Re: [boost] Re: Serialization to relational table

From: Joachim Achtzehnter (joachim_at_[hidden])
Date: 2002-11-18 17:01:34

Today, in a message to boost, Vladimir Prus wrote:
>
> Bohdan wrote:
> >
> > serialization: Object <-> Relational tuple (object-relational mapping).
>
> Wouldn't there be a problem with converting object with variable size?
> How can you store vector<int> in a relational database? I don't see an
> easy way.

You are raising a good point. What this ultimately boils down to is the
realization that mapping Object to Tuple is problematic.

This doesn't mean that the relational model is a bad choice as a target
model for a persistent store. On the contrary, it is probably the best
model to use for this purpose. The problem is only the assumption that
Object (or better: type) maps always to Tuple. Recent developments in
relational theory suggest that it is the Domain concept ("column type")
that should be seen as the closest equivalent to "Object Type". Refer to
recent writings by Chris Date (books and also papers, the latter
accessible on the Web) for the theory behind this, and why the Object <=>
Tuple identification is a mistake.

Joachim

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