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Re: [Erw-devel] referential integrity , model update

From: erw-devel
Subject: Re: [Erw-devel] referential integrity , model update
Date: 30 Oct 2003 17:27:36 +0100

On Thu, 2003-10-30 at 13:49, address@hidden wrote:

> [1] I did not see any support in ERL for referential integrity. However 
> are delete and update rules specified?

In which sense? ERW maintains referential integrity. The introduction to
the documentation explains the policy on deletions (cascaded for weak
entity types, forbidden for mandatory relationship types).

> [2] What happens to one's data and schema should the data model need 
> updating?

You have the two generated SQL scripts, and some tools to check that the
database corresponds to the definitions. If you just add attributes,
types, etc. it's just a matter of extracting the relevant information
from the SQL and send it to the database. We do this monthly or so.

Automatic data migration is, of course, out of discussion 8^).

> [3] What databases does ERL deploy to?

Everything supported by PEAR (hopefully).



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