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Hey Guys,
I am newbie to QlikView. I had some knowledge regarding data warehousing. Please correct me if I am wrong. Star schema is the simplest style of data warehouse schema. It is said that it is not necessary to have a data warehouse in QlikView, but if there is a star schema in QlikView, there is a data warehouse, isn't it?
Many thanks and regards,
Myr
Hi,
With Qlikview you can do part of ETL transformation, It will not replace ETL.
Have a look at attached document for more info on modelling.
Its suggested to build star schema but Qlik will also support snowflake without any issue.
Its all about performance you choose model. Sometimes you cannot really build star schema.
Regards
ASHFAQ
Star Schema is just a Schema that is popular among Data Warehouses because it allows relational databases to emulate the analytical functionality of a Multi Dimensional Database which is used by OLAP applications such as TM1.
Hi Myr,
Star Schema and Data Warehouse are not synonyms.
Qlikview may replace a data warehouse to some extent, but not in all cases and not entirely IMHO.
For data modelling practices in QV have a look at http://community.qlik.com/docs/DOC-4556
Best of luck
Stefan
Thank you for the responses from you guys!
So Stefan, are there any elaborate explanation regarding to what extent QlikView have replaced a data warehouse?
or in general, where lie the differences between a data warehouse and QlikVIew?
Oversimplified:
Data Warehouse = Concept (read up on books and posts by Bill Inmon or Ralph Kimball)
Qlikview = Software
You can create a simple Data Warehouse using Qlikview mainly with limitations on (complex) ETL.
Example: We have done away with SAP BW for our financial reporting and have moved to getting data from our SAP locations directly from SAP, integrating them with data from our non-SAP locations delivered via Excel. We store the consolidated data (incidentally in a star schema) as Qlikview Data Files (QVDs) and present the data via Qlikview.
Best of luck!
Stefan
Just want to point out that you can't store a data model in a QVD. A QVD file can only store a single table. If you want to share a Data Model you have to use a Binary Load.
Michael, I think what Stefan is referring to is a series of QVD's that "reveal" their star-schema association when loaded together into the same .QVW.
For example, if you had a star-schema associated series of QVD's stored under the directory \SAP_STAR and then loaded the script with
LOAD * FROM SAP_STAR\*.QVD (qvd);
The star-schema will reveal in the same way as if you were performing a binary-load against a pre-loaded .QVW.