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Improve error messages for missing-FROM-entry cases, as per recent discussion.

This commit is contained in:
Tom Lane 2006-01-10 21:59:59 +00:00
parent 8ea91ba18e
commit 399437acec
2 changed files with 98 additions and 18 deletions
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114
src/backend/parser/parse_relation.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.117 2005/11/22 18:17:16 momjian Exp $
* $PostgreSQL: pgsql/src/backend/parser/parse_relation.c,v 1.118 2006/01/10 21:59:59 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -161,7 +161,7 @@ scanNameSpaceForRelid(ParseState *pstate, Oid relid)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
/* yes, the test for alias==NULL should be there... */
/* yes, the test for alias == NULL should be there... */
if (rte->rtekind == RTE_RELATION &&
rte->relid == relid &&
rte->alias == NULL)
@ -177,6 +177,48 @@ scanNameSpaceForRelid(ParseState *pstate, Oid relid)
return result;
}
/*
* searchRangeTable
* See if any RangeTblEntry could possibly match the RangeVar.
* If so, return a pointer to the RangeTblEntry; else return NULL.
*
* This is different from refnameRangeTblEntry in that it considers every
* entry in the ParseState's rangetable(s), not only those that are currently
* visible in the p_relnamespace lists. This behavior is invalid per the SQL
* spec, and it may give ambiguous results (there might be multiple equally
* valid matches, but only one will be returned). This must be used ONLY
* as a heuristic in giving suitable error messages. See warnAutoRange.
*
* Notice that we consider both matches on actual relation name and matches
* on alias.
*/
static RangeTblEntry *
searchRangeTable(ParseState *pstate, RangeVar *relation)
{
Oid relId = RangeVarGetRelid(relation, true);
char *refname = relation->relname;
while (pstate != NULL)
{
ListCell *l;
foreach(l, pstate->p_rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
if (OidIsValid(relId) &&
rte->rtekind == RTE_RELATION &&
rte->relid == relId)
return rte;
if (strcmp(rte->eref->aliasname, refname) == 0)
return rte;
}
pstate = pstate->parentParseState;
}
return NULL;
}
/*
* Check for relation-name conflicts between two relnamespace lists.
* Raise an error if any is found.
@ -1005,6 +1047,8 @@ addImplicitRTE(ParseState *pstate, RangeVar *relation)
{
RangeTblEntry *rte;
/* issue warning or error as needed */
warnAutoRange(pstate, relation);
/*
* Note that we set inFromCl true, so that the RTE will be listed
* explicitly if the parsetree is ever decompiled by ruleutils.c. This
@ -1014,7 +1058,6 @@ addImplicitRTE(ParseState *pstate, RangeVar *relation)
rte = addRangeTableEntry(pstate, relation, NULL, false, true);
/* Add to joinlist and relnamespace, but not varnamespace */
addRTEtoQuery(pstate, rte, true, true, false);
warnAutoRange(pstate, relation);
return rte;
}
@ -1761,31 +1804,68 @@ attnumTypeId(Relation rd, int attid)
static void
warnAutoRange(ParseState *pstate, RangeVar *relation)
{
RangeTblEntry *rte;
int sublevels_up;
const char *badAlias = NULL;
/*
* Check to see if there are any potential matches in the query's
* rangetable. This affects the message we provide.
*/
rte = searchRangeTable(pstate, relation);
/*
* If we found a match that has an alias and the alias is visible in
* the namespace, then the problem is probably use of the relation's
* real name instead of its alias, ie "SELECT foo.* FROM foo f".
* This mistake is common enough to justify a specific hint.
*
* If we found a match that doesn't meet those criteria, assume the
* problem is illegal use of a relation outside its scope, as in the
* MySQL-ism "SELECT ... FROM a, b LEFT JOIN c ON (a.x = c.y)".
*/
if (rte && rte->alias &&
strcmp(rte->eref->aliasname, relation->relname) != 0 &&
refnameRangeTblEntry(pstate, NULL, rte->eref->aliasname,
&sublevels_up) == rte)
badAlias = rte->eref->aliasname;
if (!add_missing_from)
{
if (pstate->parentParseState != NULL)
if (rte)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("missing FROM-clause entry in subquery for table \"%s\"",
relation->relname)));
errmsg("invalid reference to FROM-clause entry for table \"%s\"",
relation->relname),
(badAlias ?
errhint("Perhaps you meant to reference the table alias \"%s\".",
badAlias) :
errhint("There is an entry for table \"%s\", but it cannot be referenced from this part of the query.",
rte->eref->aliasname))));
else
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("missing FROM-clause entry for table \"%s\"",
relation->relname)));
(pstate->parentParseState ?
errmsg("missing FROM-clause entry in subquery for table \"%s\"",
relation->relname) :
errmsg("missing FROM-clause entry for table \"%s\"",
relation->relname))));
}
else
{
/* just issue a warning */
if (pstate->parentParseState != NULL)
ereport(NOTICE,
(errcode(ERRCODE_UNDEFINED_TABLE),
errmsg("adding missing FROM-clause entry in subquery for table \"%s\"",
relation->relname)));
else
ereport(NOTICE,
(errcode(ERRCODE_UNDEFINED_TABLE),
ereport(NOTICE,
(errcode(ERRCODE_UNDEFINED_TABLE),
(pstate->parentParseState ?
errmsg("adding missing FROM-clause entry in subquery for table \"%s\"",
relation->relname) :
errmsg("adding missing FROM-clause entry for table \"%s\"",
relation->relname)));
relation->relname)),
(badAlias ?
errhint("Perhaps you meant to reference the table alias \"%s\".",
badAlias) :
(rte ?
errhint("There is an entry for table \"%s\", but it cannot be referenced from this part of the query.",
rte->eref->aliasname) : 0))));
}
}

2
src/test/regress/expected/rowtypes.out
View File

@ -60,7 +60,7 @@ select * from quadtable;
(2 rows)
select f1, q.c1 from quadtable; -- fails, q is a table reference
ERROR: relation "q" does not exist
ERROR: missing FROM-clause entry for table "q"
select f1, (q).c1, (qq.q).c1.i from quadtable qq;
f1 | c1 | i
----+-----------+-----