volunteer wanted to write a few FAQ entries about Mnesia

Chandrashekhar Mullaparthi <>
Mon Feb 24 13:58:13 CET 2003


mnesia:match_object 
mnesia:select 

achieve this, but you are right, there is no explicit concept of aggregate
keys.

Chandru

-----Original Message-----
From: Chris Pressey [mailto:]
Sent: 21 February 2003 22:05
To: Ulf Wiger
Cc: ; 
Subject: Re: volunteer wanted to write a few FAQ entries about Mnesia


On Fri, 21 Feb 2003 11:53:02 +0100 (MET)
Ulf Wiger <> wrote:

> On Thu, 20 Feb 2003, Chris Pressey wrote:
> 
> >Records are accessed by a single key (which may be unique
> >or duplicate) and there is no concept of a secondary key.
> 
> Actually there is. You can define an index on a non-key
> attribute, and access records using mnesia:index_read/3 or
> index_match_object/2.

Oops!  I meant there is no concept of an aggregate key, i.e. of using
multiple fields to identify a record.

-Chris



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