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Categories >> Software >> Data Warehouse >> Informatica
 
 


 

 
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Question
What are the different types of schemas?
 Question Submitted By :: Informatica
I also faced this Question!!     Answer Posted By  
 
Answer
# 1
two types of schemas r there: Star schema and snow flake
Schema: in Snow flake schema normalozation is promoted
where as in star schema denormalization is promoted. incase
of snowflake schema DB size will be saved but no of joins
will be increased and poor performance compare with star
schema
regards,
ande
 
Is This Answer Correct ?    67 Yes 26 No
Ande
 
Answer
# 2
3types of schems:
Star Schema (As above)
Snow Flake Schema (As above)
Galaxy or Integrated or Fact Constellation Schema ( By
which, a dimensional table is shared by one or more Fact
tables )

Good Luck.
 
Is This Answer Correct ?    34 Yes 11 No
Kalyan
 
 
 
Answer
# 3
There are 3 types of Schemas,
1.Star Schema
2.Snowflake Schema
3.Galaxy/Integrated/Hybride/Consalation Schemas
1)Star Schema-It is defined as the fact table is centrally located,surrounded by dimension tables is called star schema.In that dimension tables are denormalized and fact table is normalized.(or)Star schema is defind as two or more fact and two or more dimension tables that are related to foreigh keys.
2)Snowflake Schema-It is defind as the Denormalized Dimensions tables are can be splited into two or more normalized dimensions is called snowflake schema.In that both dimensions and fact tables are normalized.
3)Hybride Schema-It is defind as a dimension table is shared by two or more fact tables.
 
Is This Answer Correct ?    19 Yes 6 No
Mallikarjun
 
Answer
# 4
Schema is structure of information

1.STAR SCHEMA
-------------
Centralized Fact table connect the one or more denormalized data

2.SNOW FLAKE SCHEMA
-------------------

Centralized Fact table connect the one or more normalized data

3.STAR FLAKE SCHEMA
-------------------

One or more centralized fact table connect the single denormolized data
 
Is This Answer Correct ?    24 Yes 19 No
Giri
 
Answer
# 5
There are 3 types of Schemas :
1. Star Schema -The star schema architecture is the
simplest data warehouse schema. It is called a star schema
because the diagram resembles a star, with points radiating
from a center. The center of the star consists of fact
table and the points of the star are the dimension tables.
Usually the fact tables in a star schema are in third
normal form(3NF) whereas dimensional tables are de-
normalized. Despite the fact that the star schema is the
simplest architecture

2. Snow Flake Schema - The snowflake schema architecture is
a more complex variation of the star schema used in a data
warehouse, because the tables which describe the dimensions
are normalized

3. Fact Constallation Schema : For each star schema it is
possible to construct fact constellation schema(for example
by splitting the original star schema into more star
schemes each of them describes facts on another level of
dimension hierarchies). The fact constellation architecture
contains multiple fact tables that share many dimension
tables.
 
Is This Answer Correct ?    6 Yes 1 No
Thirumalai
 
Answer
# 6
Very nice page I must say.

Mainly Data warehouse has three type of schemas available.

1. Star Schema

2. Snow Flake Schema

3. Fact Constellation Schema or Galaxy Schema

It was really hard time for me to get to know exactly how this all schema works and what is the main differences between these schema.

I searched a lot on web and got one detailed answer in below link. May be this can also help you guys to understand.

http://www.aajsearch.com/142/what-are-the-different-schema-in-data-warehousing
 
Is This Answer Correct ?    1 Yes 0 No
Kick
 
Answer
# 7
star schema
snow flae schema
hybrid schema
multistar schema
 
Is This Answer Correct ?    0 Yes 0 No
Gopi
 
Answer
# 8
There are two types of shemas
1 star schema , 2 snowflake schema
star schema : a fact table related to tha dimension tables
like in the fact table it contain refernce keys of
dimension tables. and dimension tables dont related to the
other parent table . it view like a star so its call star
schema. if this use to avoid more joins
snowflake schema: a dimenion table with related to the it
hirerchi tables. like time dimensin table year dimension
table, month month dimension table, week dimension table
it view like snowflake
 
Is This Answer Correct ?    21 Yes 22 No
Chowdary
 
Answer
# 9
schems are two types one is star schema and another one is
snow flake schema
 
Is This Answer Correct ?    3 Yes 9 No
Ramesh
 
Answer
# 10
three types of schemas are availble.Star schema,star flake
schema & snow flake schema.

Star schema:It is highly denormalised,so we can retrieve
the data very fast.

Star flake schema:Only one dimension contain one level of
hierachy key.

Snow flake schema:It is highly normalised,so retrievel of
data is slow.
 
Is This Answer Correct ?    32 Yes 39 No
Vignesh Muralidharan
 

 
 
 
Other Informatica Interview Questions
 
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what is degenerated dimension? IBM 1
How to load time dimension? Ford 1
if i have one mapping and we already tuned that mapping for performance,everything is fine and loading will take 1 hr,so without doing any change in mapping how could we reduce the loading time from 1hr to 1/2 hr. Wipro 4
What is 'PowerCenter Pushdown Optimization Option' in INFORMATICA ?   5
what is flat file override? Cap-Gemini 1
what is update strategy transformation ? TCS 7
1 2 3 * 4 5 6 * 7 8 9 how to load records between two stars(*), Cap-Gemini 9
how to join the two flatfiles using the joiner t/r if there is no matching port? Cegedim 5
How can i explain my project architecture in interview..? in Igate asked me tell me your project flow from source to target..? iGate 1
What are limitations of joiner transformation? Exilant 2
I HAVE 10 records in source. I want to store i record in target 1, second record in target 2, third record in target 3, 4 th record again in target 11, 5th again in target 2, 6th again in target3 etc.... how it is possible? Syntel 5
Hi 2 every one. i dont have real time experience, and please suggest me for following questions. a) we get the source data from what type of source systems? b) In banking domain project what are the FACT & DIMENTION tables please list out them? c) please write some colomn names in a table? Please reply for aboue questions?..... Thanks in advance. AMDOC 1
 
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