Star Schema Vs. Snowflake Schema Data Model | Power BI || Belayet Hossain
Belayet Hossain
Data Analyst @ZnZ ?Transforming Data into Insight that Drive Decision
The ???????? ???????????? and ?????????????????? ???????????? are two common data modeling techniques used in data warehousing
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?? The Star Schema is the simpler of the two.
??At its core, there’s a ?????????????? ???????? ?????????? This table contains quantitative data, like sales amounts or transaction counts.
??Surrounding the fact table are ?????????????????? ????????????. These tables hold descriptive data, like dates, product names, or customer details. Each dimension table is directly linked to the fact table.
??This leads to a "??????????" shape when you visualize the relationships between tables.
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????????????????????: Easy to understand and navigate since each dimension is directly linked to the fact table.
??????????????????????: Queries are generally faster because there are fewer joins (connections) between tables.
??????????????: It's straightforward to visualize the relationships between data.
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?? The Snowflake Schema is a more complex version of the Star Schema.
?? In addition to the central fact table, some dimension tables are ????????????????????. This means a dimension table might link to other smaller tables.
?? This leads to a ""??????????????????" shape when you visualize the relationships between tables.
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??????????????????????????: Reduces data redundancy by splitting data into multiple related tables.
???????? ??????????????????: Easier to maintain consistency and avoid duplication.
???????????????? ?????? ???????? ??????????????:
Imagine a sales data model:
???????? ??????????: Sales (with columns like ????????????, ??????????????, ????????????????????, ????????????).
?????????????????? ????????????:
Date (with columns like ??????????????, ????????, ?????????, ??????).
Product (with columns like ????????????????????, ??????????????????????, ????????????????).
Customer (with columns like ??????????????????????, ????????, ????????????).
???????????? ?????? ???? ?????? ???? ?????????? ?????
???????? ????????????: Best for most scenarios in Power BI because it’s easier to build, understand, and optimize for performance.
?????????????????? ????????????: Useful if you need to minimize redundancy or if your data naturally fits this structure. However, it requires more careful management of relationships and might complicate the model.
For new learners, start with the Star Schema to get comfortable with data modeling concepts, and then explore the Snowflake Schema as you gain more experience.