Mumbai University > Information Technology > Sem 5 > Advanced Database Management System

Marks: 5M

Year: Dec 2014

• The snowflake schema represents a dimensional model which is also composed of a central fact table and a set of constituent dimension tables which are further normalized into sub-dimension tables.
• In a snowflake schema implementation, Warehouse Builder uses more than one table or view to store the dimension data.
• Separate database tables or views store data pertaining to each level in the dimension.

• Some dimension tables in the Snowflake schema are normalized.
• The normalization splits up the data into additional tables.
• Unlike Star schema, the dimensions table in a snowflake schema are normalized. For example, the item dimension table in star schema is
• normalized and split into two dimension tables, namely item and supplier table.
• Now the item dimension table contains the attributes item_key, item_name, type, brand, and supplier-key.
• The supplier key is linked to the supplier dimension table. The supplier dimension table contains the attributes supplier_key and supplier_type.
• Due to normalization in the Snowflake schema, the redundancy is reduced and therefore, it becomes easy to maintain and the save storage space.