OLAP - Surrogate key

Surrogate keys can be used to join a dimension table to a fact table in a star schema database.

A surrogate key is a unique identifier for an entity or object in a database that's used when natural keys are not available.

Surrogate keys are  system generated, so it's not possible to create or store a duplicate value.

Dimension Tables 

Fact Tables 

Dimension Tables and Fact Tables are inter-related in 2 ways--

1. Star Schema.

2. Snowflake Schema.

OLAP Cube is a multi-dimensional data..

Four types of analytical operations in OLAP are:-

1. Roll-up  --             Summarize the data / Summation
2. Drill-down -         Reverse of roll-up / Detail view
3. Slice and dice -     Project and Select
4. Pivot (rotate) -       Re-orient the cube./ Transpose