Thursday, July 17, 2014

What are the types of database schema?

They are 3 types of database schema they are

  • Star
  • Snowflake
  • Starflake
Star schema:
In star schema fact table will be directly linked with all dimension tables. The star schema’s dimensions are denormalized with each dimension being represented by a single table. In a star schema a central fact table connects a number of individual dimension tables.
The snowflake schema is an extension of the star schema, where each point of the star explodes into more points. In a star schema, each dimension is represented by a single dimensional table, whereas in a snowflake schema, that dimensional table is normalized into multiple lookup tables, each representing a level in the dimensional hierarchy. In snow flake schema fact table will be linked directly as well as there will be some intermediate dimension tables between fact and dimension tables.
Star flake:
A hybrid structure that contains a mixture of star(denormalized) and snowflake(normalized) schema’s.

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