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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 non-additive facts
sharuvijay
- Jan 28th, 2009
Non Additive facts cannot be aggregrated along with dimenstion in the fact table. For eg. Age, weather
vineela
- Jul 18th, 2007
Non additive facts are the facts that do not participate in arithmetic caliculations. for example in stock fact table there will be opening and closing balances along with qty sold and amt etc. but opening and closing balances were never used in arithmetic calculations.
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Why are OLTP database designs not generally a good idea for a Data Warehouse
Answer posted by Shri Dana on 2005-04-06 19:04:05: OLTP cannot store historical information about the organization. It is used for storing the details of daily transactions while a datawarehouse is a huge storage of historical information obtained from different datamarts for making intelligent decisions about the organization.
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What is a linked cube?
A cube can be stored on a single analysis server and then defined as a linked cube on other Analysis servers. End users connected to any of these analysis servers can then access the cube. This arrangement avoids the more costly alternative of storing and maintaining copies of a cube on multiple analysis servers. linked cubes can be connected using TCP/IP or HTTP. To end users a linked cube looks like...
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Explain the situations where snowflake is better than star schema
DWAlchemist
- Apr 11th, 2008
A snowflake schema is a way to handle problems that do not fit within the star schema. It consists of outrigger tables which relate to dimensions rather than to the fact table.The amount of spac...
ghoshkunal123
- Feb 5th, 2008
Star schema is good for simple queries and logic. But snowflake schema is good for complex queries and logic. Snowflake schema is nothing but an extension of the star schema in which the dimension tables are further normalized to reducy redundancy. Hope this helps.
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Explain ODS and ODS types.
chand.abinitio
- Sep 27th, 2010
ODS is defined as subject-oriented and integrated data and volatile
repository of data.
Contains current or near to current data
could be used for day to day reporting/ low-level analysis
updatable data store
contains detail data, no summarization
data in homogeneous form.
jaggu_mandya
- Jan 11th, 2008
It is designed to support Operational Monitoring. It is subject oriented,integrated database which holds the current,detailed data.data here is volatile
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What is DATA integration
OM PRAKASH JHA
- Sep 7th, 2010
Data integration involves data combining in different residing in different sources and providing users with a unified view of these data.This process becomes significant in a variety of situations bo...
tisha24
- Oct 22nd, 2009
Data from different sources (like flatfiles, CSV, oracle, db2,teradata, mainfraes etc.) are extracted and transformed in to a single specific pattern (unique structure) and is know as integration of d...
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Bridge Table
What is the use of bridge table. Can give a simple example?
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Editorial / Best Answer
Sirini- Member Since Jun-2009 | Jun 14th, 2009
An example of a Bridge table would be relationship table between student_master and courses_master. A Student may participate in multiple courses and obviously in a course there will be multiple students. In this scenario to maintain relationships between student_master and courses_master we need another table, which may be called, Student_courses. This table will have all relationships between Students and Courses.A bridge table is a table that only contains the keys between the two tables in a many-to-many relationship. These tables typically consist of mostly key fields, the primary keys of the two tables needing the many to many relationships. Sometimes there are more data elements, but often there are only two columns, both foreign keys.
vijsarav11
- Oct 19th, 2009
Hi all... This is my view on bridge tables:Bridge table in simple can be called as reference tables. As the name indicates, this table can be used to link two tables with 1 reference id...
tisha24
- Oct 7th, 2009
A table which maintained to define the relationship between two different tables is known as bridge tables. For example, say there are two tables one table with employee information (an employee table...
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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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Data Warehousing Basics
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