What is the difference between warehouse key and surrogate key?
- 1 Answers
- 5930 Views
- Accenture, I also Faced
- E-Mail Answers
Answer Posted / jaspreet banga
Surrogate key concept:- Surrogate keys are generated by
system and they identifies unique 'ENTITY'! yes its entity
and not record ,while primary key is used for finding
unique record.
Let me give you a simple classical example for surrogate
key:
On the 1st of January 2002 Employee 'E1' belongs to
Business Unit 'BU1' (that's what would be in your Employee
Dimension). This employee has a turnover allocated to him
on the Business Unit 'BU1' But on the 2nd of June the
Employee 'E1' is muted from Business Unit 'BU1' to Business
Unit 'BU2.' All the new turnover have to belong to the new
Business Unit 'BU2' but the old one should Belong to the
Business Unit 'BU1.'
If you used the natural business key 'E1' for your employee
within your datawarehouse everything would be allocated to
Business Unit 'BU2' even what actualy belongs to 'BU1.'
If you use surrogate keys you could create on the 2nd of
June a new record for the Employee 'E1' in your Employee
Dimension with a new surrogate key.
This way in your fact table you have your old data (before
2nd of June) with the SID of the Employee 'E1' 'BU1.' All
new data (after 2nd of June) would take the SID of the
employee 'E1' 'BU2.'
You could consider Slowly Changing Dimension as an
enlargement of your natural key: natural key of the
Employee was Employee Code 'E1' but for you it becomes
Employee Code Business Unit - 'E1' 'BU1' or 'E1' 'BU2.' But
the difference with the natural key enlargement process is
that you might not have all part of your new key within
your fact table so you might not be able to do the join on
the new enlarge key -> so you need another id.
| Is This Answer Correct ? | 3 Yes | 1 No |
Post New Answer View All Answers
SOURCE DATA IS DISPLAY IN THIS FORMATE IN TARGET . WHAT BUSINESS LOGIC WE CAN APPLY. source table target table ------------ ------------ c1 c2 c3 c1 c2 c3 -- -- -- -- -- -- 1 A J 1 2 B K 2 A 3 C L 3 B J 4 D M 4 C K 5 E N 5 E L F M N
can anyone explain me about retail domain project in informatica?
What the difference is between a database, a data warehouse and a data mart?
What is option by which we can run all the sessions in a batch simultaneously?
-Which expression we can not use in Maplets?, -Can we join(relate) two dimensions in a schema? -Why and where we use 'sorted input' option?
What is the scenario which compels informatica server to reject files?
How to do unit testing in informatica? How to load data in informatica ?
How to elaborate powercenter integration service?
What are the new features of informatica 9.x in developer level?
Define mapping and session?
How do you load more than 1 max sal in each department through informatica or write sql query in oracle?
What is dimensional table? Explain the different dimensions.
What are the performance considerations when working with aggregator transformation?
what is size of u r database?
How many transformations can be used in mapplets.
