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What is Normalization, First Normal Form, Second Normal Form , Third Normal Form
Answer posted by Badri Santhosh on 2005-05-18 09:40:29: Normalization : The process of decomposing tables to eliminate data redundancy is called Normalization. 1N.F:- The table should caontain scalar or atomic values. 2 N.F:- Table should be in 1N.F + No partial functional dependencies 3 N.F :-Table should be in 2 N.F + No transitive dependencies
dstorkey
- Mar 24th, 2009
To paraphrase the oath, and help you remember, in 3rd normal form data in the table depends on the key, the whole key, and nothing but the key.
Jyothsna Tallapally
- May 10th, 2006
Normalization:It is the process of efficiently organizing data in a database.There are 2-goals of the normalization process: 1. Eliminate redundant data 2. Ensure data dependencies make sens...
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What does level of Granularity of a fact table signify
ibrarx
- Mar 7th, 2009
The level of granularity of a fact table signifies the smallest unit of analysis.
ravi kumar guturi
- Mar 9th, 2006
Granularity means nothing but it is a level of representation of measures and metrics.The lowest level is called detailed dataand highest level is called summary dataIt depends of project we extract fact table significanceBye
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What are Semi-additive and factless facts and in which scenario will you use such kinds of fact tables
divya29july
- Feb 11th, 2010
Factless Fact table:Consider an example of Product on promotion, the fact table will contain information of only the products that were on sale and sold but not of those that did not sell as the fact ...
siraj.khan
- Aug 3rd, 2007
Semi-additive facts are those facts which can be aggregate according to the context. so, it can contain a fact but the factless fact table does not contain fact's but it contains the dimmentions. It's a type of a dimmentions.
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Differences between star and snowflake schemas
Answered by sudhakar on 2005-05-09 18:32:18: star schema uses denormalized dimension tables,but in case of snowflake schema it uses normalized dimensions to avoid redundancy...
sk.rafee
- Apr 26th, 2006
Star schema uses denormalized dimension tables,but in case of snowflake schema it uses normalized dimensions to avoid redundancy...
Guest
- Feb 13th, 2006
Star Schema &n...
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What is the main differnce between schema in RDBMS and schemas in DataWarehouse....?
Sam Kolta
- Apr 17th, 2010
User It is just an account name for the user Owns a schema Have the same name Create user command, create the user User can be considered schema User can created without schema It is the account for t...
senthil kumar B
- Feb 13th, 2006
Diff b.w OLTP and OLAP :------------------------OLTP Schema :* Normalized * More no.of trans* Less time for queries execution* More no.of users* Have Insert,delete and update trans. OLAP (D...
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What is meant by metadata in context of a Datawarehouse and how it is important?
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kalpit
- Mar 10th, 2009
Metadata is the Information about the Data which is being stored in DWH , Why its imp : 1. To know the flow of source data into Data Warehouse, 2. In case if you have many star schema or many subjec...
thumatinagaraju
- Oct 24th, 2006
Meta data is stored in repository only not in dataware house .. but we r placing our repository in database in that way ur correct ,,but not directly stored in the dataware house plz check it mam
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Which automation tool is used in data warehouse testing?
Santosh
- Jul 3rd, 2015
Datagaps ETL Validator has a lot of inbuilt features for ETL Testing automation. We are using it.
ora.amar
- Aug 5th, 2014
We can use Data Validation option DVO provided by informatica corporation to automate etl testing.
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What are Aggregate tables
kevin0209
- Aug 30th, 2010
Aggregate table contains summarised data. The materialized view are aggregated tables.
sixto.dsilva
- Oct 1st, 2008
Aggregate table contains the summary of existing warhouse data , it contains data which is group accordingly (month , quartely etc) depending upon the business needs.For example you may contain transa...
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What is real time data-warehousing
ashwinijawalgekar
- Jul 7th, 2010
The Real time data warehouse is really a combination of real time (Current) and historical data warehouse.In real time world the historical systems are less valuables because of issues facing managers...
satyambabu
- Mar 22nd, 2006
Real time Data warehousing means combination of hetrogenious databases and query and analysis purpose and Decisionmaking and reporting purpose.
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How do you load the time dimension
manisha.sinha
- Dec 29th, 2006
create a procedure to load data into Time Dimension. The procedure needs to run only once to popullate all the data. For eg, the code below fills up till 2015. You can modify the code to suit the feil...
Raghunath Bhairavajosula
- May 12th, 2006
Generally we load the Time dimension by using SourceStage as a Seq File and we use one passive stage in that transformer stage we will manually write functions as Month and Year Functions to load the ...
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What is the main FUNCTIONAL difference between ROLAP,MOLAP,HOLAP?
(NOT AS A RELATIONAL,MULTI, HYBRID?)
ThomasB
- Jan 4th, 2008
The FUNCTIONAL difference between these is how they information is stored. In all cases, the users see the data as a cube of dimensions and facts.ROLAP - detailed data is stored in a relational ...
Sivakumar.R
- Dec 7th, 2007
Rolap : Relational Olap,these functionality are used in Business Objects.Molap : Multi Dimensional Olap Functionality are used in Cognos.Hloap : Hybrid Olap is a combination of Rolap and Molap.
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What is a CUBE in datawarehousing concept?
desaial
- Aug 20th, 2007
CUBE is used in DWH for representing multidimensional data logically. Using the cube, it is easy to carry out certain activity e.g. drill down / drill up, slice and dice, etc. which enables the ...
jahnavi.s
- Sep 20th, 2006
Yes,cube is a logical representation of data.12 steps are required for the creation of cubes.its mainly used for analysis purpose. we can analyse which product can be sold more in which country all these we available in the cube by performing operatoins like roll-up,drill-down,slice and dice
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What are the possible data marts in Retail sales.?
ABHI2411
- Jan 8th, 2009
The possible Data Marts in Retail Sales can be-1) Sales-Sales Order Management and Customer related.Accounts receivables2) Purchase-Purchase Order management and Vendor related.Accounts payables3) Fin...
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What is the difference between view and materialized view
mri_sonam
- Dec 18th, 2008
ViewsA view takes the output of a query and makes it appear like a virtual table. You can use a view in most places where a table can be used.All operations performed on a view will affect data in the...
vijay
- Jul 13th, 2006
View?is a logical reference to a database table. But Meterial View is actual table and we can refresh data in time intervels. If you made any change in database table that change will effect into view but not meterialize view..
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What is source qualifier?
kalyani
- Mar 28th, 2007
Source qualifier is a transformation which extracts data from the source. Source qualifier acts as SQL query when the source is a relational database and it acts as a data interpreter if the source is a flatfile.
sandrag
- Feb 7th, 2007
Source qualifier is an transformation which every mapping should have , it defines the source metadata to the Informatica Repository.The source qualfier has different properties like filtering records , and joining of two source , and so on .
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What is VLDB
Answered by Kiran on 2005-05-06 20:12:19: The perception of what constitutes a VLDB continues to grow. A one terabyte database would normally be considered to be a VLDB.
sithusithu
- Jan 9th, 2006
Very Large Database (VLDB)it is sometimes used to describe databases occupying magnetic storage in the terabyte range and containing billions of table rows. Typically, these are decision support systems or transaction processing applications serving large numbers of users. Cheers,Sithu
Muhammed Kamal
- Aug 30th, 2005
VLDB stands for Very Large Data Base, any database too large (normally more than 1TB) cosidered as VLDB.
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Is it correct/feasible develop a Data Mart using an ODS?
the ODS is technically designed to be used as the feeder for the DW and other DM's -- yes. It is to be the source of truth.Read the complete thread at http://asktom.oracle.com/pls/ask/f?p=4950:8:16165205144590546310::NO::F4950_P8_DISPLAYID,F4950_P8_CRITERIA:30801968442845,
ravi_kumar_garre
- Nov 14th, 2007
Hi According to Bill Inmon's paradigm an enterprize can have one datware house and datamarts source their information from the datawarehouse. In the dataware house, information is stroed in 3rd No...
Aruna
- Dec 22nd, 2006
Data Mart is a sub section of Data Warehouse. e.g there is a datawarehouse of a company.Supose there is a datamart for all its departments. The complete company stores large historical data.In this case datamart of a deparment also stores historical data. can ODS be used here?
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Data Warehousing Basics
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