topic Re: Relational/Dimensional/Object databases in QlikView

Relational/Dimensional/Object databases

Sun, 08 Jun 2014 20:27:29 GMT

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.

Re: Relational/Dimensional/Object databases

hic — Mon, 09 Jun 2014 01:10:01 GMT

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

Re: Relational/Dimensional/Object databases

Mon, 09 Jun 2014 11:37:44 GMT

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?

Re: Relational/Dimensional/Object databases

hic — Mon, 09 Jun 2014 11:41:49 GMT

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

Re: Relational/Dimensional/Object databases

Mon, 09 Jun 2014 12:03:30 GMT

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

Re: Relational/Dimensional/Object databases

Tue, 10 Jun 2014 15:43:56 GMT

hmm, QlikView is also object?

Re: Relational/Dimensional/Object databases

rbecher — Tue, 10 Jun 2014 16:05:51 GMT

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

Re: Relational/Dimensional/Object databases

Wed, 11 Jun 2014 15:44:13 GMT

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

Re: Relational/Dimensional/Object databases

rbecher — Wed, 11 Jun 2014 15:51:19 GMT

No..

Re: Relational/Dimensional/Object databases

Mon, 16 Jun 2014 13:00:15 GMT

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?

Re: Relational/Dimensional/Object databases

hic — Mon, 16 Jun 2014 13:19:05 GMT

When I make applications, I look at data and make a data model from that. Then I listen to the user and tweak the data model.

In other words: The data model is really decided from data and not from the user wanting to see this or that in a pivot table. A good, logical data model will meet most (or all) user demands without any changes.

HIC

Re: Relational/Dimensional/Object databases

Tue, 17 Jun 2014 21:43:32 GMT

Thx, that is the way I have been thinking so far.

But then I dont understand all this hype with fact/dimension database design in a star design, why is that so important? I dont find that "logical" to work with, I find thematic tables side by side, perceptual easier too figure out and work with.