From: Robert Klemme <bob.news@...>
Date: 2004-01-12T19:56:36+09:00
Subject: Re: Database applications and OOness


"gabriele renzi" <surrender_it@remove.yahoo.it> schrieb im Newsbeitrag
news:52cuvv0cbjq9q4q8k65q5hhei3770ltbgf@4ax.com...
> il Sat, 10 Jan 2004 07:18:53 +0900, "Weirich, James"
> <James.Weirich@FMR.COM> ha scritto::
>
>
> >DBI is that common interface (and is modelled on the Perl DBI ... I
suspect
> >Python's is likewise modelled on Perls).
>
> right. but every dbms binding has a different basic api. Why this
> useless duplication?
> (Probably that may be useful, and I'm just too stupid to understand
> why)

Just for connecting etc.  The querying part is identical.  Typically you
would centralize the connection creation code and have querying etc.
somewhere else where you just hand over a live connection.  Then you can
exchange the dbs as easily as possible (i.e. SQL syntax issues for
specialized queries still have to be changed, but basic CRUD operations
will work without change).  IMHO it is not feasible to build a unified DB
API.  JDBC goes quite far but not much further than DBI: the only parts
where JDBC is better with respect to a unified API is the definition of
certain escape sequences for data and time formats and stored procedure
invocation among some others.

See here for the JDBS style escaping:
http://java.sun.com/j2se/1.4.1/docs/guide/jdbc/getstart/statement.html#999472

> >DBI comes with a set of drivers
> >(DBDs) for each type of database supported.  The DBDs each talk to the
> >native C API library to access the actual database. I think you are
> >advocating merging the DBD and the native library into one entity, but
I'm
> >not sure what that would accomplish.
>
> I'm pushing the elimination of a level of indirection.
>  Why  a wrapper library(an additional pkg, additional version
> matching, distribution pains, api to learn, maybe slowness cause dbi
> is pure ruby) + a native library, if we could have just native
> libraries?

I don't know what wrapper you are talking about.  One level of wrapping
(i.e. what DBI does) is appropriate and nicely to use.

> When you have stuff that you may simplify you refactor, am I right? ;)

Of course.

Regards

    robert