analyze.c

来自「PostgreSQL7.4.6 for Linux」· C语言 代码 · 共 2,258 行 · 第 1/5 页

				{
					found = true;
					break;
				}
			}
			if (found)
			{
				/* found column in the new table; force it to be NOT NULL */
				if (constraint->contype == CONSTR_PRIMARY)
					column->is_not_null = TRUE;
			}
			else if (SystemAttributeByName(key, cxt->hasoids) != NULL)
			{
				/*
				 * column will be a system column in the new table, so
				 * accept it.  System columns can't ever be null, so no
				 * need to worry about PRIMARY/NOT NULL constraint.
				 */
				found = true;
			}
			else if (cxt->inhRelations)
			{
				/* try inherited tables */
				List	   *inher;

				foreach(inher, cxt->inhRelations)
				{
					RangeVar   *inh = lfirst(inher);
					Relation	rel;
					int			count;

					Assert(IsA(inh, RangeVar));
					rel = heap_openrv(inh, AccessShareLock);
					if (rel->rd_rel->relkind != RELKIND_RELATION)
						ereport(ERROR,
								(errcode(ERRCODE_WRONG_OBJECT_TYPE),
						errmsg("inherited relation \"%s\" is not a table",
							   inh->relname)));
					for (count = 0; count < rel->rd_att->natts; count++)
					{
						Form_pg_attribute inhattr = rel->rd_att->attrs[count];
						char	   *inhname = NameStr(inhattr->attname);

						if (inhattr->attisdropped)
							continue;
						if (strcmp(key, inhname) == 0)
						{
							found = true;

							/*
							 * We currently have no easy way to force an
							 * inherited column to be NOT NULL at
							 * creation, if its parent wasn't so already.
							 * We leave it to DefineIndex to fix things up
							 * in this case.
							 */
							break;
						}
					}
					heap_close(rel, NoLock);
					if (found)
						break;
				}
			}
			else if (OidIsValid(cxt->relOid))
			{
				/* ALTER TABLE case: does column already exist? */
				HeapTuple	atttuple;

				atttuple = SearchSysCacheAttName(cxt->relOid, key);
				if (HeapTupleIsValid(atttuple))
				{
					found = true;

					/*
					 * If it's not already NOT NULL, leave it to
					 * DefineIndex to fix later.
					 */
					ReleaseSysCache(atttuple);
				}
			}

			if (!found)
				ereport(ERROR,
						(errcode(ERRCODE_UNDEFINED_COLUMN),
					  errmsg("column \"%s\" named in key does not exist",
							 key)));

			/* Check for PRIMARY KEY(foo, foo) */
			foreach(columns, index->indexParams)
			{
				iparam = (IndexElem *) lfirst(columns);
				if (iparam->name && strcmp(key, iparam->name) == 0)
				{
					if (index->primary)
						ereport(ERROR,
								(errcode(ERRCODE_DUPLICATE_COLUMN),
								 errmsg("column \"%s\" appears twice in primary key constraint",
										key)));
					else
						ereport(ERROR,
								(errcode(ERRCODE_DUPLICATE_COLUMN),
								 errmsg("column \"%s\" appears twice in unique constraint",
										key)));
				}
			}

			/* OK, add it to the index definition */
			iparam = makeNode(IndexElem);
			iparam->name = pstrdup(key);
			iparam->expr = NULL;
			iparam->opclass = NIL;
			index->indexParams = lappend(index->indexParams, iparam);
		}

		indexlist = lappend(indexlist, index);
	}

	/*
	 * Scan the index list and remove any redundant index specifications.
	 * This can happen if, for instance, the user writes UNIQUE PRIMARY
	 * KEY. A strict reading of SQL92 would suggest raising an error
	 * instead, but that strikes me as too anal-retentive. - tgl
	 * 2001-02-14
	 *
	 * XXX in ALTER TABLE case, it'd be nice to look for duplicate
	 * pre-existing indexes, too.
	 */
	cxt->alist = NIL;
	if (cxt->pkey != NULL)
	{
		/* Make sure we keep the PKEY index in preference to others... */
		cxt->alist = makeList1(cxt->pkey);
	}
	while (indexlist != NIL)
	{
		index = lfirst(indexlist);

		/* if it's pkey, it's already in cxt->alist */
		if (index != cxt->pkey)
		{
			bool		keep = true;
			List	   *priorlist;

			foreach(priorlist, cxt->alist)
			{
				IndexStmt  *priorindex = lfirst(priorlist);

				if (equal(index->indexParams, priorindex->indexParams))
				{
					/*
					 * If the prior index is as yet unnamed, and this one
					 * is named, then transfer the name to the prior
					 * index. This ensures that if we have named and
					 * unnamed constraints, we'll use (at least one of)
					 * the names for the index.
					 */
					if (priorindex->idxname == NULL)
						priorindex->idxname = index->idxname;
					keep = false;
					break;
				}
			}

			if (keep)
				cxt->alist = lappend(cxt->alist, index);
		}

		indexlist = lnext(indexlist);
	}

	/*
	 * Finally, select unique names for all not-previously-named indices,
	 * and display NOTICE messages.
	 *
	 * XXX in ALTER TABLE case, we fail to consider name collisions against
	 * pre-existing indexes.
	 */
	foreach(indexlist, cxt->alist)
	{
		index = lfirst(indexlist);

		if (index->idxname == NULL && index->indexParams != NIL)
		{
			iparam = (IndexElem *) lfirst(index->indexParams);
			/* we should never see an expression item here */
			Assert(iparam->expr == NULL);
			index->idxname = CreateIndexName(cxt->relation->relname,
											 iparam->name,
											 "key",
											 cxt->alist);
		}
		if (index->idxname == NULL)		/* should not happen */
			elog(ERROR, "failed to make implicit index name");

		ereport(NOTICE,
				(errmsg("%s / %s%s will create implicit index \"%s\" for table \"%s\"",
						cxt->stmtType,
			   (strcmp(cxt->stmtType, "ALTER TABLE") == 0) ? "ADD " : "",
						(index->primary ? "PRIMARY KEY" : "UNIQUE"),
						index->idxname, cxt->relation->relname)));
	}
}

static void
transformFKConstraints(ParseState *pstate, CreateStmtContext *cxt,
					   bool isAddConstraint)
{
	if (cxt->fkconstraints == NIL)
		return;

	/*
	 * For ALTER TABLE ADD CONSTRAINT, nothing to do.  For CREATE TABLE or
	 * ALTER TABLE ADD COLUMN, gin up an ALTER TABLE ADD CONSTRAINT
	 * command to execute after the basic command is complete.
	 *
	 * Note: the ADD CONSTRAINT command must also execute after any index
	 * creation commands.  Thus, this should run after
	 * transformIndexConstraints, so that the CREATE INDEX commands are
	 * already in cxt->alist.
	 */
	if (!isAddConstraint)
	{
		AlterTableStmt *alterstmt = makeNode(AlterTableStmt);
		List	   *fkclist;

		alterstmt->subtype = 'c';		/* preprocessed add constraint */
		alterstmt->relation = cxt->relation;
		alterstmt->name = NULL;
		alterstmt->def = (Node *) cxt->fkconstraints;

		/* Don't need to scan the table contents in this case */
		foreach(fkclist, cxt->fkconstraints)
		{
			FkConstraint *fkconstraint = (FkConstraint *) lfirst(fkclist);

			fkconstraint->skip_validation = true;
		}

		cxt->alist = lappend(cxt->alist, (Node *) alterstmt);
	}
}

/*
 * transformIndexStmt -
 *	  transforms the qualification of the index statement
 */
static Query *
transformIndexStmt(ParseState *pstate, IndexStmt *stmt)
{
	Query	   *qry;
	RangeTblEntry *rte = NULL;
	List	   *l;

	qry = makeNode(Query);
	qry->commandType = CMD_UTILITY;

	/* take care of the where clause */
	if (stmt->whereClause)
	{
		/*
		 * Put the parent table into the rtable so that the WHERE clause
		 * can refer to its fields without qualification.  Note that this
		 * only works if the parent table already exists --- so we can't
		 * easily support predicates on indexes created implicitly by
		 * CREATE TABLE. Fortunately, that's not necessary.
		 */
		rte = addRangeTableEntry(pstate, stmt->relation, NULL, false, true);

		/* no to join list, yes to namespace */
		addRTEtoQuery(pstate, rte, false, true);

		stmt->whereClause = transformWhereClause(pstate, stmt->whereClause,
												 "WHERE");
	}

	/* take care of any index expressions */
	foreach(l, stmt->indexParams)
	{
		IndexElem  *ielem = (IndexElem *) lfirst(l);

		if (ielem->expr)
		{
			/* Set up rtable as for predicate, see notes above */
			if (rte == NULL)
			{
				rte = addRangeTableEntry(pstate, stmt->relation, NULL,
										 false, true);
				/* no to join list, yes to namespace */
				addRTEtoQuery(pstate, rte, false, true);
			}
			ielem->expr = transformExpr(pstate, ielem->expr);

			/*
			 * We check only that the result type is legitimate; this is
			 * for consistency with what transformWhereClause() checks for
			 * the predicate.  DefineIndex() will make more checks.
			 */
			if (expression_returns_set(ielem->expr))
				ereport(ERROR,
						(errcode(ERRCODE_DATATYPE_MISMATCH),
					   errmsg("index expression may not return a set")));
		}
	}

	qry->hasSubLinks = pstate->p_hasSubLinks;
	stmt->rangetable = pstate->p_rtable;

	qry->utilityStmt = (Node *) stmt;

	return qry;
}

/*
 * transformRuleStmt -
 *	  transform a Create Rule Statement. The actions is a list of parse
 *	  trees which is transformed into a list of query trees.
 */
static Query *
transformRuleStmt(ParseState *pstate, RuleStmt *stmt,
				  List **extras_before, List **extras_after)
{
	Query	   *qry;
	RangeTblEntry *oldrte;
	RangeTblEntry *newrte;

	qry = makeNode(Query);
	qry->commandType = CMD_UTILITY;
	qry->utilityStmt = (Node *) stmt;

	/*
	 * To avoid deadlock, make sure the first thing we do is grab
	 * AccessExclusiveLock on the target relation.	This will be needed by
	 * DefineQueryRewrite(), and we don't want to grab a lesser lock
	 * beforehand.	We don't need to hold a refcount on the relcache
	 * entry, however.
	 */
	heap_close(heap_openrv(stmt->relation, AccessExclusiveLock),
			   NoLock);

	/*
	 * NOTE: 'OLD' must always have a varno equal to 1 and 'NEW' equal to
	 * 2.  Set up their RTEs in the main pstate for use in parsing the
	 * rule qualification.
	 */
	Assert(pstate->p_rtable == NIL);
	oldrte = addRangeTableEntry(pstate, stmt->relation,
								makeAlias("*OLD*", NIL),
								false, true);
	newrte = addRangeTableEntry(pstate, stmt->relation,
								makeAlias("*NEW*", NIL),
								false, true);
	/* Must override addRangeTableEntry's default access-check flags */
	oldrte->checkForRead = false;
	newrte->checkForRead = false;

	/*
	 * They must be in the namespace too for lookup purposes, but only add
	 * the one(s) that are relevant for the current kind of rule.  In an
	 * UPDATE rule, quals must refer to OLD.field or NEW.field to be
	 * unambiguous, but there's no need to be so picky for INSERT &
	 * DELETE. (Note we marked the RTEs "inFromCl = true" above to allow
	 * unqualified references to their fields.)  We do not add them to the
	 * joinlist.
	 */
	switch (stmt->event)
	{
		case CMD_SELECT:
			addRTEtoQuery(pstate, oldrte, false, true);
			break;
		case CMD_UPDATE:
			addRTEtoQuery(pstate, oldrte, false, true);
			addRTEtoQuery(pstate, newrte, false, true);
			break;
		case CMD_INSERT:
			addRTEtoQuery(pstate, newrte, false, true);
			break;
		case CMD_DELETE:
			addRTEtoQuery(pstate, oldrte, false, true);
			break;
		default:
			elog(ERROR, "unrecognized event type: %d",
				 (int) stmt->event);
			break;
	}

	/* take care of the where clause */
	stmt->whereClause = transformWhereClause(pstate, stmt->whereClause,
											 "WHERE");

	if (length(pstate->p_rtable) != 2)	/* naughty, naughty... */
		ereport(ERROR,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
				 errmsg("rule WHERE condition may not contain references to other relations")));

	/* aggregates not allowed (but subselects are okay) */
	if (pstate->p_hasAggs)
		ereport(ERROR,
				(errcode(ERRCODE_GROUPING_ERROR),
				 errmsg("rule WHERE condition may not contain aggregate functions")));

	/* save info about sublinks in where clause */
	qry->hasSubLinks = pstate->p_hasSubLinks;

	/*
	 * 'instead nothing' rules with a qualification need a query
	 * rangetable so the rewrite handler can add the negated rule
	 * qualification to the original query. We create a query with the new
	 * command type CMD_NOTHING here that is treated specially by the
	 * rewrite system.
	 */
	if (stmt->actions == NIL)
	{
		Query	   *nothing_qry = makeNode(Query);

		nothing_qry->commandType = CMD_NOTHING;
		nothing_qry->rtable = pstate->p_rtable;
		nothing_qry->jointree = makeFromExpr(NIL, NULL);		/* no join wanted */

		stmt->actions = makeList1(nothing_qry);
	}
	else
	{
		List	   *oldactions;
		List	   *newactions = NIL;

		/*
		 * transform each statement, like parse_sub_analyze()
		 */
		foreach(oldactions, stmt->actions)
		{
			Node	   *action = (Node *) lfirst(oldactions);
			ParseState *sub_pstate = make_parsestate(pstate->parentParseState);
			Query	   *sub_qry,
					   *top_subqry;
			bool		has_old,
						has_new;

			/*
			 * Set up OLD/NEW in the rtable for this statement.  The
			 * entries are marked not inFromCl because we don't want them
			 * to be referred to by unqualified field names nor "*" in the
			 * rule actions.  We must add them to the namespace, however,
			 * or they won't be accessible at all.  We decide later
			 * whether to put them in the joinlist.
			 */
			oldrte = addRangeTableEntry(sub_pstate, stmt->relation,
										makeAlias("*OLD*", NIL),
										false, false);
			newrte = addRangeTableEntry(sub_pstate, stmt->relation,
										makeAlias("*NEW*", NIL),
										false, false);