Re: Proposal: variant of regclass

> On Tue, Jan 14, 2014 at 9:28 AM, Yugo Nagata <nagata@sraoss.co.jp> wrote:
>> Here is the patch to implement to_regclass, to_regproc, to_regoper,
>> and to_regtype.
> 
> + static Datum regclass_guts(char *class_name_or_oid, bool raiseError);
> 
> Minor bikeshedding, a lot of code currently uses an argument named
> "missing_ok" for this purpose (with inverse meaning of course). Any
> reasons why you chose "raiseError" instead?

Originally the proposal checks errors like syntactical one in addition
to missing objects. So I think "raiseError" was more appropriate at
that time. Now they only check missing objects. So renaming to
"missing_ok" could be more appropriate.

> I only had a brief look at the patch, so maybe I'm missing something.
> But I don't think you should create 3 variants of these functions:
> * parseTypeString calls parseTypeString_guts with false
> * parseTypeStringMissingOk calls parseTypeString_guts with true
> * parseTypeString_guts
> 
> And this is just silly:
> 
> if (raiseError)
>     parseTypeString(typ_name_or_oid, &result, &typmod);
> else
>     parseTypeStringMissingOk(typ_name_or_oid, &result, &typmod);
> 
> Just add an argument to parseTypeString and patch all the callers.

Leave the disccusion to Yugo..

>> if requested object is not found,
>> returns InvalidOid, rather than raises an error.
> 
> I thought the consensus was that returning NULL is better than
> InvalidOid? From an earlier message:
> 
> On Thu, Dec 5, 2013 at 5:25 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>> Another advantage of this approach is that, IIUC, type input functions
>> can't return a NULL value.  So 'pg_klass'::regclass could return 0,
>> but not NULL.  On the other hand, toregclass('pg_klass') *could*
>> return NULL, which seems conceptually cleaner.

Not sure. There's already at least one counter example:

pg_my_temp_schema()    oid    OID of session's temporary schema, or 0 if none

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
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