Relational/Dimensional/Object databases

[#1]

Hi

I am reading about Relational and Object databases, and in this context I would guess that dimensional design is still a part of the relational approach, but where dimensional is focused on OLAP and not OLTP? That is why QlikView care less about NF?   

Edit: I switched OLTP/OLAP around, so it makes more sense now.

[hic]

QlikView doesn't care about normalization forms, because it is not necessary for the evaluation. If a field exists in two tables, QlikView will link them. And that's it. Normalization form, referential integrity, primary keys and many-to-one are concepts that don't matter. See more on http://community.qlik.com/blogs/qlikviewdesignblog/2013/07/15/logical-inference-and-aggregations

About OLTP and OLAP: My experience is that it is in OLAP that the word "Dimension" is used - not in OLTP. In OLTP the term is usually "Master tables". Anyway, in QlikView the word is used in the data model for the tables that surround the fact table, and in charts to describe the Group-By symbols.

HIC

[#3]

Thx, I did mean that QlikView is OLAP, sorry. I edited my first post, so it makes sense.

Concerning many-to-one etc. it must take care of it behind the scene?  

[hic]

When you create your data model, you should of course think about primary keys and many-to-one. Doing so, will help you create a correct data model. But it doesn't affect how QlikView evaluates the data model.

HIC

[#5]

BTW: Most GIS do the combination "ORDBMS" (object/relational), perhaps that would happen to QlikView too.

[#6]

hmm, QlikView is also object?

[rbecher]

You can probably access object databases if they do an object-relational-mapping in the ODBC or JDBC driver. But QlikView itself is relational..

Btw. you can have also a relational OLAP database (called ROLAP) where a dimensional star schema with dimension and facts (similar to OLAP system) is build on relational tables. This would be a good source for QlikView.

- Ralf

[#8]

ok, thx. So that we work with "objects" in the sense of charts etc., has nothing to do with (object) databases?

[rbecher]

No..

[#10]

HIC: "... Anyway, in QlikView the word is used in the data model for the tables that surround the fact table, and in charts to describe the Group-By symbols."

How is the link here. Do you always plan measures and dim. first, and you plan the database design from that? So you migth need to change the whole databasedesign later on?