diff options
Diffstat (limited to 'src/include/nodes/primnodes.h')
| -rw-r--r-- | src/include/nodes/primnodes.h | 23 |
1 files changed, 13 insertions, 10 deletions
diff --git a/src/include/nodes/primnodes.h b/src/include/nodes/primnodes.h index 2ca40e8ceca..f5cd6ea461d 100644 --- a/src/include/nodes/primnodes.h +++ b/src/include/nodes/primnodes.h @@ -10,7 +10,7 @@ * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $Id: primnodes.h,v 1.51 2001/01/24 19:43:26 momjian Exp $ + * $Id: primnodes.h,v 1.52 2001/02/14 21:35:05 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -29,7 +29,7 @@ typedef struct FunctionCache *FunctionCachePtr; * ---------------------------------------------------------------- */ -/* +/*-------------------- * Resdom (Result Domain) * * Notes: @@ -50,7 +50,7 @@ typedef struct FunctionCache *FunctionCachePtr; * * Both reskey and reskeyop are typically zero during parse/plan stages. * The executor does not pay any attention to ressortgroupref. - * + *-------------------- */ typedef struct Resdom { @@ -129,7 +129,6 @@ typedef struct Expr * list. But varnoold/varoattno continue to hold the original values. * The code doesn't really need varnoold/varoattno, but they are very useful * for debugging and interpreting completed plans, so we keep them around. - * ---------------- */ #define INNER 65000 #define OUTER 65001 @@ -153,7 +152,7 @@ typedef struct Var AttrNumber varoattno; /* original value of varattno */ } Var; -/* +/*-------------------- * Oper * * NOTE: in the good old days 'opno' used to be both (or either, or @@ -169,7 +168,7 @@ typedef struct Var * Note also that opid is not necessarily filled in immediately on creation * of the node. The planner makes sure it is valid before passing the node * tree to the executor, but during parsing/planning opid is typically 0. - * + *-------------------- */ typedef struct Oper { @@ -499,10 +498,14 @@ typedef struct RangeTblRef * are not equivalent to ON() since they also affect the output column list. * * alias is an Attr node representing the AS alias-clause attached to the - * join expression, or NULL if no clause. During parse analysis, colnames - * is filled with a list of String nodes giving the column names (real or - * alias) of the output of the join, and colvars is filled with a list of - * expressions that can be copied to reference the output columns. + * join expression, or NULL if no clause. NB: presence or absence of the + * alias has a critical impact on semantics, because a join with an alias + * restricts visibility of the tables/columns inside it. + * + * During parse analysis, colnames is filled with a list of String nodes + * giving the column names (real or alias) of the output of the join, + * and colvars is filled with a list of expressions that can be copied to + * reference the output columns. *---------- */ typedef struct JoinExpr |