Re: [Modeling-users] Re: Implementing inheritance through vertical mapping

[Ernesto R. <er...@si...>]

----- Original Message -----=20
From: "Sebastien Bigaret" <sbi...@us...>
To: "Federico Heinz" <fh...@vi...>
Cc: "Modeling Mailing List" <mod...@li...>
Sent: Thursday, September 25, 2003 3:37 PM
Subject: [Modeling-users] Re: Implementing inheritance through vertical =
mapping
.....
>> [1] depending on priorities. We have done similar work in other
>> contexts, but for now we could choose to use PostgreSQL's inheritance
>> mechanism to implement the database, until we can spare the time to
>> create the vertical mapping layer.

>Could you possibly elaborate on that? I never played with postgresql's
>inheritance support, and it's probably something that could be added in
>the User's Guide until vertical mapping is supported. If you find some
>time to illustrate the mechanisms, I'll be interested in learning how
>they behave wrt. the framework.

Take into account that in PostgreSQL inherited tables have separate =
primary key sets and that, AFAIK, referential integrity rules in base =
tables are not checked. So the only inheritance mechanism implemented is =
that of queries. All other questions are still open and although =
possible solutions have been discussed, nothing has been done for years. =
One of the most important problems seems that an index covers only one =
table, so all DML queries (INSERT, DELETE, UPDATE) have to check the =
indexes for the complete inheritance tree, what, I think, is not =
implemented.

Erny