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How do you connect two fact tables ? Is it possible ?
sixto.dsilva
- Sep 20th, 2008
As comment by lot of DWH gurus above, two fact tables can be connected only using conformed dimension, defination of conformed dimension:if one primary key of dimension is defined in two fact tables it is called conformed dimension.
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How data in datawarehouse stored after data has been extracted and transformed from hetrogeneous sources and where does the data go from datawarehouse.
sharuvijay
- Jan 29th, 2009
Data is stored in DW in a relational, aggregatted (if needed), denormalized fashion where the data can be easily analysed.
sixto.dsilva
- Sep 11th, 2008
Data will stored in fact's and dimensional tables, the relational database can be Oracle, Informatic or netezza, it purely depends upon the company which technology they want to go for.
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What Snow Flake Schema
Answered by Girinath.S.V.S on 2005-03-17 06:40:48: Snowflake schemas normalize dimensions to eliminate redundancy. That is, the dimension data has been grouped into multiple tables instead of one large table. For example, a product dimension table in a star schema might be normalized into a products table, a product_category table, and a product_manufacturer table in a snowflake schema. While this...
prodyot.sarkar
- May 13th, 2010
Snow-flake schema is a logical arrangement of tables in dimensional modeling where a centralized fact table references number of other dimension tables; however, those dimension tables are further nor...
harshadapj
- Jul 22nd, 2008
Closely related to the star schema, the snowflake schema is represented by centralized fact tables which are connected to multiple dimensionsIn the snowflake schema, however, dimensions are normalized...
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What is data mining
Answered by Puneet on 2005-05-07 04:24:28: Data mining is a process of extracting hidden trends within a datawarehouse. For example an insurance dataware house can be used to mine data for the most high risk people to insure in a certain geographial area.
kumarram
- Jun 11th, 2010
Data mining is the concept of extracting information from large data bases likes data wharehouse.
raj.rajeev15
- Sep 13th, 2009
Datamining is nothing but a science of finding information from databases or datasets.
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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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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.
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Can you convert a snowflake schema in to star schema?
idanh79
- Dec 1st, 2009
Yes, you can do it by denormalization of the dimensions into one (and wide) dimension, it is depends of your needs.Idan Halfon
sixto.dsilva
- Sep 25th, 2008
Yes right said both model are designed for different purpose , I think star schema is very informative for business users unlike snowflake which is bit complicated with lot of small , small tables. If...
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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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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.
Data Warehousing Basics
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