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From Thomas Dudziak <tom...@gmail.com>
Subject Re: Package names
Date Sun, 01 May 2005 09:24:51 GMT
> On that same topic, if there are interfaces that we want to expose, and
> implementations of the interfaces that are typically hidden, we need
> factories that can produce the implementation classes. This leads to a
> bootstrap issue: how to instantiate a factory.
> 
> There are several options that we've used to solve the factory
> bootstrap issue, and once we make a decision on the interfaces, the
> factories are the next step toward a solution.
> 
> The solution that we choose will affect the interfaces as well. I'm
> comfortable with a pattern in which the interface for Table for example
> includes a factory method for Column. So once you have solved the top
> level bootstrap issue, you have factories for all the subordinate
> interfaces built into the interfaces themselves.

I'd like to avoid having the element creation in the implementation.
Rather I'd prefer a model factory that can create the 8 model element
types.
For reading a model from a database/XML file, the registration is not
a problem. You simply register the factory at the reader object. For
creating a model manually, you probably don't need a factory anyway
and rather use the model objects themselves.
 
> Another issue I'd like to talk about is the handling of Catalog and
> Schema. It appears that in a Database, you can have Tables that are of
> different catalogs and schema, but when you find a Table in a database,
> you ignore the catalog and schema. Is it possible to have a Database
> with two tables with the same name but different catalogs and schema?
> Or will that result in a name clash?

I don't know off-hand how that is handled (as I said, unit tests are
missing), but I'd like to think that this depends upon the jdbc
driver. For DdlUtils it is no problem that the table name has a dot in
it (i.e. something like a qualified name), but the question is in what
form the jdbc driver returns metadata for databases that support
catalogs/schemas. Which databases support these ?

Tom

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