IT Professionals

[ramdas2005]

Ramdas

That's great stuff, I am actually working as SQL server / BI Developer, Primarily on SSIS , SSRS on 2008.

Have you got experience in Datawarehouse development, If so can you pls briefly explain the procedure of creating a datawarehouse? Like for Relational Database , you would normalise the data, come up with enitities, then draw up an entity relation ship diagram, then from that you would create the tables, Pk, FK, views, ...etc

I know in Datawarehouse, it is de-normalised data, and you have fact tables/dimensional tables..etc. Can you briefly explain them to me pls

thanks

Hi Paramashivan,
A datawarehouse/data mart contain fact and dimension tables. I am attaching couple of documents which explains fact and dimension tables. The document has sample fact and dimension tables. It also has an image describing Fact and Dimension table relationship. This should give you a good starting point.

Fact and dimension tables are usually populated through Stored procedures/SSIS packages with the source data coming form OLTP relational systems. The SP's and SSIS denormalise the data and populate the fact and dimension tables. Usually the databases for a datawarehouse would be on a different server. The SSIS package would grab data from different source tables in OLTP transfer it to staging tables on datawarehouse database. From the satging tables Stored procedures would transform the data into denormalise form and load them into fact and dimension tables.

Fact Table:
A key characteristic of a fact table is that it contains numerical data (facts) that can be summarized to provide information about the history of the operation of the organization. Each fact table also includes a multipart index that contains as foreign keys the primary keys of related dimension tables, which contain the attributes of the fact records.

Also if you could give me you e-mail id we can correspond better for explanation of concepts.

On a lighter note : Rajini fan / kamal fan/?