Interested to Buy Any Domain ? << Click Here >> for more details...
What is a surrogate key?Why we use it in a mapping?Pl give
an example.
- 4 Answers
- 12234 Views
- PCS, I also Faced
- E-Mail Answers
Answers were Sorted based on User's Feedback
Answer / saradhi
surrogate key is used to avoid the critical column.critical
column means the column which makes the analysation or data
wrong for example assume one customer table
cust_id(p.k) cust_name amount loc
1 jones 1000 hyd
he purchase the product in hyd by 1000/- if he again
purchase by 2000/- in pune not in hyd.then we have to
create another record in that table with same cust_id but
here cust_id is having primary key so we are unable to
create a new record for suppose if u update the record u
got the wrong information as
1 jones 3000 pune
so eliminating this we are maintian the another column like
cust_no as surrogate key (unique value)and removes p.k in
cust_id.surrogate key is like an index.
| Is This Answer Correct ? | 12 Yes | 1 No |
surrogate key is a System generated Key ( Artificial
key ),Every join between dimension tables and fact tables
in a data warehouse environment should be based on
surrogate keys, not natural keys.
There are still more reasons to use surrogate keys. One of
the most important is the need to encode uncertain
knowledge. You may need to supply a customer key to
represent a transaction, but perhaps you donýt know for
certain who the customer is. This would be a common
occurrence in a retail situation where cash transactions
are anonymous, like most grocery stores.
What is the customer key for the anonymous customer?
Perhaps you have introduced a special key that stands for
this anonymous customer. This is politely referred
to as a "hack."
| Is This Answer Correct ? | 6 Yes | 1 No |
Answer / venkadesh
IT IS UNIQUE KEY AND ITS USED FOR COMPARING THE EMPLOYEE DETAILS
| Is This Answer Correct ? | 0 Yes | 5 No |
what is the max/min size allocated for caches.whether index or datacache in any of the transformations like Joiner or Aggregator.bcoz it is set to Auto by default which means we need not to allocate no of bytes or MB.so what is the use of these properties.please let me know about the caches. Thnaks in advance Sai Ram
What is deployment group?
What does update strategy mean, and what are the different option of it?
What r the type of indexes u generally used in informatica?
How can you use an Oracle sequences in Informatica? You have an Informatica sequence generator transformation also. Which one is better to use?
My source data like... Empid Name 10 chandra 10 sekhar I am expecting result is Empid Ename 10 Chandrasekhar How can we solve this prob?
1 lac of flat fles in source how to load target at a time?
What is the difference between normal and bulk loading? Which one is recommended?
How will the document be delivered to me?
What is mapplet and a reusable transformation?
how to load the data in fact table.. using look up transformation how to view the second record. usally look up shows matching record for only one value. if i have same value its not displaying. ex: problem i faced. i have total, student no and name in table student i used aggregation transformation to display max(total). i have two same max values in total. when i look up the student name and no for this max(total), its showing only one name and no, its leaving the second one. how to rectify it. plz tel me step by step or clearly.
in which situations do u go for starflake schema ?
Teradata 
