[dtp-dev] about the DTP model change proposal for Catalog

[Hemant S Kolwalkar <hskolwal@xxxxxxxxxx>]

Agreed that DTP 0.9 does not allow saving
models to workspace. But there are
existing projects & commercial products
based on WTP and which allow the saving 
of models to workspace. Facilitating
migration effort will provide incentive 
to these projects/products to move on
from WTP to DTP at the earliest. 

Not all use-cases can be addressed through
model regeneration by re-connecting to
the database. There could be pre-existing
design time models in the workspace or 
in a repository. The migration effort
I mentioned includes the effort needed to write
and test a script to migrate these existing
models.

It is also important we consider how
we will support/represent in the database explorer
those databases which do not support
the concept of a catalog. This also affects the 
migration of existing model resource,
which would not have catalog data persisted. 

To address that, the most simplistis
solution would be a model change as follows:

Database ------  Schema ----- Table
|        
       |
|        
       |
Catalog ------------

At runtime, we can use the metadata
available in vendor docs to determing if a specific
vendor/version supports catalogs.

This solution would not only mitigate
the churn in the catalog loader code mentioned before
but would also address the model resource
migration issue.

thanks,

 - Hemant