Re: OO and relation "impedance mismatch"

From: Fredrik Bertilsson <>
Date: 2 Oct 2004 11:39:41 -0700
Message-ID: <>

Troels Arvin <> wrote in message > I think that the impedance mismatch would be less of a problem, if
> 1. RDBMSes got better at useful error reporting,
> which the application layer could easily translate
> into meaningful error messages for the end user.
> That way, a lot of redundant, defensive error avoidance
> code could be torn out of the middle ware/application.
> 2. Relations in RDBMSes were easier to query for
> metainformation: E.g., if it were easier to deduce valid
> values for a column, the application could automatically
> map columns to useful end-user widgets. JDBC and
> similar RDBMS access software already offers some
> metadata information about tables (which I think should
> be used more), but as far as I know, there is no
> easy way to translate a set of CHECK constraints
> into auto-generated data types in the application
> layer. For once, I actually want to praise MySQL:
> MySQL has the ENUM type which is easy to translate
> into a data type with a discrete set of valid
> values. Unfortunately, MySQL's ENUM type is not
> gotcha-free:

But these problems are the same if you use a non-OO language too, right?

/Fredrik Received on Sat Oct 02 2004 - 20:39:41 CEST

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