** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
-** $Id: expr.c,v 1.106 2004/01/16 16:42:54 drh Exp $
+** $Id: expr.c,v 1.107 2004/01/25 22:44:59 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>
return 0;
}
+/*
+** 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 holding
+** the table.
+** pExpr->iTable Set to the cursor number for the table obtained
+** from pSrcList.
+** pExpr->iColumn Set to the column number within the table.
+** pExpr->dataType Set to the appropriate data type for the column.
+** 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. */
+ SrcList *pSrcList, /* List of tables used to resolve column names */
+ ExprList *pEList, /* List of expressions used to resolve "AS" */
+ 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 */
+ sqlite *db; /* The database */
+
+ assert( pColumnToken && pColumnToken->z ); /* The Z in X.Y.Z cannot be NULL */
+ if( pDbToken && pDbToken->z ){
+ zDb = sqliteStrNDup(pDbToken->z, pDbToken->n);
+ sqliteDequote(zDb);
+ }else{
+ zDb = 0;
+ }
+ if( pTableToken && pTableToken->z ){
+ zTab = sqliteStrNDup(pTableToken->z, pTableToken->n);
+ sqliteDequote(zTab);
+ }else{
+ assert( zDb==0 );
+ zTab = 0;
+ }
+ zCol = sqliteStrNDup(pColumnToken->z, pColumnToken->n);
+ sqliteDequote(zCol);
+ if( sqlite_malloc_failed ){
+ return 1; /* Leak memory (zDb and zTab) if malloc fails */
+ }
+ assert( zTab==0 || pEList==0 );
+
+ pExpr->iTable = -1;
+ for(i=0; i<pSrcList->nSrc; i++){
+ struct SrcList_item *pItem = &pSrcList->a[i];
+ Table *pTab = pItem->pTab;
+ Column *pCol;
+
+ if( pTab==0 ) continue;
+ assert( pTab->nCol>0 );
+ if( zTab ){
+ if( pItem->zAlias ){
+ char *zTabName = pItem->zAlias;
+ if( sqliteStrICmp(zTabName, zTab)!=0 ) continue;
+ }else{
+ char *zTabName = pTab->zName;
+ if( zTabName==0 || sqliteStrICmp(zTabName, zTab)!=0 ) continue;
+ if( zDb!=0 && sqliteStrICmp(db->aDb[pTab->iDb].zName, zDb)!=0 ){
+ continue;
+ }
+ }
+ }
+ if( 0==(cntTab++) ){
+ pExpr->iTable = pItem->iCursor;
+ pExpr->iDb = pTab->iDb;
+ }
+ for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
+ if( sqliteStrICmp(pCol->zName, zCol)==0 ){
+ cnt++;
+ pExpr->iTable = pItem->iCursor;
+ pExpr->iDb = pTab->iDb;
+ /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
+ pExpr->iColumn = j==pTab->iPKey ? -1 : j;
+ pExpr->dataType = pCol->sortOrder & SQLITE_SO_TYPEMASK;
+ break;
+ }
+ }
+ }
+
+ /* 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;
+ if( pTriggerStack->newIdx != -1 && sqliteStrICmp("new", zTab) == 0 ){
+ pExpr->iTable = pTriggerStack->newIdx;
+ assert( pTriggerStack->pTab );
+ pTab = pTriggerStack->pTab;
+ }else if( pTriggerStack->oldIdx != -1 && sqliteStrICmp("old", zTab) == 0 ){
+ pExpr->iTable = pTriggerStack->oldIdx;
+ assert( pTriggerStack->pTab );
+ pTab = pTriggerStack->pTab;
+ }
+
+ if( pTab ){
+ int j;
+ Column *pCol = pTab->aCol;
+
+ pExpr->iDb = pTab->iDb;
+ cntTab++;
+ for(j=0; j < pTab->nCol; j++, pCol++) {
+ if( sqliteStrICmp(pCol->zName, zCol)==0 ){
+ cnt++;
+ pExpr->iColumn = j==pTab->iPKey ? -1 : j;
+ pExpr->dataType = pCol->sortOrder & SQLITE_SO_TYPEMASK;
+ break;
+ }
+ }
+ }
+ }
+
+ /*
+ ** Perhaps the name is a reference to the ROWID
+ */
+ if( cnt==0 && cntTab==1 && sqliteIsRowid(zCol) ){
+ cnt = 1;
+ pExpr->iColumn = -1;
+ pExpr->dataType = SQLITE_SO_NUM;
+ }
+
+ /*
+ ** 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!=0 ){
+ for(j=0; j<pEList->nExpr; j++){
+ char *zAs = pEList->a[j].zName;
+ if( zAs!=0 && sqliteStrICmp(zAs, zCol)==0 ){
+ assert( pExpr->pLeft==0 && pExpr->pRight==0 );
+ pExpr->op = TK_AS;
+ pExpr->iColumn = j;
+ pExpr->pLeft = sqliteExprDup(pEList->a[j].pExpr);
+ sqliteFree(zCol);
+ assert( zTab==0 && zDb==0 );
+ return 0;
+ }
+ }
+ }
+
+ /*
+ ** 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.
+ */
+ if( cnt==0 && zTab==0 && pColumnToken->z[0]=='"' ){
+ sqliteFree(zCol);
+ 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 ){
+ char *z = 0;
+ char *zErr;
+ zErr = cnt==0 ? "no such column: %s" : "ambiguous column name: %s";
+ if( zDb ){
+ sqliteSetString(&z, zDb, ".", zTab, ".", zCol, 0);
+ }else if( zTab ){
+ sqliteSetString(&z, zTab, ".", zCol, 0);
+ }else{
+ z = sqliteStrDup(zCol);
+ }
+ sqliteErrorMsg(pParse, zErr, z);
+ sqliteFree(z);
+ }
+
+ /* Clean up and return
+ */
+ sqliteFree(zDb);
+ sqliteFree(zTab);
+ sqliteFree(zCol);
+ sqliteExprDelete(pExpr->pLeft);
+ pExpr->pLeft = 0;
+ sqliteExprDelete(pExpr->pRight);
+ pExpr->pRight = 0;
+ pExpr->op = TK_COLUMN;
+ sqliteAuthRead(pParse, pExpr, pSrcList);
+ return cnt!=1;
+}
+
/*
** This routine walks an expression tree and resolves references to
** table columns. Nodes of the form ID.ID or ID resolve into an
*/
int sqliteExprResolveIds(
Parse *pParse, /* The parser context */
- SrcList *pTabList, /* List of tables used to resolve column names */
+ SrcList *pSrcList, /* List of tables used to resolve column names */
ExprList *pEList, /* List of expressions used to resolve "AS" */
Expr *pExpr /* The expression to be analyzed. */
){
int i;
- if( pExpr==0 || pTabList==0 ) return 0;
- for(i=0; i<pTabList->nSrc; i++){
- assert( p
TabList->a[i].iCursor>=0 && pTabList->a[i].iCursor<pParse->nTab );
+ if( pExpr==0 || pSrcList==0 ) return 0;
+ for(i=0; i<pSrcList->nSrc; i++){
+ assert( p
SrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab );
}
switch( pExpr->op ){
/* Double-quoted strings (ex: "abc") are used as identifiers if
if( pExpr->token.z[0]=='\'' ) break;
/* Fall thru into the TK_ID case if this is a double-quoted string */
}
- /* A lone identifier. Try and match it as follows:
- **
- ** 1. To the name of a column of one of the tables in pTabList
- **
- ** 2. To the right side of an AS keyword in the column list of
- ** a SELECT statement. (For example, match against 'x' in
- ** "SELECT a+b AS 'x' FROM t1".)
- **
- ** 3. One of the special names "ROWID", "OID", or "_ROWID_".
+ /* A lone identifier is the name of a columnd.
*/
case TK_ID: {
- int cnt = 0; /* Number of matches */
- char *z;
- int iDb = -1;
-
- assert( pExpr->token.z );
- z = sqliteStrNDup(pExpr->token.z, pExpr->token.n);
- sqliteDequote(z);
- if( z==0 ) return 1;
- for(i=0; i<pTabList->nSrc; i++){
- int j;
- Table *pTab = pTabList->a[i].pTab;
- if( pTab==0 ) continue;
- iDb = pTab->iDb;
- assert( pTab->nCol>0 );
- for(j=0; j<pTab->nCol; j++){
- if( sqliteStrICmp(pTab->aCol[j].zName, z)==0 ){
- cnt++;
- pExpr->iTable = pTabList->a[i].iCursor;
- pExpr->iDb = pTab->iDb;
- if( j==pTab->iPKey ){
- /* Substitute the record number for the INTEGER PRIMARY KEY */
- pExpr->iColumn = -1;
- pExpr->dataType = SQLITE_SO_NUM;
- }else{
- pExpr->iColumn = j;
- pExpr->dataType = pTab->aCol[j].sortOrder & SQLITE_SO_TYPEMASK;
- }
- pExpr->op = TK_COLUMN;
- }
- }
- }
- if( cnt==0 && pEList!=0 ){
- int j;
- for(j=0; j<pEList->nExpr; j++){
- char *zAs = pEList->a[j].zName;
- if( zAs!=0 && sqliteStrICmp(zAs, z)==0 ){
- cnt++;
- assert( pExpr->pLeft==0 && pExpr->pRight==0 );
- pExpr->op = TK_AS;
- pExpr->iColumn = j;
- pExpr->pLeft = sqliteExprDup(pEList->a[j].pExpr);
- }
- }
- }
- if( cnt==0 && iDb>=0 && sqliteIsRowid(z) ){
- pExpr->iColumn = -1;
- pExpr->iTable = pTabList->a[0].iCursor;
- pExpr->iDb = iDb;
- cnt = 1 + (pTabList->nSrc>1);
- pExpr->op = TK_COLUMN;
- pExpr->dataType = SQLITE_SO_NUM;
- }
- sqliteFree(z);
- if( cnt==0 && pExpr->token.z[0]!='"' ){
- sqliteErrorMsg(pParse, "no such column: %T", &pExpr->token);
- return 1;
- }else if( cnt>1 ){
- sqliteErrorMsg(pParse, "ambiguous column name: %T", &pExpr->token);
+ if( lookupName(pParse, 0, 0, &pExpr->token, pSrcList, pEList, pExpr) ){
return 1;
}
- if( pExpr->op==TK_COLUMN ){
- sqliteAuthRead(pParse, pExpr, pTabList);
- }
break;
}
** Or a database, table and column: ID.ID.ID
*/
case TK_DOT: {
- int cnt = 0; /* Number of matches */
- int cntTab = 0; /* Number of matching tables */
- int i; /* Loop counter */
- Expr *pLeft, *pRight; /* Left and right subbranches of the expr */
- char *zLeft, *zRight; /* Text of an identifier */
- char *zDb; /* Name of database holding table */
- sqlite *db = pParse->db;
+ Token *pColumn;
+ Token *pTable;
+ Token *pDb;
+ Expr *pRight;
pRight = pExpr->pRight;
if( pRight->op==TK_ID ){
- pLeft = pExpr->pLeft;
- zDb = 0;
+ pDb = 0;
+ pTable = &pExpr->pLeft->token;
+ pColumn = &pRight->token;
}else{
- Expr *pDb = pExpr->pLeft;
- assert( pDb && pDb->op==TK_ID && pDb->token.z );
- zDb = sqliteStrNDup(pDb->token.z, pDb->token.n);
- pLeft = pRight->pLeft;
- pRight = pRight->pRight;
+ assert( pRight->op==TK_DOT );
+ pDb = &pExpr->pLeft->token;
+ pTable = &pRight->pLeft->token;
+ pColumn = &pRight->pRight->token;
}
- assert( pLeft && pLeft->op==TK_ID && pLeft->token.z );
- assert( pRight && pRight->op==TK_ID && pRight->token.z );
- zLeft = sqliteStrNDup(pLeft->token.z, pLeft->token.n);
- zRight = sqliteStrNDup(pRight->token.z, pRight->token.n);
- if( zLeft==0 || zRight==0 ){
- sqliteFree(zLeft);
- sqliteFree(zRight);
- sqliteFree(zDb);
- return 1;
- }
- sqliteDequote(zDb);
- sqliteDequote(zLeft);
- sqliteDequote(zRight);
- pExpr->iTable = -1;
- for(i=0; i<pTabList->nSrc; i++){
- int j;
- char *zTab;
- Table *pTab = pTabList->a[i].pTab;
- if( pTab==0 ) continue;
- assert( pTab->nCol>0 );
- if( pTabList->a[i].zAlias ){
- zTab = pTabList->a[i].zAlias;
- if( sqliteStrICmp(zTab, zLeft)!=0 ) continue;
- }else{
- zTab = pTab->zName;
- if( zTab==0 || sqliteStrICmp(zTab, zLeft)!=0 ) continue;
- if( zDb!=0 && sqliteStrICmp(db->aDb[pTab->iDb].zName, zDb)!=0 ){
- continue;
- }
- }
- if( 0==(cntTab++) ){
- pExpr->iTable = pTabList->a[i].iCursor;
- pExpr->iDb = pTab->iDb;
- }
- for(j=0; j<pTab->nCol; j++){
- if( sqliteStrICmp(pTab->aCol[j].zName, zRight)==0 ){
- cnt++;
- pExpr->iTable = pTabList->a[i].iCursor;
- pExpr->iDb = pTab->iDb;
- /* Substitute the rowid (column -1) for the INTEGER PRIMARY KEY */
- pExpr->iColumn = j==pTab->iPKey ? -1 : j;
- pExpr->dataType = pTab->aCol[j].sortOrder & SQLITE_SO_TYPEMASK;
- }
- }
- }
-
- /* If we have not already resolved this *.* expression, then maybe
- * it is a new.* or old.* trigger argument reference */
- if( cnt == 0 && pParse->trigStack != 0 ){
- TriggerStack *pTriggerStack = pParse->trigStack;
- int t = 0;
- if( pTriggerStack->newIdx != -1 && sqliteStrICmp("new", zLeft) == 0 ){
- pExpr->iTable = pTriggerStack->newIdx;
- assert( pTriggerStack->pTab );
- pExpr->iDb = pTriggerStack->pTab->iDb;
- cntTab++;
- t = 1;
- }
- if( pTriggerStack->oldIdx != -1 && sqliteStrICmp("old", zLeft) == 0 ){
- pExpr->iTable = pTriggerStack->oldIdx;
- assert( pTriggerStack->pTab );
- pExpr->iDb = pTriggerStack->pTab->iDb;
- cntTab++;
- t = 1;
- }
-
- if( t ){
- int j;
- Table *pTab = pTriggerStack->pTab;
- for(j=0; j < pTab->nCol; j++) {
- if( sqliteStrICmp(pTab->aCol[j].zName, zRight)==0 ){
- cnt++;
- pExpr->iColumn = j==pTab->iPKey ? -1 : j;
- pExpr->dataType = pTab->aCol[j].sortOrder & SQLITE_SO_TYPEMASK;
- }
- }
- }
- }
-
- if( cnt==0 && cntTab==1 && sqliteIsRowid(zRight) ){
- cnt = 1;
- pExpr->iColumn = -1;
- pExpr->dataType = SQLITE_SO_NUM;
- }
- sqliteFree(zDb);
- sqliteFree(zLeft);
- sqliteFree(zRight);
- if( cnt==0 ){
- sqliteErrorMsg(pParse, "no such column: %T.%T",
- &pLeft->token, &pRight->token);
- return 1;
- }else if( cnt>1 ){
- sqliteErrorMsg(pParse, "ambiguous column name: %T.%T",
- &pLeft->token, &pRight->token);
+ if( lookupName(pParse, pDb, pTable, pColumn, pSrcList, 0, pExpr) ){
return 1;
}
- sqliteExprDelete(pExpr->pLeft);
- pExpr->pLeft = 0;
- sqliteExprDelete(pExpr->pRight);
- pExpr->pRight = 0;
- pExpr->op = TK_COLUMN;
- sqliteAuthRead(pParse, pExpr, pTabList);
break;
}
case TK_IN: {
Vdbe *v = sqliteGetVdbe(pParse);
if( v==0 ) return 1;
- if( sqliteExprResolveIds(pParse, pTabList, pEList, pExpr->pLeft) ){
+ if( sqliteExprResolveIds(pParse, pSrcList, pEList, pExpr->pLeft) ){
return 1;
}
if( pExpr->pSelect ){
/* For all else, just recursively walk the tree */
default: {
if( pExpr->pLeft
- && sqliteExprResolveIds(pParse, pTabList, pEList, pExpr->pLeft) ){
+ && sqliteExprResolveIds(pParse, pSrcList, pEList, pExpr->pLeft) ){
return 1;
}
if( pExpr->pRight
- && sqliteExprResolveIds(pParse, pTabList, pEList, pExpr->pRight) ){
+ && sqliteExprResolveIds(pParse, pSrcList, pEList, pExpr->pRight) ){
return 1;
}
if( pExpr->pList ){
ExprList *pList = pExpr->pList;
for(i=0; i<pList->nExpr; i++){
Expr *pArg = pList->a[i].pExpr;
- if( sqliteExprResolveIds(pParse, pTabList, pEList, pArg) ){
+ if( sqliteExprResolveIds(pParse, pSrcList, pEList, pArg) ){
return 1;
}
}
projects / thirdparty / sqlite.git / commitdiff
