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What are slowly changing dimensions
swathirao_829
- Dec 6th, 2008
A Slowly Chaging dimension explains changed data captures over the period of time. There r three types of slowly changing dimensions(SCD).1)Type 1 SCD: It keeps most recent updated values in the targe...
1292033
- Aug 2nd, 2007
The definition of slowly changing dimension is in its name only. The dimension which? changes slowly with time. A customer dimension table represents customer. When creating?a customer, normal assum...
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What is the datatype of the surrgate key
jaggu_mandya
- Jan 11th, 2008
It is a system generated sequence number, an artificial key used in maintaining history.It comes while handling slowly changing dimensions
ankitmohansharma
- Jan 7th, 2008
Hi all, Surrogate key is mostly a sequential number. Although it doesn't has to be. They are system-generated artificial primary key values. Typically, every row would have both a primary key and ...
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What is the need of surrogate key;why primary key not used as surrogate key
bcsandip
- Jul 16th, 2010
In DW, a fact table stores a few Primary keys of the corresponding Dimension tables. It will be always easier to get the desired record from the fact table when query is fired based upon a particular unique column and that is the another reason to introduce surrogate key.
srinuv_11
- Dec 8th, 2006
Datawarehousing depends on the surrogate key not primary key, for suppose if u r taking the product price it will change over the time, but product no. will not change but price will change over...
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Do u need seperate space for Datawarehouse & Data mart
moluguri
- Aug 30th, 2012
I think, we don't need separate space for Data Warehouse and Data Mart. Data Warehouse is a collection of Data Marts. Data Mart is a particular line of business..
Gvkishore
- Jan 16th, 2012
Why so.....Is there any advantage creating the DWH after creating the Datamarts...?
what is the use of Vice versa...? -
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ODS and Staging
What is the difference between ODS and Staging?
prat4all
- May 25th, 2009
ODS keeps the transactional data from where direct reporting is possible. The data in ODS can be partly denormalized.Staging area is the exact replica of the transactional database which acts as a source for datawarehouse processing.
shanavaz
- Nov 1st, 2008
ODS, Operational Data Store is majorly different from Staging in the below aspects: - Existing Records in the System can get updated based on necessary instructions & design. - It can be use...
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opposite is true?
">Difference between Snow flake and Star Schema. What are situations where Snow flake Schema is better than Star Schema to use and when the opposite is true?
justins707
- Jan 11th, 2010
When we refer to Star and Snowflake Schemas, we are talking about a dimensional model for a Data Warehouse or a Datamart. The Star schema model gets it name from the design appearance because th...
Chris
- Mar 29th, 2007
Star Schemas generally contain fact tables with fully denormalised dimension tables connecting directly to the fact table. A snowflake schema is a modification of this approach whereby the dimension t...
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What is the difference between Data modelling and Dimensional modelling?
mri_sonam
- Dec 17th, 2008
When data modeling, we are structuring and organizing data. These data structures are then typically implemented in a database management system. In addition to defining and organizing the data, data ...
Blueash
- Nov 15th, 2008
Modelling data storage optimized for Transactional Processing is Data Modelling.Modelling data storage optimized for Analytical Processing is Dimension Modelling.
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Fact Table
Fact Table is
a) Completely Normalized
b) Partially Normalized
c) Completely De-normalized
d) Partially De-normalized
Vidhan
- Feb 23rd, 2018
A.) Completely Normalized
OM PRAKASH JHA
- Sep 7th, 2010
Fact table cntains factual data as well as composite key value with regard to all dimentional table.
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Pushdown Optimization
What is push down optimization ? what is its use and importance in data warehousing ?
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What type of Indexing mechanism do we need to use for a typical datawarehouse
Answered by on 2005-03-23 01:45:54: bitmap index
ibrarx
- Mar 7th, 2009
Hash Index - If we know that the hashing will result in uniform distribution and doesn't create hotspots (spikes-chaining).Bitmap Index - If the degree of cardinality is high for the attribute, me...
cetzhbo
- Jun 19th, 2007
Space requirements for indexes in a warehouse are often significantly larger than the space needed to store the data, especially for the fact table and particularly if the indexes are B*trees.Hence, y...
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What are conformed dimensions
jaggu_mandya
- Jan 11th, 2008
In Integrated schema Design, a dimension which can be shared across multiple fact tables is called Conformed Dimension.
Sivakumar.R
- Dec 7th, 2007
Any Dimensional Table in a Schema which is Shared by Two Facts Tables are called Conformed dimensions.
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What is ER Diagram
Answered by Puneet on 2005-05-07 04:21:07: ER - Stands for entitity relationship diagrams. It is the first step in the design of data model which will later lead to a physical database design of possible a OLTP or OLAP database
sukhdev_ce
- Apr 30th, 2009
The ER Diagrams is the initial process to analaysis a database application, and understands the problems related or causes in future with the choosed database application, in this satge different comp...
clickharri
- Apr 22nd, 2008
Entity Relationship Diagrams are a major data modelling tool and will help organize the data in your project into entities and define the relationships There are three basic elements in ER models: Ent...
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What is a dimension table
Answer posted by Riaz Ahmad on 2005-06-09 14:45:26: A dimensional table is a collection of hierarchies and categories along which the user can drill down and drill up. it contains only the textual attributes.
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Editorial / Best Answer
Answered by: Edmond
- Apr 13th, 2007
Let's be very clear. this is a very simple, and becomes a very confusing subject.
A fact table is an entity representing the numerical measurements of the business. A dimension table is the entity describing the textual representation of the business.
In a banking model, the account and balances are the measurements within the fact table, where customer name, social security, address, time period of the account, are the dimensions (customer/time).
Hope this answers the clarification.Anindya1281
- Jun 5th, 2011
In very simple termsFact : this contains all numeric attributesDimesion : this contains all non numeric , textual attributesIn order to rememberFact : Any answer to What user want to see is factfor ex...
mickey_gupta
- Mar 4th, 2009
Dimension table contains reference data which gives meaning to fact data. You can also view them as parameters across which you want to analyze the fact data.
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Explain the flow of data starting with OLTP to OLAP including staging ,summary tables,Facts and dimensions.
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jaggu_mandya- Member Since Jan-2008 | Jan 17th, 2008
OLTP(1)---->ODS(2)------>DWH(3)-------->OLAP(4)------------>Reports(5)------>decision(6)
1-2 (extraction)
2-3 (Transformation and here ODS is itself staging area )
3-4-5 (Use of reporting tool and generate reports)
6-decision is taken i,e purpose of datawarehouse is servedI think this is right picture
wnthanuja
- Jun 19th, 2008
Source System data ----------Extraction---------Transformation(Clenance the data according to business logics)(As dimensions)----------Takes data from the dimension tables in to fact tables using Surrogate keys---------------Load (As cubes)(In to the staging)
verma_tushar
- Mar 5th, 2008
In some of the cases Pre Stage is also a intermediate phase between the OLTP environment and actual staging area.The prestage is one where dta clensing, data profiling nad data validation takes place....
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What is the purpose of "Factless Fact Table"? How it is involved in Many to many relationship?
mri_sonam
- Dec 17th, 2008
Factless Fact Table is the fact table without having any measure (Transaction Data).The intention may vary from use but mostly its used for either Custom Reporting or Bridging. It contains only the k...
sixto.dsilva
- Oct 3rd, 2008
Best way of explaining the purpose of factless fact table is factless fact tables are the prefered method of recording evernts in a data warehouse where there is no natural numberic measurement associated with the event.
Data Warehousing Basics
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