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Re: [stellation-res] Database abstraction
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Hi,
why not use XML/XSLT? It seems like a natural choice to me?!
It would be nice to define the structure of the database as an xml-schema
and generate the DDL from that using XSLT. The Stylesheet could come with an
extra style sheet per database to store the keywords specific to a particular
database vendor.
What do you think?
Mariano
>
> So... I'm looking at trying to create a database abstraction layer that
> will work accross Postgres, DB2, Oracle, MySQL/InnoDB, and
> Firebird.
>
> One option is to totally automate the SQL generation process. This
> allows us to smoothly handle things like the INNODB declarations
> that need to go onto the end of table creations, variations in typenames,
> etc.
>
> I've tried a first cut at doing this for table creation. I'm looking at a
>
> bit of test code, and I can't decide whether I like it (it's nicely abstr
> act,
> and quite easy to write), or hate it (it's hard to see the SQL in it). He
> re's
> a sample: what do you folks think: is this a good direction, or am I bein
> g
> idiotically abstract?
>
> Here's the original SQL:
>
> CREATE TABLE Properties (INTEGER aid,
> INTEGER vid,
> INTEGER inheritable,
> VARCHAR(200) name,
> VARCHAR(1600) value,
> CONSTRAINT fk3 FOREIGN KEY (aid, vid) REFERENCES Versions(aid, v
> id)
> PRIMARY KEY(aid, vid, name))
>
>
> Here's the corresponding code:
> DatabaseCreateTableCommand cmd =
> _db.createTable("Properties")
> .addIntegerField("aid")
> .addIntegerField("vid")
> .addIntegerField("inheritable")
> .addShortStringField("name")
> .addLongStringField("value")
> .beginForeignKeyConstraint("fk3", "FOREIGN KEY")
> .addConstraintField("aid")
> .addConstraintField("vid")
> .beginForeignKeyReferences("Versions")
> .addConstraintField("aid")
> .addConstraintField("vid")
> .endForeignKeyConstraint()
> .beginPrimaryKeyConstraint()
> .addConstraintField("aid")
> .addConstraintField("vid")
> .addConstraintField("name")
> .endPrimaryKeyConstraint()
> .endCommand();
>
> --
> Mark Craig Chu-Carroll, IBM T.J. Watson Research Center
> *** The Stellation project: Advanced SCM for Collaboration
> *** http://www.eclipse.org/stellation
> *** Work Email: mcc@xxxxxxxxxxxxxx ------- Personal Email: markcc@bestwe
> b.net
>
>
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