From: David Vallner <david@...>
Date: 2006-10-20T19:10:29+09:00
Subject: Re: Storing a Hash in a database table using YAML--anything better?

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J. B. Rainsberger wrote:
> I want to store a hash as a single row in a database table. I'm
> currently storing each name/value pair as a row with a reference back t=
o
> the "parent" row, but that seems unnecessarily complex. I want to know
> whether you have any better suggestions than what I plan to try to do.
>=20

Disclaimer: A lot of the following will be database access performance
related. In personal code with low usage, those can be safely ignored,
but for a self-education project, I prefer following good practices to
learn them even if they seem clunky.

What's the structure of the hash? If it could be replaced by a data
structure, I'd do so and keep this approach (it IS the correct one from
the relational data modelling point of view), unless you're sure the
hash is an atomic value object by design.

I'd especially not use the serialization approach if you need to filter
your data according to the contents of that hash - the "draw all records
from the DB and filter them in Ruby" approach makes baby DBA Jesus cry
and is a good candidate for becoming a bottleneck. I'd also not use the
serialization approach if it's binary serialisation - if you ever had to
access the database from anything except Rails (e.g. Crystal Reports),
you're screwed.

David Vallner


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