Data is a crucial part of our life. Whether it is an organization or the individual level, every important task requires data in one or another form. At the senior or high level of management when there is a large depository of data, various concepts and methods are used to manage the same. Star and snowflake schema are two important concepts that are associated with data warehousing or depository.
Star vs Snowflake Schema
The main difference between star and snowflake schema is that in star schema the concept of fact table plays a vital role. It is a database structure that primarily used the table to store and measure the data. It is a top-down model for the database depository that uses more space. The snowflake schema on the other side is an arrangement of data that is preorganized in a table. It is a bottom-up model with a complex and logical design.
Star schema is the organizational structure that is used for monitoring the database. It is used in business intelligence to measure the data. This structure is called the term star because at the center there would be space for the fact table and the other small table are positioned as points of the star. Each star has one single fact table that contains the data that need to be analyzed.
The snowflake schema is the extended form or the structure of the star schema. This database depository model is comprised of a dimension table, fact table, and sub-dimension table. This model or structure is quite difficult to understand as it has a complex design with more foreign keys.
Comparison Table Between Star and Snowflake Schema
|Parameters of Comparison||Star Schema||Snowflake Schema|
|What is it?||Star Schema is an organizational structure in which the information is represented by lookup and fact table and primarily are comprised of dimension and fact table||Snowflake Schema is a structure used in business intelligence that represent the data in a normalized manner|
|Type of Model||It has a top-down model||It has bottom-up model|
|Design||It has a simple design structure||It has a complex design structure|
|Complexity||Star schema is easy to understand with low query complexity||Snowflake schema is difficult to understand with comparatively higher query complexity|
|Foreign Key||It has comparatively less number of foreign keys||It has more number of the foreign keys|
|Disk Space||Star schema use more disk space||Snowflake schema use less disk space|
What is Star Schema?
Star schema is the concept that is majorly used for business intelligence or in other words it plays a significant role in database depository management. It is comprised of the fact and dimensional table that stores a large amount of data that needs to be analyzed or measured. Basically two types of information are stored in the fact table, it includes the numeric value and attribute value related to the dimension. The numeric value is the unique value that does not relate to any data stored in the table while the attribute value is not directly involved in storing the data, they store the value in a foreign key.
The star schema is related to recording information that could be similar and result in duplicated data. It is designed in a simple way with easy data aggregation and integration. This organizational structure provides fast access to the data and makes it easier and convenient to evaluate the business insights. It works effectively with OLAP systems that consequently store data by creating OLAP cubes.
What is Snowflake Schema?
The snowflake schema is the structure that assist in maintaining and analyzing the data. It is comprised of sub-dimension, dimension, and fact table. This bottom-up model normalizes the data effectively by linking one reference table to another. The model resides to that of a snowflake as it contains the fact table at the center and the reference table constitute the branches. Snowflake schema has a complex design and it is a bit difficult to maintain.
Main Differences Between Star and Snowflake Schema
- Star Schema is an organizational structure in which the information is represented by a lookup and fact table and primarily are comprised of dimension and fact table. On the contrary, Snowflake Schema is a structure used in business intelligence that represents the data in a normalized manner.
- Business intelligence uses a various organizational structure for analyzing the data. Star schema is based on the top-down model. While the snowflake schema on the other side is based on the bottom-up model.
- The data stored in various formats constitute the data warehouse. The multidimensional models are designed to derive various queries from the data depository. Star schema has a simple design structure while snowflake schema on the other side has a complex design.
- Every business intelligence model which is designed for database warehouses has some complexity level that varies from one to another. Star schema is easy to understand with low query complexity. While snowflake schema on the other side is difficult to understand with comparatively higher query complexity.
- The star schema is designed in such a way that there would be no link or branching from any dimension table. But in snowflake schema, one branch may associate with another one in one or another way.
Star and snowflake schema has their significance and uses. Each of these multidimensional models is based on some structure in which the information is organized. Star schema is a good option for those who do not have a large database or data warehouse. It facilitates low complex queries in a fast manner. While the snowflake schema is suggested for advanced queries related to the analytics. Although every modern technology has some advantages and disadvantages. The organization selects any of these models that resembles with their requirement and the amount of data they have in their data warehouse.