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Carry column aliases from the parser frontend. Enables queries like
SELECT a FROM t1 tx (a); Allow join syntax, including queries like SELECT * FROM t1 NATURAL JOIN t2; Update RTE structure to hold column aliases in an Attr structure.
This commit is contained in:
Thomas G. Lockhart
@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/parser/parse_relation.c,v 1.34 2000/01/26 05:56:42 momjian Exp $
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* $Header: /cvsroot/pgsql/src/backend/parser/parse_relation.c,v 1.35 2000/02/15 03:37:47 thomas Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -65,6 +65,39 @@ static char *attnum_type[SPECIALS] = {
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"cid",
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};
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/* refnameRangeTableEntries()
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* Given refname, return a list of range table entries
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* This is possible with JOIN syntax, where tables in a join
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* acquire the same reference name
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* - thomas 2000-01-20
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*/
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List *
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refnameRangeTableEntries(ParseState *pstate, char *refname);
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List *
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refnameRangeTableEntries(ParseState *pstate, char *refname)
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{
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List *rteList = NULL;
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List *temp;
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while (pstate != NULL)
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{
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foreach(temp, pstate->p_rtable)
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{
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RangeTblEntry *rte = lfirst(temp);
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if (strcmp(rte->ref->relname, refname) == 0)
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rteList = lappend(rteList, rte);
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}
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/* only allow correlated columns in WHERE clause */
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if (pstate->p_in_where_clause)
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pstate = pstate->parentParseState;
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else
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break;
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}
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return rteList;
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}
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/* given refname, return a pointer to the range table entry */
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RangeTblEntry *
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refnameRangeTableEntry(ParseState *pstate, char *refname)
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@ -77,7 +110,11 @@ refnameRangeTableEntry(ParseState *pstate, char *refname)
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{
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RangeTblEntry *rte = lfirst(temp);
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#ifndef DISABLE_JOIN_SYNTAX
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if (strcmp(rte->ref->relname, refname) == 0)
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#else
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if (!strcmp(rte->refname, refname))
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#endif
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return rte;
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}
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/* only allow correlated columns in WHERE clause */
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@ -106,7 +143,11 @@ refnameRangeTablePosn(ParseState *pstate, char *refname, int *sublevels_up)
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{
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RangeTblEntry *rte = lfirst(temp);
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#ifndef DISABLE_JOIN_SYNTAX
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if (strcmp(rte->ref->relname, refname) == 0)
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#else
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if (!strcmp(rte->refname, refname))
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#endif
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return index;
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index++;
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}
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@ -143,24 +184,52 @@ colnameRangeTableEntry(ParseState *pstate, char *colname)
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foreach(et, rtable)
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{
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RangeTblEntry *rte_candidate = NULL;
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RangeTblEntry *rte = lfirst(et);
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/* only consider RTEs mentioned in FROM or UPDATE/DELETE */
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if (!rte->inFromCl && rte != pstate->p_target_rangetblentry)
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continue;
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if (get_attnum(rte->relid, colname) != InvalidAttrNumber)
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if (rte->ref->attrs != NULL)
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{
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if (rte_result != NULL)
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List *c;
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foreach (c, rte->ref->attrs)
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{
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if (!pstate->p_is_insert ||
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rte != pstate->p_target_rangetblentry)
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elog(ERROR, "Column '%s' is ambiguous", colname);
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if (strcmp(strVal(lfirst(c)), colname) == 0)
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{
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if (rte_candidate != NULL)
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elog(ERROR, "Column '%s' is ambiguous"
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" (internal error)", colname);
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rte_candidate = rte;
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}
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}
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else
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rte_result = rte;
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}
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/* Even if we have an attribute list in the RTE,
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* look for the column here anyway. This is the only
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* way we will find implicit columns like "oid".
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* - thomas 2000-02-07
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*/
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if ((rte_candidate == NULL)
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&& (get_attnum(rte->relid, colname) != InvalidAttrNumber))
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{
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rte_candidate = rte;
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}
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if (rte_candidate == NULL)
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continue;
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if (rte_result != NULL)
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{
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if (!pstate->p_is_insert ||
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rte != pstate->p_target_rangetblentry)
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elog(ERROR, "Column '%s' is ambiguous", colname);
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}
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else
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rte_result = rte;
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}
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/* only allow correlated columns in WHERE clause */
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if (pstate->p_in_where_clause && rte_result == NULL)
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pstate = pstate->parentParseState;
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@ -177,45 +246,65 @@ colnameRangeTableEntry(ParseState *pstate, char *colname)
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RangeTblEntry *
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addRangeTableEntry(ParseState *pstate,
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char *relname,
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char *refname,
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Attr *ref,
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bool inh,
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bool inFromCl,
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bool inJoinSet)
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{
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Relation relation;
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RangeTblEntry *rte;
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int sublevels_up;
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Relation rel;
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RangeTblEntry *rte;
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int maxattrs;
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int sublevels_up;
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int varattno;
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/* Look for an existing rte, if available... */
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if (pstate != NULL)
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{
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int rt_index = refnameRangeTablePosn(pstate, refname,
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&sublevels_up);
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int rt_index = refnameRangeTablePosn(pstate, ref->relname,
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&sublevels_up);
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if (rt_index != 0 && (!inFromCl || sublevels_up == 0))
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{
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if (!strcmp(refname, "*CURRENT*") || !strcmp(refname, "*NEW*"))
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if (!strcmp(ref->relname, "*CURRENT*") || !strcmp(ref->relname, "*NEW*"))
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return (RangeTblEntry *) nth(rt_index - 1, pstate->p_rtable);
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elog(ERROR, "Table name '%s' specified more than once", refname);
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elog(ERROR, "Table name '%s' specified more than once", ref->relname);
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}
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}
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rte = makeNode(RangeTblEntry);
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rte->relname = pstrdup(relname);
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rte->refname = pstrdup(refname);
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rte->relname = relname;
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rte->ref = ref;
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/* Get the rel's OID. This access also ensures that we have an
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* up-to-date relcache entry for the rel. We don't need to keep
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* it open, however.
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* Since this is open anyway, let's check that the number of column
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* aliases is reasonable.
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* - Thomas 2000-02-04
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*/
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relation = heap_openr(relname, AccessShareLock);
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rte->relid = RelationGetRelid(relation);
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heap_close(relation, AccessShareLock);
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rel = heap_openr(relname, AccessShareLock);
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rte->relid = RelationGetRelid(rel);
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maxattrs = RelationGetNumberOfAttributes(rel);
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if (maxattrs < length(ref->attrs))
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elog(ERROR, "Table '%s' has %d columns available but %d columns specified",
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relname, maxattrs, length(ref->attrs));
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/* fill in any unspecified alias columns */
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for (varattno = length(ref->attrs); varattno < maxattrs; varattno++)
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{
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char *attrname;
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attrname = pstrdup(NameStr(rel->rd_att->attrs[varattno]->attname));
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ref->attrs = lappend(ref->attrs, makeString(attrname));
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}
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heap_close(rel, AccessShareLock);
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/*
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* Flags: this RTE should be expanded to include descendant tables,
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* this RTE is in the FROM clause, this RTE should be included in
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* the planner's final join.
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* Flags:
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* - this RTE should be expanded to include descendant tables,
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* - this RTE is in the FROM clause,
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* - this RTE should be included in the planner's final join.
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*/
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rte->inh = inh;
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rte->inFromCl = inFromCl;
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@ -231,23 +320,71 @@ addRangeTableEntry(ParseState *pstate,
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return rte;
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}
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/* expandTable()
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* Populates an Attr with table name and column names
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* This is similar to expandAll(), but does not create an RTE
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* if it does not already exist.
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* - thomas 2000-01-19
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*/
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Attr *
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expandTable(ParseState *pstate, char *refname, bool getaliases)
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{
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Attr *attr;
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RangeTblEntry *rte;
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Relation rel;
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int varattno,
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maxattrs;
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rte = refnameRangeTableEntry(pstate, refname);
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if (getaliases && (rte != NULL) && (rte->ref != NULL)
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&& (length(rte->ref->attrs) > 0))
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{
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return rte->ref;
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}
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if (rte != NULL)
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rel = heap_open(rte->relid, AccessShareLock);
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else
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rel = heap_openr(refname, AccessShareLock);
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if (rel == NULL)
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elog(ERROR, "Relation '%s' not found", refname);
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maxattrs = RelationGetNumberOfAttributes(rel);
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attr = makeAttr(refname, NULL);
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for (varattno = 0; varattno < maxattrs; varattno++)
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{
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char *attrname;
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attrname = pstrdup(NameStr(rel->rd_att->attrs[varattno]->attname));
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attr->attrs = lappend(attr->attrs, makeString(attrname));
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}
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heap_close(rel, AccessShareLock);
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return attr;
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}
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/*
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* expandAll -
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* makes a list of attributes
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*/
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List *
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expandAll(ParseState *pstate, char *relname, char *refname, int *this_resno)
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expandAll(ParseState *pstate, char *relname, Attr *ref, int *this_resno)
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{
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List *te_list = NIL;
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RangeTblEntry *rte;
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Relation rel;
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int varattno,
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maxattrs;
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List *te_list = NIL;
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RangeTblEntry *rte;
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Relation rel;
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int varattno,
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maxattrs;
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rte = refnameRangeTableEntry(pstate, refname);
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rte = refnameRangeTableEntry(pstate, ref->relname);
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if (rte == NULL)
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{
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rte = addRangeTableEntry(pstate, relname, refname,
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rte = addRangeTableEntry(pstate, relname, ref,
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FALSE, FALSE, TRUE);
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#ifdef WARN_FROM
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elog(NOTICE,"Adding missing FROM-clause entry%s for table %s",
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@ -262,12 +399,19 @@ expandAll(ParseState *pstate, char *relname, char *refname, int *this_resno)
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for (varattno = 0; varattno < maxattrs; varattno++)
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{
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char *attrname;
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Var *varnode;
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TargetEntry *te = makeNode(TargetEntry);
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char *attrname;
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char *label;
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Var *varnode;
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TargetEntry *te = makeNode(TargetEntry);
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attrname = pstrdup(NameStr(rel->rd_att->attrs[varattno]->attname));
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varnode = make_var(pstate, rte->relid, refname, attrname);
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/* varattno is zero-based, so check that length() is always greater */
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if (length(rte->ref->attrs) > varattno)
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label = pstrdup(strVal(nth(varattno, rte->ref->attrs)));
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else
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label = attrname;
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varnode = make_var(pstate, rte->relid, relname, attrname);
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/*
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* Even if the elements making up a set are complex, the set
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@ -277,7 +421,7 @@ expandAll(ParseState *pstate, char *relname, char *refname, int *this_resno)
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te->resdom = makeResdom((AttrNumber) (*this_resno)++,
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varnode->vartype,
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varnode->vartypmod,
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attrname,
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label,
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(Index) 0,
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(Oid) 0,
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false);
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@ -306,16 +450,32 @@ attnameAttNum(Relation rd, char *a)
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if (!namestrcmp(&(rd->rd_att->attrs[i]->attname), a))
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return i + 1;
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for (i = 0; i < SPECIALS; i++)
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if (!strcmp(special_attr[i].field, a))
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return special_attr[i].code;
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if ((i = specialAttNum(a)) != InvalidAttrNumber)
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return i;
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/* on failure */
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elog(ERROR, "Relation '%s' does not have attribute '%s'",
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RelationGetRelationName(rd), a);
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return 0; /* lint */
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return InvalidAttrNumber; /* lint */
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}
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/* specialAttNum()
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* Check attribute name to see if it is "special", e.g. "oid".
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* - thomas 2000-02-07
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*/
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int
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specialAttNum(char *a)
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{
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int i;
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for (i = 0; i < SPECIALS; i++)
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if (!strcmp(special_attr[i].field, a))
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return special_attr[i].code;
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return InvalidAttrNumber;
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}
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/*
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* Given range variable, return whether attribute of this name
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* is a set.
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@ -372,3 +532,8 @@ attnumTypeId(Relation rd, int attid)
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*/
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return rd->rd_att->attrs[attid - 1]->atttypid;
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}
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