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Categories >> Software >> Data Warehouse >> Informatica
 
 


 

 
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Question
What are slowly changing dimensions?
 Question Submitted By :: Informatica
I also faced this Question!!     Answer Posted By  
 
Answer
# 1
Slowly Changing Dimensions:(SCD)
Over period of time, the value /data associated with
dimensions may change. To track the changes we record the
changes as per the requirement.
There are three types of SCD
SCD 1:No history is maintained. As and when data comes, the
data is entered.
SCD 2: History is maintained
SCD 3: Partial History is maintained.
We maintain history for some columns but not for all.
For example,I have 3 records in a dimension
I have made 1 insert and 1 update. Then if the requirement
is that dimension is to be maintained
In SCD 1 Then
Total number of records is 4 records(1 insert & 1 update)
In SCD 2 Then
Total number of records is 5 records(1 insert & 1 update)
In SCD 3 Then
Total number of records is 4 records(1 insert & 1 update)
NOTE:
History means the slight change in the data stored and
incoming data but it doesn't means years of data.
 
Is This Answer Correct ?    34 Yes 4 No
Sri Ram
 
Answer
# 2
DIMENSIONS ARE CLASSIFIED INTO THREE TYPES
SCD TYPE-1 (MAINTAIN CURRENT DATA)
SCD TYPE-2 (MAINTAIN CURRENT DATA+FULL HISTORY OF CHANGES)
SCD TYPE-3 (MAINTAIN CURRENT DATA+ONE TIME HISTORY)
 
Is This Answer Correct ?    25 Yes 2 No
Sandeep.t Nizamabad
 
 
 
Answer
# 3
scds are three types.
type1:it stores the current data.

type2:it stores the full historical data.

type3:it stores the current and previous data in the target...
 
Is This Answer Correct ?    10 Yes 0 No
Anitha
 
Answer
# 4
SCD, is a technique used to store the historical value of
dimension attributes.

The values of dimensional attributes change as time goes by.
When these attribute values change, you can overwrite the
old values with the new ones, or you can
preserve the old value.

There are two methods of preserving the old attribute
values: you can store the old values as rows, or you can
store them as columns

three types of SCD:
SCD type 1 overwrites the old values of the attributes so
the old values are not kept.
Ex: In product dimension,we will use SCD type 1, meaning we
will overwrite the old attribute values.

SCD type 2 keeps the old values by creating a new row for
each change.
SCD type 3 keeps the old values by putting them in another
column
 
Is This Answer Correct ?    0 Yes 1 No
Chaitanya
 
Answer
# 5
there are three types SCD:
type-1: in this we can over write original recourd with new
record
type-2: we can create new record
type-3: we can create new attribute
regards,
ande
 
Is This Answer Correct ?    9 Yes 23 No
Ande
 

 
 
 
Other Informatica Interview Questions
 
  Question Asked @ Answers
 
What are the circumstances that infromatica server results an unreciverable session?   1
if i have a file having record sal=10000,and when use router with two groups having condition sal>5000 in one group,sal>7000 in other group.and if two groups connected to two targets.in which target sal=10000 will go? L&T 7
What is up date strategy and what are the options for update strategy?   2
How can you complete unrcoverable sessions?   1
Can we schedule a workflow(not a session) to run after completition of another workflow? Can we make a workflow depend on completition of another one? GE 2
if the column name in sql override is diff from the column name in source qualifier,what is the impact? TCS 4
my table contain duplicate Records i wanna load uniq records to my table . i have to pass the uniq records through filter t/r how? ACS 3
daily how much amount of data send to production? HSBC 4
Why the UNION TRANSFERMATION is an Active TRANSFERMATION Emphasis 6
What is ThroughPut in Informatica, How it works, Where I can find this option to check ? CTS 5
what is parameter file? Cap-Gemini 1
When will u go for (which means situation) Connected Lookup and Connected Lookup? Pls explain with an example?   3
 
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