Mythology I always thought that databases should be denormalized for reading, as it is done for OLAP database design, and not exaggerated much further 3NF for OLTP design. There’s a myth to that effect. In the Relational Database context, I have re-implemented six very large so-called “de-normalised” “databases”; and executed over eighty assignments correcting problems … Read more
A data warehouse is a database with a design that makes analyzing data easier†and faster, often with data from multiple sources. It usually has a dimensional model, meaning fact tables and dimension tables. OLAP is a set of operations that one can do on a data set, such as pivoting, slicing, dicing, drilling. For … Read more
Check out this for more information. From a previous link: Database Used for Online Transactional Processing (OLTP) but can be used for other purposes such as Data Warehousing. This records the data from the user for history. The tables and joins are complex since they are normalized (for RDMS). This is done to reduce redundant … Read more
In Data Warehouse Modeling, a star schema and a snowflake schema consists of Fact and Dimension tables. Fact Table: It contains all the primary keys of the dimension and associated facts or measures(is a property on which calculations can be made) like quantity sold, amount sold and average sales. Dimension Tables: Dimension tables provides descriptive … Read more