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Posted to modperl@perl.apache.org by Michael Nachbaur <MN...@rei.com> on 2000/07/28 17:33:57 UTC
[OT] Abstract-Database Class
<Warn priority="low">
<warning class="Off Topic"/>
<warning class="Long"/>
</Warn>
I'm not exactly sure where to send this, but here it goes:
Has anyone completed/started an abstract database class at all? I've written some for very specific applications, but I want a more general-purpose tool. I'm about to start development on one, but wanted to get feedback from the world-at-large to see what features you would want first (or if anyone has already started one).
The classes I've created/used before, are like:
my $order = new Order( oid => '1234567' );
$order->fetch();
foreach my $order_line ( $order->Lines ) {
print $order_line->Description, $order_line->Price;
}
I'd like to interact with a database, update data, save data, etc. without having to actually call any SQL code. And, if I modify my database schema, I'd like the classes to automatically adapt.
The way I've done this before, is create a series of classes with AUTOLOAD subs in them which intercept the name of the method being called, and then updating that specific field in the record.
How I"d like to implement it would be to define an XML file with represents the way my data is structured in the database. This way, the objects can determine when to cache data, and when to commit its values to the database for maximum efficiency. An example could be:
<schema name="mp3_site" database="DB0" database_vendor="Oracle" database_version="8.1.5" username="nachbaur" password="you_wish">
<table name="artist" primary_key="id">
<field name="name" type="varchar" size="256" options="not null">
</table>
<table name="album" primary_key="id">
<field name="parent_id" references="artist" options="not null"/>
<field name="name" type="varchar" size="256" options="not null"/>
<field name="image" type="varchar" size="4000" />
</table>
<table name="track" primary_key="id">
<field name="parent_id" references="album" options="not null"/>
<field name="name" type="varchar" size="256" options="not null"/>
<field name="filename" type="varchar" size="4000"/>
<field name="filesize" type="integer"/>
</table>
</schema>
Now, obviously thats not that perfect of an example (but I"m in a hurry, 'cause I need to go get some coffee), but it illustrates that the class could import that XML file, which defines the way it should interpret data. So, it could fetch a particular record, and depending on how you tell it to operate, it could suck down all the data that the inital record refers to, or could retrieve it as-needed.
It may not operate as efficiently as possible by default, but would give much more flexibility to the programmer. I know that when I'm lazy, I don't want to bind all my values, and make sure I'm using optimized SQL statements (explain plan, and that sorta thing). With this, I could "pre-define" SQL statements in this XML file that are pre-optimized, and I can just say:
$db->run('do_really_scarry_join', %options);
Sory for the long message. Would anyone like a module like this, or would I be just wasting my time? Anyone already have something like this? Any feedback would be appreciated (except flames and spam).
--man
Michael A. Nachbaur (KE6WIA)
mike(at)nachbaur(dot)com
http://www.nachbaur.com
"Only two things are infinite, the universe and human stupidity, and I'm not sure about the former." - Albert Einstein
RE: [OT] Abstract-Database Class
Posted by mgraham <mg...@toronto.circadence.com>.
There's a mailing list set up at sourceforge for discussing
object-persistence issues and tools for use with perl:
http://mail1.sourceforge.net/mailman/listinfo/poop-group
Michael
Re: [OT] Abstract-Database Class
Posted by Eric Prud'hommeaux <er...@w3.org>.
On Fri, Jul 28, 2000 at 08:33:57AM -0700, Michael Nachbaur wrote:
> <Warn priority="low">
> <warning class="Off Topic"/>
> <warning class="Long"/>
> </Warn>
>
> I'm not exactly sure where to send this, but here it goes:
> Has anyone completed/started an abstract database class at all? I've written some for very specific applications, but I want a more general-purpose tool. I'm about to start development on one, but wanted to get feedback from the world-at-large to see what features you would want first (or if anyone has already started one).
>
> The classes I've created/used before, are like:
> my $order = new Order( oid => '1234567' );
> $order->fetch();
> foreach my $order_line ( $order->Lines ) {
> print $order_line->Description, $order_line->Price;
> }
>
> I'd like to interact with a database, update data, save data, etc. without having to actually call any SQL code. And, if I modify my database schema, I'd like the classes to automatically adapt.
>
> The way I've done this before, is create a series of classes with AUTOLOAD subs in them which intercept the name of the method being called, and then updating that specific field in the record.
>
> How I"d like to implement it would be to define an XML file with represents the way my data is structured in the database. This way, the objects can determine when to cache data, and when to commit its values to the database for maximum efficiency. An example could be:
I have an object database abstraction that I use for a bunch of stuff, including a set of RDF libraries. "object" is a perl datastructure defined by an SQL table. The purpose of ObjectDB is to allow programs to store objects, create objects, load objects from the DB (including all objects linked via external keys) and cache the DB interactions to keep it all efficient. The bulk of the work is in an importer that reads a database structure and generates a .pm with class defs, and a bunch of code for handling the implications of unique indexes.
Take a look at http://www.w3.org/1999/02/26-modules/ and http://dev.w3.org/cvsweb/perl/modules/W3C/Database/ to see if you are interested in leveraging off ObjectDB or just ripping off code.
--
-eric
(eric@w3.org)
RE: [OT] Abstract-Database Class
Posted by jb...@team-linux.com.
Look at Michael Schwern's Class::DBI on CPAN.
On 28-Jul-2000 Michael Nachbaur wrote:
> <Warn priority="low">
> <warning class="Off Topic"/>
> <warning class="Long"/>
> </Warn>
>
> I'm not exactly sure where to send this, but here it goes:
> Has anyone completed/started an abstract database class at all? I've written
> some for very specific applications, but I want a more general-purpose tool.
> I'm about to start development on one, but wanted to get feedback from the
> world-at-large to see what features you would want first (or if anyone has
> already started one).
>
> The classes I've created/used before, are like:
> my $order = new Order( oid => '1234567' );
> $order->fetch();
> foreach my $order_line ( $order->Lines ) {
> print $order_line->Description, $order_line->Price;
> }
>
> I'd like to interact with a database, update data, save data, etc. without
> having to actually call any SQL code. And, if I modify my database schema,
> I'd like the classes to automatically adapt.
>
> The way I've done this before, is create a series of classes with AUTOLOAD
> subs in them which intercept the name of the method being called, and then
> updating that specific field in the record.
>
> How I"d like to implement it would be to define an XML file with represents
> the way my data is structured in the database. This way, the objects can
> determine when to cache data, and when to commit its values to the database
> for maximum efficiency. An example could be:
> <schema name="mp3_site" database="DB0" database_vendor="Oracle"
> database_version="8.1.5" username="nachbaur" password="you_wish">
> <table name="artist" primary_key="id">
> <field name="name" type="varchar" size="256" options="not null">
> </table>
> <table name="album" primary_key="id">
> <field name="parent_id" references="artist" options="not null"/>
> <field name="name" type="varchar" size="256" options="not null"/>
> <field name="image" type="varchar" size="4000" />
> </table>
> <table name="track" primary_key="id">
> <field name="parent_id" references="album" options="not null"/>
> <field name="name" type="varchar" size="256" options="not null"/>
> <field name="filename" type="varchar" size="4000"/>
> <field name="filesize" type="integer"/>
> </table>
> </schema>
>
> Now, obviously thats not that perfect of an example (but I"m in a hurry,
> 'cause I need to go get some coffee), but it illustrates that the class could
> import that XML file, which defines the way it should interpret data. So, it
> could fetch a particular record, and depending on how you tell it to operate,
> it could suck down all the data that the inital record refers to, or could
> retrieve it as-needed.
>
> It may not operate as efficiently as possible by default, but would give much
> more flexibility to the programmer. I know that when I'm lazy, I don't want
> to bind all my values, and make sure I'm using optimized SQL statements
> (explain plan, and that sorta thing). With this, I could "pre-define" SQL
> statements in this XML file that are pre-optimized, and I can just say:
> $db->run('do_really_scarry_join', %options);
>
> Sory for the long message. Would anyone like a module like this, or would I
> be just wasting my time? Anyone already have something like this? Any
> feedback would be appreciated (except flames and spam).
>
> --man
> Michael A. Nachbaur (KE6WIA)
> mike(at)nachbaur(dot)com
> http://www.nachbaur.com
> "Only two things are infinite, the universe and human stupidity, and I'm not
> sure about the former." - Albert Einstein
--
Jason Bodnar + jbodnar@team-linux.com + Team Linux
Oh, well, of course, everything looks bad if you remember it.
-- Homer Simpson
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