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Change the row constructor syntax (ROW(...)) so that list elements foo.*

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will be expanded to a list of their member fields, rather than creating
a nested rowtype field as formerly.  (The old behavior is still available
by omitting '.*'.)  This syntax is not allowed by the SQL spec AFAICS,
so changing its behavior doesn't violate the spec.  The new behavior is
substantially more useful since it allows, for example, triggers to check
for data changes with 'if row(new.*) is distinct from row(old.*)'.  Per
my recent proposal.
This commit is contained in:
Tom Lane
2006-06-26 17:24:41 +00:00
parent 4b98d423d7
commit ca0d2197ca
6 changed files with 219 additions and 26 deletions
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40
src/backend/parser/parse_expr.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.192 2006/04/22 01:26:00 tgl Exp $
* $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.193 2006/06/26 17:24:41 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -29,6 +29,7 @@
#include "parser/parse_func.h"
#include "parser/parse_oper.h"
#include "parser/parse_relation.h"
#include "parser/parse_target.h"
#include "parser/parse_type.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
@ -1289,6 +1290,43 @@ transformRowExpr(ParseState *pstate, RowExpr *r)
Node *e = (Node *) lfirst(arg);
Node *newe;
/*
* Check for "something.*". Depending on the complexity of the
* "something", the star could appear as the last name in ColumnRef,
* or as the last indirection item in A_Indirection.
*/
if (IsA(e, ColumnRef))
{
ColumnRef *cref = (ColumnRef *) e;
if (strcmp(strVal(llast(cref->fields)), "*") == 0)
{
/* It is something.*, expand into multiple items */
newargs = list_concat(newargs,
ExpandColumnRefStar(pstate, cref,
false));
continue;
}
}
else if (IsA(e, A_Indirection))
{
A_Indirection *ind = (A_Indirection *) e;
Node *lastitem = llast(ind->indirection);
if (IsA(lastitem, String) &&
strcmp(strVal(lastitem), "*") == 0)
{
/* It is something.*, expand into multiple items */
newargs = list_concat(newargs,
ExpandIndirectionStar(pstate, ind,
false));
continue;
}
}
/*
* Not "something.*", so transform as a single expression
*/
newe = transformExpr(pstate, e);
newargs = lappend(newargs, newe);
}