[erlang-questions] How to return all records in dets

[lloyd@REDACTED]

Hi Ulf,

No cigar.

First I tried in Erlang shell:

(nitrogen@REDACTED)36> visitor_store:open_visitor_db().
dets opened: visitors
void
(nitrogen@REDACTED)37> dets:tab2list(visitors).
** exception error: undefined function dets:tab2list/1

(I'm running R17.0; noticed that tab2list/1 is not in docs. We do have to_ets/1, but I haven't tried that yet.)


(nitrogen@REDACTED)38> dets:select(visitors, [{'_',[], ['$_']}]).
** exception error: bad argument
     in function  dets:select/2
        called as dets:select(visitors,[{'_',[],['$_']}])

(Maybe my typo, but I can't see it.)

(nitrogen@REDACTED)39> dets:match_object(visitors, '_').
** exception error: bad argument
     in function  dets:match_object/2
        called as dets:match_object(visitors,'_')

So I created some functions:

dump_visitors() ->
   dets:tab2list(visitors).

dump_visitors1() ->
   dets:select(visitors, [{'_', [], ['$_']}]).

dump_visitors2() ->
   dets:match_object(visitors, '_').

And called them in the shell:

(nitrogen@REDACTED)40> l(visitor_store).
{module,visitor_store}

(nitrogen@REDACTED)41> visitor_store:dump_visitors().
** exception error: undefined function dets:tab2list/1

(nitrogen@REDACTED)42> visitor_store:dump_visitors1().
** exception error: bad argument
     in function  dets:select/2
        called as dets:select(visitors,[{'_',[],['$_']}])

(nitrogen@REDACTED)43> visitor_store:dump_visitors2().
** exception error: bad argument
     in function  dets:match_object/2
        called as dets:match_object(visitors,'_')

I feel like I'm jinxed.

Thanks,

Lloyd




-----Original Message-----
From: "Ulf Wiger" <ulf@REDACTED>
Sent: Friday, May 30, 2014 4:08pm
To: lloyd@REDACTED
Cc: "erlang questions" <erlang-questions@REDACTED>
Subject: Re: [erlang-questions] How to return all records in dets


ets:tab2list(Tab).

ets:select(Tab, [{‘_’, [], [‘$_’]}]).

ets:select(Tab, ets:fun2ms(fun(X) -> X end).

ets:match_object(Tab, ‘_’)

BR,
Ulf W

On 30 May 2014, at 21:56, lloyd@REDACTED wrote:

> Hello,
> 
> I'm cross-eyed from looking at match specifications. All I want to do is list all records in my small dets table. I once ran across a very neat query to accomplish that, but for the life can't Google it up.
> 
> Can some kind soul give me a query that works?
> 
> Many thanks,
> 
> LRP 
> 
> 
> 
> _______________________________________________
> erlang-questions mailing list
> erlang-questions@REDACTED
> http://erlang.org/mailman/listinfo/erlang-questions

Ulf Wiger, Co-founder & Developer Advocate, Feuerlabs Inc.
http://feuerlabs.com