diff options
Diffstat (limited to 'src/include/nodes/parsenodes.h')
| -rw-r--r-- | src/include/nodes/parsenodes.h | 46 |
1 files changed, 40 insertions, 6 deletions
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h index 996c2b9c738..9ae9feb739d 100644 --- a/src/include/nodes/parsenodes.h +++ b/src/include/nodes/parsenodes.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $Id: parsenodes.h,v 1.159 2002/03/08 04:37:18 tgl Exp $ + * $Id: parsenodes.h,v 1.160 2002/03/12 00:52:01 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -430,9 +430,12 @@ typedef struct TargetEntry * RangeTblEntry - * A range table is a List of RangeTblEntry nodes. * - * Currently we use the same node type for both plain relation references - * and sub-selects in the FROM clause. It might be cleaner to abstract - * the common fields into a "superclass" nodetype. + * A range table entry may represent a plain relation, a sub-select in + * FROM, or the result of a JOIN clause. (Only explicit JOIN syntax + * produces an RTE, not the implicit join resulting from multiple FROM + * items. This is because we only need the RTE to deal with SQL features + * like outer joins and join-output-column aliasing.) Other special + * RTE types also exist, as indicated by RTEKind. * * alias is an Attr node representing the AS alias-clause attached to the * FROM expression, or NULL if no clause. @@ -445,7 +448,7 @@ typedef struct TargetEntry * * inh is TRUE for relation references that should be expanded to include * inheritance children, if the rel has any. This *must* be FALSE for - * subquery RTEs. + * RTEs other than RTE_RELATION entries. * * inFromCl marks those range variables that are listed in the FROM clause. * In SQL, the query can only refer to range variables listed in the @@ -465,12 +468,28 @@ typedef struct TargetEntry * (This allows rules to act as setuid gateways.) *-------------------- */ +typedef enum RTEKind +{ + RTE_RELATION, /* ordinary relation reference */ + RTE_SUBQUERY, /* subquery in FROM */ + RTE_JOIN, /* join */ + RTE_SPECIAL /* special rule relation (NEW or OLD) */ +} RTEKind; + typedef struct RangeTblEntry { NodeTag type; + RTEKind rtekind; /* see above */ + /* - * Fields valid for a plain relation RTE (else NULL/zero): + * XXX the fields applicable to only some rte kinds should be merged + * into a union. I didn't do this yet because the diffs would impact + * a lot of code that is being actively worked on. FIXME later. + */ + + /* + * Fields valid for a plain relation or inh_relation RTE (else NULL/zero): */ char *relname; /* real name of the relation */ Oid relid; /* OID of the relation */ @@ -481,6 +500,21 @@ typedef struct RangeTblEntry Query *subquery; /* the sub-query */ /* + * Fields valid for a join RTE (else NULL): + * + * joincoltypes/joincoltypmods identify the column datatypes of the + * join result. joinleftcols and joinrightcols identify the source + * columns from the join's inputs: each entry is either a source column + * AttrNumber or zero. For normal columns exactly one is nonzero, + * but both are nonzero for a column "merged" by USING or NATURAL. + */ + JoinType jointype; /* type of join */ + List *joincoltypes; /* integer list of column type OIDs */ + List *joincoltypmods; /* integer list of column typmods */ + List *joinleftcols; /* integer list of left-side column #s */ + List *joinrightcols; /* integer list of right-side column #s */ + + /* * Fields valid in all RTEs: */ Attr *alias; /* user-written alias clause, if any */ |