object-relational mappers

[hdante]

On Apr 2, 8:25 am, Bruno Desthuilliers <bruno.
42.desthuilli... at websiteburo.invalid> wrote:
> hdante a écrit :
>
>
>
>
> >  Try Rails' ActiveRecord. Your problems should reduce to (lg lg
> > 2)^(1/12).
>
> Correct me if I'm wrong, but IIRC ActiveRecord requires you use numeric
> auto_increment fields for primary key. As far as I'm concerned, this is
> a definitive no-no.

 Why is that so bad ?

 "But wait !, you cry. Shouldn't the primary key of my orders table be
the order number or some other meaningful column ? Why use an
artificial primary key such as id ? The reason is largely a practical
one - the format of external data may change over time."
 (...)
 "Normally, Active Record takes care of creating new primary key
values for records that you create and add to the database - they'll
be ascending integers (possibily with some gaps in the sequence).
However, if you override the primary key column's name, you also take
on the responsibility of setting the primary key to a unique value
before you save a new row."
                                   -- AWDWR

>
> >  Seriously, you'll forget there's a relational database below.
>
> Why on earth are you using a RDBMS if you don't want it ? I for one *do*
> care about using a *relational* database, and *don't* want to hide it
> away. What I don't want is to have to build my queries as raw strings.
> And that's where SQLAlchemy shines : it's not primarily an "ORM", it's
> an higher-level Python/SQL integration tool that let you build your
> queries as Python objects (and also, eventually, build an ORM if you
> want to...).


 "Some object-relational mappers seek to eliminate the use of SQL
entirely, hoping for object-oriented purity by forcing all queries
through an OO layer. Active Record does not. It was built on the
notion that SQL is neither dirty nor bad, just verbose in the trivial
cases. (...) Therefore, you shouldn't feel guilty when you use
find_by_sql to handle either performance bottlenecks or hard queries.
Start out using the object-oriented interface for productivity and
pleasure, and then dip beneath the surface for a close-to-the-metal
experience when you need to do so."
                                   -- AWDWR

 PS. That's okay to use a RDBMS. What I don't want is to use two
programming paradigms, especially, considering the "object-relational
impedance mismatch".