Interested to Buy Any Domain ? << Click Here >> for more details...
Answer Posted / manoj
When developing a dimensional model, we often encounter miscellaneous flags and indicators. These flags do not logically belong to the core dimension tables.
A junk dimension is grouping of low cardinality flags and indicators. This junk dimension helps in avoiding cluttered design of data warehouse. Provides an easy way to access the dimensions from a single point of entry and improves the performance of sql queries.
Example: For example, assume that there are two dimension tables (gender and marital status). The data of these two tables are shown below:
Code:
Table: Gender
Id Gender_status
----------------
1 Male
2 Female
Table: Marital Status
Id Marital_Status
----------------
1 Single
2 Married
Here both the dimensions have low cardinality flags. This will cause maintenance of two tables and decrease performance of sql queries.
We can combine these two dimensions into a single table by cross joining and can maintain a single dimension table. The result of cross join is shown below:
Code:
id gender mrg_status
--------------------
1 Male Single
2 Male Married
3 Female Single
4 Female Married
This new dimension table is called a junk dimension. This will improve the manageability and improves the sql queries performance.
| Is This Answer Correct ? | 12 Yes | 0 No |
Post New Answer View All Answers
How can we run the graph? How can we schedule the graph in unix?
What are the steps of implementing data warehousing?
What are different deliverables according to phases?
Why should we use data ware housing and how can you extract data for analysis with example?
What are templates in which way it is help full?
Explain Association algorithm in Data mining?
Explain what is fact less fact table? Where you have used it in your project?
Ist the schema that a data warehouse system can implements.
Tell me what is degree of a relation?
What is the difference between Datawarehouse and OLAP?
What is the use of incremental aggregation? Explain me in brief with an example?
Why is dimensional normalization not required?
What is the difference between drill through and masterdetail reports?
What is cubes?
Can we have multiple application.cfm file in an application?
