Re: Using database objects in different schemas
Re: Using database objects in different schemas
- Subject: Re: Using database objects in different schemas
- From: Chuck Hill <email@hidden>
- Date: Fri, 15 Dec 2017 19:47:49 +0000
- Thread-topic: Using database objects in different schemas
I think you can make it work, but it is going to need a database connection for
each slave. And there can’t be relationships between slaves or between the
master and the slave. And it is going to be susceptible to “bad assumption”
errors in Wonder (I think that version of EOF is OK).
What you would need to do is to create a new EOModelGroup for each slave and
copy (not a reference, a brand new object) the models into it, adding the
schema to the table names. That avoids the need to tweak the SQL. They you
need to create a new EOObjectStoreCoordinator for each of these groups.
EOObjectStoreCoordinators don’t co-operate so the duplicate GID should be OK.
Then make sure that your code uses the correct EOObjectStoreCoordinator to
create EOEditingContexts in.
I *think* that will work, I have never tried it. Using the
EOSharedEditingContext with objects in the slave tables is going to challenging
as a lot of code is going to assume that there is only one, not per
EOObjectStoreCoordinator. I’d avoid the EOSharedEditingContext. The other
place where you may run into problems is notifications that are not scoped to
the EOObjectStoreCoordinator.
But all in all, this is not really what EOF is meant for. With EOF you would
use a different data model for this sort of multi-tenant solution.
Chuck
From: Webobjects-dev
<webobjects-dev-bounces+chill=email@hidden> on behalf of Paul
Hoadley <email@hidden>
Date: Friday, December 15, 2017 at 2:22 AM
To: André Rothe <email@hidden>
Cc: WebObjects-Dev <email@hidden>
Subject: Re: Using database objects in different schemas
Hi André,
On 15 Dec 2017, at 6:33 pm, André Rothe
<email@hidden<mailto:email@hidden>> wrote:
But how does EOF differ the objects? They come from different tables (but with
the same name, only the owners differ). The owner I would intercept and change
in the SQL code. Can EOF track this without a model? Also the primary keys
could overlap, because the "slaves" use its own sequence objects, which all
start at 1.
Unless Chuck chimes in with some serious esoterica, I cannot imagine how you’d
get this to work. No, EOF won’t be able to track that without a model. And even
if you could somehow trick it into using a union of several tables, then, and I
think you know this, they’re not really going to function as primary keys if
they can possibly collide.
At the moment I havent't found a delegate for the SQL injection, so I cannot
test it :-(
I don’t think it’s going to help. I just can’t see how EOF can be the solution
to this problem.
--
Paul Hoadley
https://logicsquad.net/
https://www.linkedin.com/company/logic-squad/
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