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What is data cube technology used for?
Guest
- Jan 16th, 2007
Data can be viewed on a cube in multidimesional manner where we can see aggregated and summarized facts of variables/attributes .Thes is where olap comes into play.
obbantiga
- Jan 3rd, 2007
A multi-dimensional structure called the data cube. In short described as a data abstraction that allows one to view aggregated data from a number of perspectives. Conceptually, the cube con...
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How can you implement many to many relation in star schema model?
gopal
- Jan 25th, 2007
HiUpto my knowlege designers implementing this M-M relation asFirst break the schema to 1-M and M-1 relationsLet me correct if any thing is wrong
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What is fan trap? How do you find out? How do you resolve that loop? What is chasm trap? How do you find out? How do you resolve that loop? How you provide security for reports? Whenever you open a report it refresh automatically? How do set this. Can you use different database for different universes? What are the types of universes?
PANGANAMALA SRINIVAS
- May 9th, 2012
Fan trap: one of the schema-tables in your physical realization via an rdbms has a 1:many relationship between two slave-tables but there is no path between the two slave tables! So we are clueless ab...
johnftamburo
- Mar 19th, 2009
A fan trap is a many-to-many relationship between two fact tables, bridged by a dimension.
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What is the difference between aggregate table and materliazed view?
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joshmohit- Member Since Oct-2010 | Nov 3rd, 2010
Aggregate table is a generic term to represent the summaries built in a warehouse. MAterilaized view is the technical implementation of these aggregate tables. Though, Materialized views come with the database specific properties which might not be covered with the generic definition of aggregate tables.
Tom Haughey
- Apr 30th, 2012
?An aggregate table is a table that contains data that is summarized somehow, for example, it contains a summary of Customer by Product by Week. A more granular level of detail would be the transactio...
joshmohit
- Nov 3rd, 2010
Aggregate table is a generic term to represent the summaries built in a warehouse. MAterilaized view is the technical implementation of these aggregate tables. Though, Materialized views come with the...
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ETL testing
How can we do the ETL testing on Data WareHouse?
anita_09
- Sep 10th, 2009
ETL testing validates that data is transformed correctly from OLTP to data warehouse. Validating the data transformed includes following main verification points: Ensures that all expected...
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Types of Dimension
What are the types of dimensions? Can you explainthe each type in short?
priyank_divya
- Aug 28th, 2013
Conformed Dimension: Used across lines of businesses to gather information from across LOBs. Eg. if we want to know the deptnames where the avg salary of employees is more than the overall avg. Junk D...
Joe
- Aug 21st, 2012
1. Conformed Dimensions
2. Junk Dimensions -
Diff Between Primary Index And Primary Key
What is the main difference between Primary Index and Primary key in teradata? and can we have this two on same column?
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Read nth Row from a File using Sequential File Stage in Datastage
How to read nth Row from a File using Sequential File Stage in Datastage
Scenario is as follows:
I have only two stages in a job
SeqFileStage1------> SeqFileStage2
I have to read only 6th Row from File 1 and write it in File2. -
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What is critical column?
Anitha
- Feb 23rd, 2007
The columns(granular) that change the values over a perriod of time.
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What is the difference between Oracle and Teradata?
Priyanka Sathe
- May 8th, 2018
Teradata is a RDBMS used specially to build data warehousing applications.
The biggest strength of TD is parellelism.
TD distributes its workload evenly across its system and process it in parallel which makes it much faster than other databases.Martin Alvarez
- Mar 19th, 2012
Teradata and Oracle produce relational database management systems. What the previous answers do not provide are important facts about both platforms. Teradata products are a "combo" of hardware + so...
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What is the difference between mapping parameter & mapping variable in data warehousing?What are the types of variable available in data warehousing?
dhiveya.m
- Apr 22nd, 2009
Mapping parameter are the constant values (values never changes) and mapping variables are the values that ever changes.
fir_dan
- Jul 18th, 2008
A mapping parameter is a static value that you define before running the session and it retains the same value till the end of the session. Define a parameter in paramaeter file (.par) and use it in m...
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What is the use of data warehousing? Can we perform all the transformations using Oracle?
rmanikandan
- Apr 30th, 2008
Data warehousing is used to perform Historical records & providing all information by client users. Yes we can persom all the transformatioin usring oracle
prudhvi.g
- Sep 3rd, 2007
Datawarehousing is nothing but analysing the data and providing solutions to the business people.Major usage of datawarehousing is that it can analyse the data and stored the data which is historical.
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Staging and Operational Data Store
What are Staging and Operational Data Stores and what is their difference?
Why does one need staging and why does one need ODS? What will happen if they are not there? Who and how is it decided that a staging or ODS is needed? Which comes first staging or ODS?jryan999
- Feb 3rd, 2010
An Operational Data Store (ODS) is a repository of active "operational" data. It's typically used to hold data for a short period (eg. Days or weeks at most), to help the business ...
srilu1234
- Jan 19th, 2010
Stagining and operational data store are different databases.It can be one database aswell to reduce the cost to maitain two databases.Staging is the place where cleansing is done and Operational Stor...
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Suppose your filtering the rows using a filter transformation only the rows meet the condition pass to the target .Tell me where the rows will go that doesnot meet the condition.Thanks in advance
VVM.SP
- Mar 18th, 2008
In Filter Transformation Those row are not meet to the filter condition they are rejected. These rejected rows are appear in $PMBad.Dir
herbert
- Dec 9th, 2006
Yes there is folder or file in informatica which collects this rejected rows, its location is given while installing the s/w
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SCD types
What are the types of slowly changingdimension ?Can you explain please types of slowly changingdimension in detail ?
vijaya
- Aug 29th, 2012
Slowly changing dimensions are 3 types. In scd-1 new data is inserted by deleting old one. so latest information is stored. In scd-2 we can maintain history of data for a particular item. new data is...
bhavikumehta
- Jun 26th, 2012
SCD are of following types: type 1 - updates changes without preserving history type 2 - stores history data by maintaining versions of the updated data type 3 - either stores current and previous ver...
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What is diffrence between SAS tool and other tools.why SAS is so popular?
jag singh
- Jun 12th, 2007
SAS gets adopted by the business groups that do not have a large IT support staff as SAS provides the complete DW environment including ETL and reporting in one easy to manage package. See http://www.dwoptimize.com/2007/02/latest-data-warehouse-industry-trends.html for more comparisons.
mithunmca
- Mar 28th, 2007
Hi The SAS system is an integrated system of software products. The core of the SAS system is Base SAS software. plz visit the following link u will get a idea of w...
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What is data cleaning? How can we do that?
sub_guha
- Jan 25th, 2010
Data cleaning, technically called "Data Cleansing"is a group of methods for making data more reliable and accurate. Usually companies store data in warehouses so they can make meaning out of...
Hakoonamatata
- Jul 9th, 2007
Data cleaning is a self explainatory term. Most of the data warehouses in the world source data from multiple systems - systems that were created long before data warehousing was well understood, and ...
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Difference between Database and Datawarehouse
What are the difference between a database and data warehouse?
gtomar
- Jul 28th, 2008
Database :- database is a collection of related information stored in a structured form in terms of table so that It makes easier insertion, deletion and mainupulation of data. database consist of tab...
ashuboy12345678
- Jul 27th, 2008
Database is a collection of mostly recent data. Where as Datawarehouse consist of historical data the size can vary upto 100 GB or more.Datawarehouse is a combination of datamart used mainly knowledge processing.
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Surrogate Key
Why do we use Surrogate Key?
Rajesh Swarnkar
- Feb 28th, 2012
Usually Surrogate keys are System Generated keys that can be used in place of missing primary key.
sadique_ghitm
- Nov 25th, 2011
A surrogate key in a database is a unique identifier for either an entity in the modeled world or an object in the database. The surrogate key is not derived from application data. A surrogate repres...
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