What's Fact & Dimension tables?

qWhat is Dimension Table?

vDimension contains descriptive attributes(data) about a subject.

vThe table which describe the dimension called Dimension table.

vA dimension table has a primary key column that uniquely identifies each dimension record (row). 

vE,g: ‘Company’ is a subject Employee, Department and date is Object(dimension tables) .ID,Name,Dept Nm, joining Dt , Release Dt are attributes(columns).

qWhat is Fact Table?

vFact is something that is measurable. It contains only numeric value which can be aggregated.

vA fact table contains information about KPIs and measure.

vKPI stands for Key Performance Indicator which is nothing but Dimension tables Primary Key

vMeasures are data elements that can be summed, averaged, or mathematically manipulated

 Example:

•Above customer ,store ,product and time tables are dimension tables which contain attributes

•Purchase is the fact table which contains all PKs of dimension tables and price and tax column which are measures.