[odb-users] Index on subtable column "index"

[Tim Tao]

Hi Boris,

Thanks for your reply.

Another question about the subtable.

I notice all the subtables don't have primary key. I don't know if I can use the combination of parent table's primary key and "index" as the primary key of the subtable? Is there any reason we don't want to do that.

Thanks !

Tim
________________________________________
From: Boris Kolpackov <boris at codesynthesis.com>
Sent: Monday, September 21, 2015 10:01 AM
To: Tim Tao
Cc: odb-users at codesynthesis.com
Subject: Re: [odb-users] Index on subtable column "index"

Hi Tim,

Tim Tao <Tim.Tao at akunacapital.com> writes:

> I got a question about ODB subtable, so when we declare a container,
> e.g vector, in an ODB object, it will create a subtable for this
> container and a new column "index" with it, which is a very good
> design I think, but I am wondering why ODB will also add an index
> on this "index" column, is there any performance consideration?

Yes, the SELECT statement that loads the elements of the container,
has the 'ORDER BY index' clause.

Boris
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Tim Tao | Junior Developer

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