Re: Normalization and DBMS

Em Tue, 11 May 2004 20:10:10 -0500, Dawn M. Wolthuis escreveu:

> it seems to have a direct correlation to the flexibility of a
> system to withstand years of requirements changes

        Quite to the contrary. With nested tables, the only way to ever reach the subtable is thru the supertable.

        On the other hand if you only have relations, the data will always be there...

> For example, if people used to have an e-mail address and now they
> have several, sometimes absolutely NOTHING has to change in the
> entire application other than to change the metadata for the field
> to describe it as permitting multiples.

 CREATE	TABLE
	email

> However, when working with SQL-DBMS's, it seems that developers use
> clever methods to keep from building new tables when cardinality
> changes

        This is a tools issue, not a DBMS one. If the tools request codification changes, so be it. It is a low-level tool.

        For many good-quality screen painters and the like nothing will be required.

        You seem to be thinking about a 4GL. Aren't you one of the Pick guys?

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