In my October Computerworld column, I tried to explain some of the reasons why I don’t think the pure Relational Model should be as absolutely dominant as its most fervent proponents assert.
The key points were:
1. Logical and physical modeling will never be completely separable.
2. “True relational” DBMSs are very unlikely ever to be practically useful, except perhaps in narrow niches.
3. Enterprises don’t fully control their data models.
4. Duplicated data is not inherently bad.
5. Saying that the relational model (RM) is based on mathematics proves almost nothing.
6. IT isn’t just concerned with facts.
For details see the link above.
And while I’m at it, here’s a link to my September Computerworld column, on three life-and-death apps that won’t get built with a relational architecture.