit) || + sqlite3ResolveExprNames(&sNC, p->pOffset) ){ + return WRC_Abort; + } + + /* Set up the local name-context to pass to sqlite3ResolveExprNames() to + ** resolve the result-set expression list. + */ + sNC.allowAgg = 1; + sNC.pSrcList = p->pSrc; + sNC.pNext = pOuterNC; + + /* Resolve names in the result set. */ + pEList = p->pEList; + assert( pEList!=0 ); + for(i=0; inExpr; i++){ + Expr *pX = pEList->a[i].pExpr; + if( sqlite3ResolveExprNames(&sNC, pX) ){ + return WRC_Abort; + } + } + + /* Recursively resolve names in all subqueries + */ + for(i=0; ipSrc->nSrc; i++){ + struct SrcList_item *pItem = &p->pSrc->a[i]; + if( pItem->pSelect ){ + const char *zSavedContext = pParse->zAuthContext; + if( pItem->zName ) pParse->zAuthContext = pItem->zName; + sqlite3ResolveSelectNames(pParse, pItem->pSelect, &sNC); + pParse->zAuthContext = zSavedContext; + if( pParse->nErr || db->mallocFailed ) return WRC_Abort; + } + } + + /* If there are no aggregate functions in the result-set, and no GROUP BY + ** expression, do not allow aggregates in any of the other expressions. + */ + assert( (p->selFlags & SF_Aggregate)==0 ); + pGroupBy = p->pGroupBy; + if( pGroupBy || sNC.hasAgg ){ + p->selFlags |= SF_Aggregate; + }else{ + sNC.allowAgg = 0; + } + + /* If a HAVING clause is present, then there must be a GROUP BY clause. + */ + if( p->pHaving && !pGroupBy ){ + sqlite3ErrorMsg(pParse, "a GROUP BY clause is required before HAVING"); + return WRC_Abort; + } + + /* Add the expression list to the name-context before parsing the + ** other expressions in the SELECT statement. This is so that + ** expressions in the WHERE clause (etc.) can refer to expressions by + ** aliases in the result set. + ** + ** Minor point: If this is the case, then the expression will be + ** re-evaluated for each reference to it. + */ + sNC.pEList = p->pEList; + if( sqlite3ResolveExprNames(&sNC, p->pWhere) || + sqlite3ResolveExprNames(&sNC, p->pHaving) + ){ + return WRC_Abort; + } + + /* The ORDER BY and GROUP BY clauses may not refer to terms in + ** outer queries + */ + sNC.pNext = 0; + sNC.allowAgg = 1; + + /* Process the ORDER BY clause for singleton SELECT statements. + ** The ORDER BY clause for compounds SELECT statements is handled + ** below, after all of the result-sets for all of the elements of + ** the compound have been resolved. + */ + if( !isCompound && resolveOrderGroupBy(&sNC, p, p->pOrderBy, "ORDER") ){ + return WRC_Abort; + } + if( db->mallocFailed ){ + return WRC_Abort; + } + + /* Resolve the GROUP BY clause. At the same time, make sure + ** the GROUP BY clause does not contain aggregate functions. + */ + if( pGroupBy ){ + struct ExprList_item *pItem; + + if( resolveOrderGroupBy(&sNC, p, pGroupBy, "GROUP") || db->mallocFailed ){ + return WRC_Abort; + } + for(i=0, pItem=pGroupBy->a; inExpr; i++, pItem++){ + if( ExprHasProperty(pItem->pExpr, EP_Agg) ){ + sqlite3ErrorMsg(pParse, "aggregate functions are not allowed in " + "the GROUP BY clause"); + return WRC_Abort; + } + } + } + + /* Advance to the next term of the compound + */ + p = p->pPrior; + nCompound++; + } + + /* Resolve the ORDER BY on a compound SELECT after all terms of + ** the compound have been resolved. + */ + if( isCompound && resolveCompoundOrderBy(pParse, pLeftmost) ){ + return WRC_Abort; + } + + return WRC_Prune; +} + +/* +** This routine walks an expression tree and resolves references to +** table columns and result-set columns. At the same time, do error +** checking on function usage and set a flag if any aggregate functions +** are seen. +** +** To resolve table columns references we look for nodes (or subtrees) of the +** form X.Y.Z or Y.Z or just Z where +** +** X: The name of a database. Ex: "main" or "temp" or +** the symbolic name assigned to an ATTACH-ed database. +** +** Y: The name of a table in a FROM clause. Or in a trigger +** one of the special names "old" or "new". +** +** Z: The name of a column in table Y. +** +** The node at the root of the subtree is modified as follows: +** +** Expr.op Changed to TK_COLUMN +** Expr.pTab Points to the Table object for X.Y +** Expr.iColumn The column index in X.Y. -1 for the rowid. +** Expr.iTable The VDBE cursor number for X.Y +** +** +** To resolve result-set references, look for expression nodes of the +** form Z (with no X and Y prefix) where the Z matches the right-hand +** size of an AS clause in the result-set of a SELECT. The Z expression +** is replaced by a copy of the left-hand side of the result-set expression. +** Table-name and function resolution occurs on the substituted expression +** tree. For example, in: +** +** SELECT a+b AS x, c+d AS y FROM t1 ORDER BY x; +** +** The "x" term of the order by is replaced by "a+b" to render: +** +** SELECT a+b AS x, c+d AS y FROM t1 ORDER BY a+b; +** +** Function calls are checked to make sure that the function is +** defined and that the correct number of arguments are specified. +** If the function is an aggregate function, then the pNC->hasAgg is +** set and the opcode is changed from TK_FUNCTION to TK_AGG_FUNCTION. +** If an expression contains aggregate functions then the EP_Agg +** property on the expression is set. +** +** An error message is left in pParse if anything is amiss. The number +** if errors is returned. +*/ +int sqlite3ResolveExprNames( + NameContext *pNC, /* Namespace to resolve expressions in. */ + Expr *pExpr /* The expression to be analyzed. */ +){ + int savedHasAgg; + Walker w; + + if( pExpr==0 ) return 0; +#if SQLITE_MAX_EXPR_DEPTH>0 + { + Parse *pParse = pNC->pParse; + if( sqlite3ExprCheckHeight(pParse, pExpr->nHeight+pNC->pParse->nHeight) ){ + return 1; + } + pParse->nHeight += pExpr->nHeight; + } +#endif + savedHasAgg = pNC->hasAgg; + pNC->hasAgg = 0; + w.xExprCallback = resolveExprStep; + w.xSelectCallback = resolveSelectStep; + w.pParse = pNC->pParse; + w.u.pNC = pNC; + sqlite3WalkExpr(&w, pExpr); +#if SQLITE_MAX_EXPR_DEPTH>0 + pNC->pParse->nHeight -= pExpr->nHeight; +#endif + if( pNC->nErr>0 ){ + ExprSetProperty(pExpr, EP_Error); + } + if( pNC->hasAgg ){ + ExprSetProperty(pExpr, EP_Agg); + }else if( savedHasAgg ){ + pNC->hasAgg = 1; + } + return ExprHasProperty(pExpr, EP_Error); +} + + +/* +** Resolve all names in all expressions of a SELECT and in all +** decendents of the SELECT, including compounds off of p->pPrior, +** subqueries in expressions, and subqueries used as FROM clause +** terms. +** +** See sqlite3ResolveExprNames() for a description of the kinds of +** transformations that occur. +** +** All SELECT statements should have been expanded using +** sqlite3SelectExpand() prior to invoking this routine. +*/ +void sqlite3ResolveSelectNames( + Parse *pParse, /* The parser context */ + Select *p, /* The SELECT statement being coded. */ + NameContext *pOuterNC /* Name context for parent SELECT statement */ +){ + Walker w; + + assert( p!=0 ); + w.xExprCallback = resolveExprStep; + w.xSelectCallback = resolveSelectStep; + w.pParse = pParse; + w.u.pNC = pOuterNC; + sqlite3WalkSelect(&w, p); +}