Data Warehousing Concepts : Fact Tables

In data warehousing fact table or measure table is biggest table which contains numerical facts or measures. In star schema or snow flake schema it’s the canter table and surrounded by dimension table. Ideally fact tables should store additive facts which can be summarized across dimensions. However, sometimes degenerate dimensions are also stored in fact [...]

What Is Surrogate Key

In data warehouse environment each dimension table should have primary key which uniquely identifies dimension record. We can use natural keys or business keys as a primary key in dimension table however these keys are not recommended to be used as primary key in dimension table due to following reasons. 1. These keys are generally [...]

Bill Inmon vs Ralph Kimball

If you are working in data warehousing project or going to work on data warehouse project, you will often hear these two names and differences in their methodologies towards data warehousing. These two people are the guru’s of data warehousing methodologies and they have different methodologies towards data warehousing. Lets understand the basic difference between [...]

An Intrduction to Data Warehousing & Related Topics

This article gives a brief introduction to data warehouse and business intelligence for a beginner who wants to understand the concepts and its usage. Data Warehouse is a central repository of data stored in a specially modeled schema (mostly dimensional model) which can be accessed using reporting & analysis tools or SQL for data analysis [...]

Good Books to Understand Concept of BigData

What is BigData? Do i have so called BigData problem or I just have normal data which can be analyzed using traditional BI tools. What are the typical problems of BigData and solutions? Which tools i should be using to analyze BIgData. To answer all above question one needs to understand the basics of BigData. [...]

Data Warehouse Project Life Cycle

Executing a data warehousing project is not different than executing any other development project. However one needs to be very structured and methodical in order to execute a project and making it a big success. Data warehouse project manager needs to be technical and business person who understand technical details along with organizations business. Following [...]

What is Metadata?

Metadata is the information or data in Data Warehouse that is not exactly the data itself but its data about the data. In a broader way you can view Metadata as an encyclopedia of the data warehouse. Metadata in Data Warehouse contains information about the various Database Objects used in Data Warehouse, Systems Tables, Catalog [...]

Slowly Changing Dimension

Have you encountered a situating where your main customers are mainly college going students and they are your main customers and you have seen substantial revenue drops when these students pass out and move to new place for jobs or higher studies. Well even a blind can say ,  as the company do not have [...]

Dimensional Data Model

To design a datawarehouse one need to design dimensional data model. The dimensional data model provides a method for making databases simple and understandable by denormalizing it and removing extra join which are generally required to fetch the data. In general you can imagine dimensional database as a cube of three or more dimensions using [...]


The Data Warehouse (OLAP) is  different from the operational database(OLTP) which is used and maintained for day-to-day operational systems. Following are the few differences: OLTP application oriented detailed accurate, as of the moment of access serves the clerical community can be updated requirements for processing understood before initial development compatible with the Software Development Life [...]

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