Difference Between Star and Snowflake Schema
By BYJU'S Exam Prep
Updated on: September 25th, 2023
The main Difference Between Star Schema and Snowflake Schema that start schema has the simple design whereas the snowflake schema has the complex design. The data warehouse uses various schema or multidimensional models. Both the schema carries the dimension and fact tables.
Difference Between Star Schema and Snowflake Schema PDF
Data warehouse uses different types of schema depending upon the requirements which makes it accurate, consistent and reliable. Here, we will explore the difference between Star Schema and Snowflake Schema in detail along with understanding each in detail.
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Difference Between Star Schema and Snowflake Schema
The main difference between Star Schema and Snowflake Schema is that in Star schema the complexity of the query function is low whereas in the Snowflake schema, it is highly complex. The star and snowflake schema are important for the GATE exam. The table shown below shows the comparison of both the schemas in detail.
Star Schema vs Snowflake Schema
| Star Schema and Snowflake Schema | |
| Star Schema | Snowflake Schema |
| The star schema follows the top-down model. | The snowflake schema |
| The star schema has dimension and fact tables. | The snowflake schema has sub, dimension and fact tables. |
| The space occupied by this is higher. | This schema consumes less space. |
| The time taken by star schema is less. | The time taken by snowflake schema is more. |
| The processes like normalization and denormalization is not used in this. | The processes like normalization and denormalization is preferred and used in this schema. |
| The star schema carries simple design. | The snowflake schema carries complex design. |
What is Star Schema?
Star schema is the basic schema surrounded by the data mart schema and this is the simplest. The star schema is widely used in data warehouses and dimensional data marts. It includes one or more fact tables classifying any number of dimensional tables. This schema is a crucial cause of the snowflake schema. It is also efficient for handling primary queries.
This schema is said to be a star because its physical model resembles the star shape and it has a fact table at the centre of the logical diagram and dimension tables at its borderline representing the star’s points.
What is Snowflake Schema?
The snowflake schema is a kind of star schema. It is a multi-dimensional data model that is an extension of a star schema. In this schema, dimensions exist in a normalized form in multiple related tables. Snowflake structure materialized when the dimensions of a star schema are detailed and decidedly structured, having several levels of relationship, and the child tables have various parent tables.
The snowflake effect affects only the dimension tables and not the fact tables. These schemas are frequently used for business intelligence and reporting in OLAP data warehouses, relational databases and, data marts.
