> For the complete documentation index, see [llms.txt](https://gchandra.gitbook.io/data-warehousing/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gchandra.gitbook.io/data-warehousing/fundamentals/8-steps-to-design-a-data-warehouse/data-modeling.md).

# Data Modeling

* Data Modeling is a process to visualize the data warehouse.
* It helps to set standards in naming conventions, creating relationships between datasets, and establishing compliance and security.
* Most Complex phase in data warehouse design.
* Recollect Top - Down vs. Bottom - Up that decision plays a vital role.
* Data Modelling typically starts at the data mart level and then branches out to the data warehouse.
* Three popular data models for data warehouses
  * Star Schema
  * Galaxy Schema
  * Snowflake Schema