diff options
Diffstat (limited to 'src/backend/optimizer/util/clauses.c')
| -rw-r--r-- | src/backend/optimizer/util/clauses.c | 28 |
1 files changed, 17 insertions, 11 deletions
diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c index 1ab09217c59..876a0dafb72 100644 --- a/src/backend/optimizer/util/clauses.c +++ b/src/backend/optimizer/util/clauses.c @@ -7,7 +7,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.50 1999/08/26 05:09:05 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.51 1999/09/09 02:35:53 tgl Exp $ * * HISTORY * AUTHOR DATE MAJOR EVENT @@ -116,7 +116,10 @@ make_opclause(Oper *op, Var *leftop, Var *rightop) * * Returns the left operand of a clause of the form (op expr expr) * or (op expr) - * NB: it is assumed (for now) that all expr must be Var nodes + * + * NB: for historical reasons, the result is declared Var *, even + * though many callers can cope with results that are not Vars. + * The result really ought to be declared Expr * or Node *. */ Var * get_leftop(Expr *clause) @@ -549,8 +552,11 @@ NumRelids(Node *clause) * if the "something" is a constant, the value of the constant * flags indicating whether a constant was found, and on which side. * Default values are returned if the expression is too complicated, - * specifically -1 for the relid and attno, 0 for the constant value. - * Note that InvalidAttrNumber is *not* -1, but 0. + * specifically 0 for the relid and attno, 0 for the constant value. + * + * Note that negative attno values are *not* invalid, but represent + * system attributes such as OID. It's sufficient to check for relid=0 + * to determine whether the routine succeeded. */ void get_relattval(Node *clause, @@ -610,8 +616,8 @@ get_relattval(Node *clause, { /* Duh, it's too complicated for me... */ default_results: - *relid = -1; - *attno = -1; + *relid = 0; + *attno = 0; *constval = 0; *flag = 0; return; @@ -663,7 +669,7 @@ static int is_single_func(Node *node) * for a joinclause. * * If the clause is not of the form (var op var) or if any of the vars - * refer to nested attributes, then -1's are returned. + * refer to nested attributes, then zeroes are returned. * */ void @@ -674,10 +680,10 @@ get_rels_atts(Node *clause, AttrNumber *attno2) { /* set default values */ - *relid1 = -1; - *attno1 = -1; - *relid2 = -1; - *attno2 = -1; + *relid1 = 0; + *attno1 = 0; + *relid2 = 0; + *attno2 = 0; if (is_opclause(clause)) { |