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what is a derived table in data warehousing?

Asked by: Interview Candidate | Asked on: Jun 29th, 2006
Showing Answers 1 - 12 of 12 Answers
senthil

Answered On : Jun 30th, 2006

hi

    it is similar to views,it is mainly used to restrict the datas

  
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MuthuKumar

Answered On : Jul 21st, 2006

Can u pls give me the exact defination and examples ?

  
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Senthil Raj

Answered On : Aug 3rd, 2006

we cont use correlated subquery in BO 6.5( Im not sure with other version).

In such cases we use Derived tables. 

  
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pratip

Answered On : Jan 10th, 2007

respected all

Actually am a BO XI beginner ,so have stuck in  the basic concept of derived table..if any one explain it for me,i ll be grateful to them,and plz explain in which context i should use the derived table.

thankyou

pratip

  
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Vineela

Answered On : Apr 26th, 2007

Derived tables are not real tables at the Database level , but are the selection of few columns in the Table with some aggregations, specific to the report.

This feature is available in BO 6.5 and later versions.

Sel a1,a2,a3,max(a4)

from a ,

(Sel b1, b2, max(b3) as B3, Min(B4) as B4 from B group by b1,b2) as BX

where BX.B1= a.a1
group by a1,a2,a3
order by a1,a2,a3

The (Sel b1, b2, max(b3) as B3, Min(B4) as B4 from B group by b1,b2) in the above query is a derived table.

The same definition has to be added in the Universe - by going into Insert >> Derived Tables.

Type the Query - parse it and the new table inserted can be used to any type of join / Contexts etc in the Universe.

Yes  1 User has rated as useful.
  
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kiran

Answered On : May 15th, 2007

Derived tables is an option in Business Objects Tool(Business Intelligence) from version 6.5.

  
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sunil

Answered On : Jun 3rd, 2007

For Derived table, i am having one scenario.
My Database table is having following Column
-Empno
-Empname
-Managerno

my Report Requirement is like:
report should display Emp name and its corressponding manager name.

Based on this reqquirement, i need to design Universe.

My steps would be like this:
1.Looking at the requiement, i would go for Derived table, having name Manger.

Derived Table(Manager) would be having following syntax.

select distinct a.EmpNo,b.EmpName from Emp a,Emp b
where a.ManagerNo=b.EmpNo

2. Joining

2. Create class Manager and Object Manager Name, Source for this object would be
Derived_table.EmpName that is manager. EmpNo. Here EmpNo is coming from Derived table syntax.

Now my universe is ready.

As per the repoer requirement i can create report.

So Bottom line is Derived table plays a major role in this scenario.

  
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goutham438

Answered On : Jul 31st, 2011

View all answers by goutham438

derived table is the table which is created in the universe itself

we create the new variable using variable editor in webi or deski in the report panel using a function but it is used for one single report. if we create the variable using derived table using universe itself it can be used for multiple reports and multiple universe's

  
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pujitha

Answered On : Sep 14th, 2011

Derived tables are tables that you can define in the universe schema. You create objects on them as you do with any other object.

  
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venkat

Answered On : Oct 31st, 2011

Derived tables can be defined by an sql query at the university level that can be used as a logical table in designer.
It is not physical table in universe schema.The advantage of this derived table is reduced amount of data returned
to the document for analysis.

  
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lionskashif

Answered On : Aug 30th, 2012

View all answers by lionskashif

Derived Table is a Virtual and Dynamic table in schema. It is not a Physical table but Act like a Physical table.
why we make that? We can create/store most usable Dimension in it to reuse frequently to access the data.
It saves your time to retrieve the data and giving you better performance in Universe and Reporting side.

cheers.....lionskashif

  
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vyankatesh valakate

Answered On : Oct 19th, 2012

Derived tables can define the suquery of a Table. derived table has a query in the form of Logical tables in designer to accomplish task by writting query in query panel.

  
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