Re: Multiple clients in single DB
Re: Multiple clients in single DB
- Subject: Re: Multiple clients in single DB
- From: Lachlan Deck <email@hidden>
- Date: Fri, 27 Apr 2007 06:35:43 +1000
Hi Dave,
On 26/04/2007, at 11:33 AM, Dave Elsner wrote:
I have an WO5.3 application I want to deploy to five different
clients, all have the same DB (Oracle) schema but different data. I
would like to use a shared database with a new column in each table
"client" that has the client ID. Then override awakeFromInsertion
for all EOEntities to set the client ID
That's what I've done (though it's done generically in a super class
rather than per entity). Something like:
public void awakeFromInsertion( EOEditingContext ec ) {
super.awakeFromInsertion( ec );
if ( ec instanceof MyEditingContext && hasKey( CLIENT_KEY ) ) {
Client currentClient = ( Client )ec.valueForKey( CLIENT_KEY );
if ( hasReverseRelationship )
addObjectToBothSidesOfRelationshipWithKey( currentClient,
CLIENT_KEY );
else
takeValueForKey( currentClient, CLIENT_KEY );
}
}
and also add to the Application constructor a loop that sets an
EOQualifier on each entity in the model limiting objects to the
current client.
Sure that's one way to do it if you're going to be running them as
separate instances. I'm dealing with this within the same instance(s)
by an additional table ClientDomain (Client <-->> ClientDomain). I've
got some cover methods in my Application class that when needed can
find the relevant object for a request. It stores the result in the
userInfo dictionary of the request so that this only need be fetched
once, if at all - seeing as these objects are pre-fetched in a shared
ec.
public Client clientForRequest( WORequest aRequest ) throws
EOObjectNotAvailableException, EOUtilities.MoreThanOneException;
public ClientDomain clientDomainForRequest( WORequest aRequest )
throws EOObjectNotAvailableException;
I'm then (in a base controller/component) able to have cover methods
for these. e.g.,
public Client myClient() {
return myApplication().clientForRequest( context() );
}
and whenever I need to create data, I create an instance of my
subclass of EOEditingContext which is instantiated with an additional
parameter for the ClientDomain, allowing it to localise as necessary
internally and for the above valueForKey to return the related Client
object.
Questions:
* Is this the correct approach to solve this problem? (i.e not
wanting to update X number of identical DB schemas every-time a
change is made, keeping the data in the one location for reporting)
Perhaps the above helps.
* I tried EOEntity.setRestrictingQualifier but that overrides any
single table inheritance setup in the model. Is there away to merge
two EOQualifiers?
When iterating through each entity, do an EOAndQualifier with any
existing restricting qualifier so that you don't blow it away.
with regards,
--
Lachlan Deck
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