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Modularize the column name resolution code so that it is smaller, faster,

Browse Source 
and ready for some enhancements that will fix long-standing name
resolutions problems. (CVS 1198)

FossilOrigin-Name: d3648034b409822909d79eb5aa4e64cafa986541
This commit is contained in:
drh 2004-01-25 22:44:58 +00:00
parent b733d03749
commit 8141f61ef2
3 changed files with 245 additions and 200 deletions
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12
manifest
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@ -1,5 +1,5 @@
C Add\sthe\sability\sto\sgroup\sFROM\sterms\susing\sparentheses.\s\sNames\sof\scolumns\sin\na\sjoin\sno\slonger\sinclude\sthe\stable\sname.\s(CVS\s1197)
D 2004-01-24T20:18:13
C Modularize\sthe\scolumn\sname\sresolution\scode\sso\sthat\sit\sis\ssmaller,\sfaster,\nand\sready\sfor\ssome\senhancements\sthat\swill\sfix\slong-standing\sname\nresolutions\sproblems.\s(CVS\s1198)
D 2004-01-25T22:44:59
F Makefile.in 0515ff9218ad8d5a8f6220f0494b8ef94c67013b
F Makefile.linux-gcc b86a99c493a5bfb402d1d9178dcdc4bd4b32f906
F README f1de682fbbd94899d50aca13d387d1b3fd3be2dd
@ -31,7 +31,7 @@ F src/copy.c 9e47975ea96751c658bcf1a0c4f0bb7c6ee61e73
F src/date.c c6b7e3fa5364d50fe19641882194f3c75364a5af
F src/delete.c 0778fe05df0a1d62ac27fd1a3dba237c186ff4d1
F src/encode.c 9e70ea1e4e746f23f18180949e94f1bb1c2220d3
F src/expr.c e6a05bec1ca8d80d0901e5ff59c4ce3d9553f6cc
F src/expr.c 3928893e8a7576484cd2ed5548468ba978d8005a
F src/func.c fd710743e4026dfebfd48c12d20b1a5c27318fa5
F src/hash.c 9b56ef3b291e25168f630d5643a4264ec011c70e
F src/hash.h 3247573ab95b9dd90bcca0307a75d9a16da1ccc7
@ -181,7 +181,7 @@ F www/speed.tcl 2f6b1155b99d39adb185f900456d1d592c4832b3
F www/sqlite.tcl 3c83b08cf9f18aa2d69453ff441a36c40e431604
F www/tclsqlite.tcl b9271d44dcf147a93c98f8ecf28c927307abd6da
F www/vdbe.tcl 9b9095d4495f37697fd1935d10e14c6015e80aa1
P 3dc951951947a9188ecba1b84e48c65e34c4df16
R c11f9dd26aca5e351dec881862f5d549
P 3626f6d4a1adb4209d5bd9e6477343b52bddbdf2
R dd7edf82e94deb20012095d659a5fe16
U drh
Z 2a2e36c650f4fa8bf25792ffa5a54e26
Z cf295a8614ac26ab40dca8b761e6d91c

2
manifest.uuid
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@ -1 +1 @@
3626f6d4a1adb4209d5bd9e6477343b52bddbdf2
d3648034b409822909d79eb5aa4e64cafa986541

431
src/expr.c
View File

@ -12,7 +12,7 @@
** 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>
@ -374,6 +374,221 @@ int sqliteIsRowid(const char *z){
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
@ -407,15 +622,15 @@ int sqliteIsRowid(const char *z){
*/
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( pTabList->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( pSrcList->a[i].iCursor>=0 && pSrcList->a[i].iCursor<pParse->nTab );
}
switch( pExpr->op ){
/* Double-quoted strings (ex: "abc") are used as identifiers if
@ -426,79 +641,11 @@ int sqliteExprResolveIds(
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);
if( lookupName(pParse, 0, 0, &pExpr->token, pSrcList, pEList, pExpr) ){
return 1;
}else if( cnt>1 ){
sqliteErrorMsg(pParse, "ambiguous column name: %T", &pExpr->token);
return 1;
}
if( pExpr->op==TK_COLUMN ){
sqliteAuthRead(pParse, pExpr, pTabList);
}
break;
}
@ -507,134 +654,32 @@ int sqliteExprResolveIds(
** 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);
if( lookupName(pParse, pDb, pTable, pColumn, pSrcList, 0, pExpr) ){
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);
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 ){
@ -704,11 +749,11 @@ int sqliteExprResolveIds(
/* 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 ){
@ -716,7 +761,7 @@ int sqliteExprResolveIds(
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;
}
}