Data Warehouse Concepts

Data Warehouse – 

A data warehouse is a subject oriented integrated time variant and nonvolatile collection of data in support of management decision-making process.

Data Warehousing – 

Data warehousing is the process of constructing and using the data warehouse. The major processes involved are data cleaning, data integration, and data consolidation.

Data Mart –

A data mart is the subset of a data warehouse that’s of value to a specific group of users and catering to a specific subject area of the business.

Data Cube –

A data cube allows data to be modeled and viewed in multiple dimensions. it’s defined by dimensions and facts.


Dimensions are the perspectives or entities with respect to which an organization wants to keep records. for example time, item, product, location etc are the dimensions of sales.

Facts – 

Facts are numeric measures. they are the quantities by which we want to analyze the relationship between dimensions. The quantity of sales, Sales Amount etc.

Start Schema –

The most common modeling paradigm for a data warehouse, in which the model contains a large central fact table and all dimension tables are directly linked to the fact table.

Snowflake Schema –

The snowflake schema is a variant of the star schema model where some dimension table is normalized, thereby splitting the data into additional dimension tables.

Fact Constellation –

A collection of stars in which multiple fact tables share same dimension tables.


A sequence of mappings from a set of low-level concepts to higher level more general concepts. Day >> Week >> month >> quarter >> Year


The roll-up operation performs aggregation on a data cube, either by climbing up a dimension hierarchy or dimension reduction.

Drill Down-

The reverse of roll-up. it navigates from less detailed data to more detailed data.


The slice operation performs a selection on one dimension of the given cube, resulting in a subcube.


The dice operation defines a subcube by performing a selection on two or more dimensions.


Pivot is a visualization operation that rotates the data axes in views to provide an alternate data presentation.

Drill through- 

Navigating to the detailed data from the bottom levels.