Re: Criteria for handoff from development

You're getting lots of good replies to this Dennis.

One thing I wanted to mention that I had seen yet:

A data architect is going to give you a data model.

This does not necessarily resemble the logical data model or the database design.

When handed a model to implement as a database, there is likely yet a lot of work today. The bigger and more complex the model, the more the database may differ from it.

What is on the model is entities, attributes and relations.

This may not be a 1 to 1 translation to tables, and is actually not likely to be.

A model will contain UID's or Unique Identifiers. Many DBA's
( myself included ) will NOT use these for Primary Keys. Add
your own Primary Keys and use the UID's as Unique Keys.

It will save you a lot of work later when the business rules change
( they *always* change ) as long as you don't use the UK's in
FK relations. Just use PK's for those.

As for business rules, the data architect will likely map those out in some form, but the won't show up on the ERD. Even rules that can be expressed in an ERD need to be defined somewhere else, even if it's just MS Word.

As for those BR that can't be defined in the ERD, where will they reside? In a middle tier? Triggers and packages?

Or in the ( shudder ) application code?

A data model is a *long* way from a working database, so there are a lot of places for you to exercise your discretion as a DBA.

Jared

                                                                                       
                              
                    DENNIS WILLIAMS                                                    
                              
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Can anyone provide some criteria of what you look for when a data model is handed off from production? We are starting a large development project and I lobbied management to hire a data architect. As they have talked to these people, they are getting statements such as "and then the DBA will check out
the data model to make sure there won't be any performance problems". I am concerned about what will be expected of me and wondered how other DBAs handle this situation. What do you look for in a model in terms of making sure the performance will be good? I said that I could look at the queries that would be run to see how many tables would need to be joined to retrieve
the data, but the manager replied that a good DBA wouldn't need to see the queries, should just be able to look at the model. Up until this point, our client-server design tools have tended to protect the developers from doing dumb stuff, but now in the Java world some of those safeguards.

Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com

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