Basics - what is junk dimension?what is the difference between junk dimension and degenerated dimension?

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what is junk dimension?
what is the difference between junk dimension and degenerated dimension?

Total Answers and Comments: 7

Last Update: April 06, 2007 Asked by: ganesh

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May 08, 2006 12:12:56

Jayashree

Member Since: February 2006 Contribution: 1

RE: what is junk dimension?what is the differenc...

A junk dimension is a collection of random transcational codes, flags and text attributes that are unrelated to any particular dimension.The junk dimension is simply a structure that provides the convienent place to store the junk dimension.

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May 10, 2006 16:40:48

Jyothsna

RE: what is junk dimension?what is the differenc...

A "junk" dimension is a collection of random transactional codes, flags and/or text attributes that are unrelated to any particular dimension. The junk dimension is simply a structure that provides a convenient place to store the junk attributes.where asA degenerate dimension is data that is dimensional in nature but stored in a fact table.

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May 30, 2006 03:21:47

ashok

RE: what is junk dimension?what is the differenc...

junk dimension

the column which we are using rarely or not used, these columns are formed a dimension is called junk dimension

degenerative dimension

the column which we use in dimension are degenerative dimension

emp table has empno.ename,sal,job,deptno

but

we are talking only the column empno,ename from the emp table and forming a dimension this is called degenerative dimension

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July 13, 2006 04:46:07

RE: what is junk dimension?what is the differenc...

Junk dimension: Grouping of Random flags and text Attributes in a dimension and moving them to a separate sub dimension.

Degenerate Dimension: Keeping the control information on Fact table ex: Consider a Dimension table with fields like order number and order line number and have 1:1 relationship with Fact table, In this case this dimension is removed and the order information will be directly stored in a Fact table inorder eliminate unneccessary joins while retrieving order information..

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September 01, 2006 13:51:30

mamathareddy

RE: what is junk dimension?what is the differenc...

hi ganesh

i think junck dim is a dimension combining all the small dim in to a big dim

the main diff between junck and degenerate are junck dim have source but where as degenerated dim are not having any source

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September 05, 2006 05:43:58

Rajkumar

what is junk dimension?what is the differenc...

A junk dimension is a convenient grouping of flags and indicators. It's helpful, but not absolutely

required, if there's a positive correlation among the values.

Their benefits:

Provide a recognizable, user-intuitive location for related codes, indicators and their

descriptors in a dimensional framework

Clean up a cluttered design that already has too many dimensions. There might be five

or more indicators that could be collapsed into a single 4-byte integer surrogate key in

the fact table

Provide a smaller, quicker point of entry for queries compared to performance from

constraining directly on these attributes in the fact table. If your database supports bit-

mapped indices, this potential benefit may be irrelevant, although the others are still

valid.

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April 06, 2007 05:03:43

Stephen

RE: what is junk dimension?what is the differenc...

Junk Dimension also called as garbage dimension.
A garbage dimension is a dimension that consists of low-cardinality columns such as codes, indicators, status,

and flags. The garbage dimension is also referred to as a junk dimension. Attributes in a garbage dimension are not

related to any hierarchy.

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