parse_relation.c

来自「PostgreSQL7.4.6 for Linux」· C语言 代码 · 共 1,944 行 · 第 1/4 页

					aliasvars = lnext(aliasvars);
				}
				Assert(aliasvars == NIL);
			}
			break;
		default:
			elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
	}
}

/*
 * expandRelAttrs -
 *	  Workhorse for "*" expansion: produce a list of targetentries
 *	  for the attributes of the rte
 */
List *
expandRelAttrs(ParseState *pstate, RangeTblEntry *rte)
{
	List	   *names,
			   *vars;
	List	   *te_list = NIL;

	expandRTE(pstate, rte, &names, &vars);

	while (names)
	{
		char	   *label = strVal(lfirst(names));
		Node	   *varnode = (Node *) lfirst(vars);
		TargetEntry *te = makeNode(TargetEntry);

		te->resdom = makeResdom((AttrNumber) pstate->p_next_resno++,
								exprType(varnode),
								exprTypmod(varnode),
								label,
								false);
		te->expr = (Expr *) varnode;
		te_list = lappend(te_list, te);

		names = lnext(names);
		vars = lnext(vars);
	}

	Assert(vars == NIL);		/* lists not same length? */

	return te_list;
}

/*
 * get_rte_attribute_name
 *		Get an attribute name from a RangeTblEntry
 *
 * This is unlike get_attname() because we use aliases if available.
 * In particular, it will work on an RTE for a subselect or join, whereas
 * get_attname() only works on real relations.
 *
 * "*" is returned if the given attnum is InvalidAttrNumber --- this case
 * occurs when a Var represents a whole tuple of a relation.
 */
char *
get_rte_attribute_name(RangeTblEntry *rte, AttrNumber attnum)
{
	if (attnum == InvalidAttrNumber)
		return "*";

	/*
	 * If there is a user-written column alias, use it.
	 */
	if (rte->alias &&
		attnum > 0 && attnum <= length(rte->alias->colnames))
		return strVal(nth(attnum - 1, rte->alias->colnames));

	/*
	 * If the RTE is a relation, go to the system catalogs not the
	 * eref->colnames list.  This is a little slower but it will give the
	 * right answer if the column has been renamed since the eref list was
	 * built (which can easily happen for rules).
	 */
	if (rte->rtekind == RTE_RELATION)
		return get_relid_attribute_name(rte->relid, attnum);

	/*
	 * Otherwise use the column name from eref.  There should always be
	 * one.
	 */
	if (attnum > 0 && attnum <= length(rte->eref->colnames))
		return strVal(nth(attnum - 1, rte->eref->colnames));

	/* else caller gave us a bogus attnum */
	elog(ERROR, "invalid attnum %d for rangetable entry %s",
		 attnum, rte->eref->aliasname);
	return NULL;				/* keep compiler quiet */
}

/*
 * get_rte_attribute_type
 *		Get attribute type information from a RangeTblEntry
 */
void
get_rte_attribute_type(RangeTblEntry *rte, AttrNumber attnum,
					   Oid *vartype, int32 *vartypmod)
{
	switch (rte->rtekind)
	{
		case RTE_RELATION:
			{
				/* Plain relation RTE --- get the attribute's type info */
				HeapTuple	tp;
				Form_pg_attribute att_tup;

				tp = SearchSysCache(ATTNUM,
									ObjectIdGetDatum(rte->relid),
									Int16GetDatum(attnum),
									0, 0);
				if (!HeapTupleIsValid(tp))		/* shouldn't happen */
					elog(ERROR, "cache lookup failed for attribute %d of relation %u",
						 attnum, rte->relid);
				att_tup = (Form_pg_attribute) GETSTRUCT(tp);

				/*
				 * If dropped column, pretend it ain't there.  See notes
				 * in scanRTEForColumn.
				 */
				if (att_tup->attisdropped)
					ereport(ERROR,
							(errcode(ERRCODE_UNDEFINED_COLUMN),
							 errmsg("column \"%s\" of relation \"%s\" does not exist",
									NameStr(att_tup->attname),
									get_rel_name(rte->relid))));
				*vartype = att_tup->atttypid;
				*vartypmod = att_tup->atttypmod;
				ReleaseSysCache(tp);
			}
			break;
		case RTE_SUBQUERY:
			{
				/* Subselect RTE --- get type info from subselect's tlist */
				TargetEntry *te = get_tle_by_resno(rte->subquery->targetList,
												   attnum);

				if (te == NULL || te->resdom->resjunk)
					elog(ERROR, "subquery %s does not have attribute %d",
						 rte->eref->aliasname, attnum);
				*vartype = te->resdom->restype;
				*vartypmod = te->resdom->restypmod;
			}
			break;
		case RTE_FUNCTION:
			{
				/* Function RTE */
				Oid			funcrettype = exprType(rte->funcexpr);
				char		functyptype = get_typtype(funcrettype);
				List	   *coldeflist = rte->coldeflist;

				if (functyptype == 'c')
				{
					/*
					 * Composite data type, i.e. a table's row type Same
					 * as ordinary relation RTE
					 */
					Oid			funcrelid = typeidTypeRelid(funcrettype);
					HeapTuple	tp;
					Form_pg_attribute att_tup;

					if (!OidIsValid(funcrelid)) /* shouldn't happen */
						elog(ERROR, "invalid typrelid for complex type %u",
							 funcrettype);

					tp = SearchSysCache(ATTNUM,
										ObjectIdGetDatum(funcrelid),
										Int16GetDatum(attnum),
										0, 0);
					if (!HeapTupleIsValid(tp))	/* shouldn't happen */
						elog(ERROR, "cache lookup failed for attribute %d of relation %u",
							 attnum, funcrelid);
					att_tup = (Form_pg_attribute) GETSTRUCT(tp);

					/*
					 * If dropped column, pretend it ain't there.  See
					 * notes in scanRTEForColumn.
					 */
					if (att_tup->attisdropped)
						ereport(ERROR,
								(errcode(ERRCODE_UNDEFINED_COLUMN),
								 errmsg("column \"%s\" of relation \"%s\" does not exist",
										NameStr(att_tup->attname),
										get_rel_name(funcrelid))));
					*vartype = att_tup->atttypid;
					*vartypmod = att_tup->atttypmod;
					ReleaseSysCache(tp);
				}
				else if (functyptype == 'b' || functyptype == 'd')
				{
					/*
					 * Must be a base data type, i.e. scalar
					 */
					*vartype = funcrettype;
					*vartypmod = -1;
				}
				else if (functyptype == 'p' && funcrettype == RECORDOID)
				{
					ColumnDef  *colDef = nth(attnum - 1, coldeflist);

					*vartype = typenameTypeId(colDef->typename);
					*vartypmod = -1;
				}
				else
					ereport(ERROR,
							(errcode(ERRCODE_DATATYPE_MISMATCH),
							 errmsg("function in FROM has unsupported return type")));
			}
			break;
		case RTE_JOIN:
			{
				/*
				 * Join RTE --- get type info from join RTE's alias
				 * variable
				 */
				Node	   *aliasvar;

				Assert(attnum > 0 && attnum <= length(rte->joinaliasvars));
				aliasvar = (Node *) nth(attnum - 1, rte->joinaliasvars);
				*vartype = exprType(aliasvar);
				*vartypmod = exprTypmod(aliasvar);
			}
			break;
		default:
			elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
	}
}

/*
 * get_rte_attribute_is_dropped
 *		Check whether attempted attribute ref is to a dropped column
 */
static bool
get_rte_attribute_is_dropped(RangeTblEntry *rte, AttrNumber attnum)
{
	bool		result;

	switch (rte->rtekind)
	{
		case RTE_RELATION:
			{
				/* Plain relation RTE --- get the attribute's type info */
				HeapTuple	tp;
				Form_pg_attribute att_tup;

				tp = SearchSysCache(ATTNUM,
									ObjectIdGetDatum(rte->relid),
									Int16GetDatum(attnum),
									0, 0);
				if (!HeapTupleIsValid(tp))		/* shouldn't happen */
					elog(ERROR, "cache lookup failed for attribute %d of relation %u",
						 attnum, rte->relid);
				att_tup = (Form_pg_attribute) GETSTRUCT(tp);
				result = att_tup->attisdropped;
				ReleaseSysCache(tp);
			}
			break;
		case RTE_SUBQUERY:
		case RTE_JOIN:
			/* Subselect and join RTEs never have dropped columns */
			result = false;
			break;
		case RTE_FUNCTION:
			{
				/* Function RTE */
				Oid			funcrettype = exprType(rte->funcexpr);
				Oid			funcrelid = typeidTypeRelid(funcrettype);

				if (OidIsValid(funcrelid))
				{
					/*
					 * Composite data type, i.e. a table's row type Same
					 * as ordinary relation RTE
					 */
					HeapTuple	tp;
					Form_pg_attribute att_tup;

					tp = SearchSysCache(ATTNUM,
										ObjectIdGetDatum(funcrelid),
										Int16GetDatum(attnum),
										0, 0);
					if (!HeapTupleIsValid(tp))	/* shouldn't happen */
						elog(ERROR, "cache lookup failed for attribute %d of relation %u",
							 attnum, funcrelid);
					att_tup = (Form_pg_attribute) GETSTRUCT(tp);
					result = att_tup->attisdropped;
					ReleaseSysCache(tp);
				}
				else
				{
					/*
					 * Must be a base data type, i.e. scalar
					 */
					result = false;
				}
			}
			break;
		default:
			elog(ERROR, "unrecognized RTE kind: %d", (int) rte->rtekind);
			result = false;		/* keep compiler quiet */
	}

	return result;
}

/*
 * Given a targetlist and a resno, return the matching TargetEntry
 *
 * Returns NULL if resno is not present in list.
 *
 * Note: we need to search, rather than just indexing with nth(), because
 * not all tlists are sorted by resno.
 */
TargetEntry *
get_tle_by_resno(List *tlist, AttrNumber resno)
{
	List	   *i;

	foreach(i, tlist)
	{
		TargetEntry *tle = (TargetEntry *) lfirst(i);

		if (tle->resdom->resno == resno)
			return tle;
	}
	return NULL;
}

/*
 *	given relation and att name, return id of variable
 *
 *	This should only be used if the relation is already
 *	heap_open()'ed.  Use the cache version get_attnum()
 *	for access to non-opened relations.
 */
int
attnameAttNum(Relation rd, const char *attname, bool sysColOK)
{
	int			i;

	for (i = 0; i < rd->rd_rel->relnatts; i++)
	{
		Form_pg_attribute att = rd->rd_att->attrs[i];

		if (namestrcmp(&(att->attname), attname) == 0 && !att->attisdropped)
			return i + 1;
	}

	if (sysColOK)
	{
		if ((i = specialAttNum(attname)) != InvalidAttrNumber)
		{
			if (i != ObjectIdAttributeNumber || rd->rd_rel->relhasoids)
				return i;
		}
	}

	/* on failure */
	ereport(ERROR,
			(errcode(ERRCODE_UNDEFINED_COLUMN),
			 errmsg("column \"%s\" of relation \"%s\" does not exist",
					attname, RelationGetRelationName(rd))));
	return InvalidAttrNumber;	/* keep compiler quiet */
}

/* specialAttNum()
 *
 * Check attribute name to see if it is "special", e.g. "oid".
 * - thomas 2000-02-07
 *
 * Note: this only discovers whether the name could be a system attribute.
 * Caller needs to verify that it really is an attribute of the rel,
 * at least in the case of "oid", which is now optional.
 */
static int
specialAttNum(const char *attname)
{
	Form_pg_attribute sysatt;

	sysatt = SystemAttributeByName(attname,
								   true /* "oid" will be accepted */ );
	if (sysatt != NULL)
		return sysatt->attnum;
	return InvalidAttrNumber;
}


/*
 * given attribute id, return name of that attribute
 *
 *	This should only be used if the relation is already
 *	heap_open()'ed.  Use the cache version get_atttype()
 *	for access to non-opened relations.
 */
Name
attnumAttName(Relation rd, int attid)
{
	if (attid <= 0)
	{
		Form_pg_attribute sysatt;

		sysatt = SystemAttributeDefinition(attid, rd->rd_rel->relhasoids);
		return &sysatt->attname;
	}
	if (attid > rd->rd_att->natts)
		elog(ERROR, "invalid attribute number %d", attid);
	return &rd->rd_att->attrs[attid - 1]->attname;
}

/*
 * given attribute id, return type of that attribute
 *
 *	This should only be used if the relation is already
 *	heap_open()'ed.  Use the cache version get_atttype()
 *	for access to non-opened relations.
 */
Oid
attnumTypeId(Relation rd, int attid)
{
	if (attid <= 0)
	{
		Form_pg_attribute sysatt;

		sysatt = SystemAttributeDefinition(attid, rd->rd_rel->relhasoids);
		return sysatt->atttypid;
	}
	if (attid > rd->rd_att->natts)
		elog(ERROR, "invalid attribute number %d", attid);
	return rd->rd_att->attrs[attid - 1]->atttypid;
}

/*
 * Generate a warning or error about an implicit RTE, if appropriate.
 *
 * If ADD_MISSING_FROM is not enabled, raise an error.
 *
 * Our current theory on warnings is that we should allow "SELECT foo.*"
 * but warn about a mixture of explicit and implicit RTEs.
 */
static void
warnAutoRange(ParseState *pstate, RangeVar *relation)
{
	bool		foundInFromCl = false;
	List	   *temp;

	if (!add_missing_from)
	{
		if (pstate->parentParseState != NULL)
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_TABLE),
					 errmsg("missing FROM-clause entry in subquery for table \"%s\"",
							relation->relname)));
		else
			ereport(ERROR,
					(errcode(ERRCODE_UNDEFINED_TABLE),
					 errmsg("missing FROM-clause entry for table \"%s\"",
							relation->relname)));
	}

	foreach(temp, pstate->p_rtable)
	{
		RangeTblEntry *rte = lfirst(temp);

		if (rte->inFromCl)
		{
			foundInFromCl = true;
			break;
		}
	}
	if (foundInFromCl)
	{
		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),
			  errmsg("adding missing FROM-clause entry for table \"%s\"",
					 relation->relname)));
	}
}