Interested to Buy Any Domain ? << Click Here >> for more details...
When should you use a STAR and when a SNOW-FLAKE schema?
- 6 Answers
- 49579 Views
- Accenture, I also Faced
- E-Mail Answers
Answer Posted / freak.abinitio
Snowflake schema architecture is a more complex variation of a star schema design. The main difference is that dimensional tables in a snowflake schema are normalized, so they have a typical relational database design.
Snowflake schemas are generally used when a dimensional table becomes very big and when a star schema can’t represent the complexity of a data structure. For example if a PRODUCT dimension table contains millions of rows, the use of snowflake schemas should significantly improve performance by moving out some data to other table (with BRANDS for instance).
The problem is that the more normalized the dimension table is, the more complicated SQL joins must be issued to query them. This is because in order for a query to be answered, many tables need to be joined and aggregates generated.
A dimensional modelling technique in which a detail fact table is linked to dimension tables.
The data in data warehouses and data marts is accessed by end-users. The information contained in the data warehouse/data mart must be easy for the end-user to use and access. Denormalized designs are easier for end-users to use than highly normalized designs, however these designs are more difficult to design and maintain.
The Star Schema diagram graphically models the end-user's view (i.e., the denormalized view) of how the information is accessed.
Components of a Star Schema Diagram
The diagram has three main components:
· Fact Table and its contents: metric attributes and the foreign keys necessary to join to the dimension tables,
· Dimension Tables and their contents: reference attributes, hierarchical attributes, and metric attributes. The dimension tables are highly denormalized,
· the lines that link the Dimension Tables to the Fact Table.
| Is This Answer Correct ? | 3 Yes | 2 No |
Post New Answer View All Answers
What is a view as it relates to system modeling?
Explain what is analytical or analytic mean?
Explain what are the methodologies of data warehousing?
What are the types of dimensional modeling?
What is many-to-many dimensional model in datawarehousing ?
What are data validation strategies for data mart validation after loading process?
Explain what are the different methods of loading dimension tables?
I need a good brd and uc template?
Explain dimension table ?
What is data validation strategies for data mart v?
what are the different views that are considered when building an object-oriented software system?
What is the main difference between schema in rdbms and schemas in datawarehouse?
What is the 4 + 1 view model as it relates to system modeling?
What function should we use to display the value entered or selected by a user in response to a prompt?
Explain why fact table is in normal form?
