What are Different Types of Dimensions in DataWarehouse?
What is Dimension in Datawarehouse?
Anything which measure facts like time,length,status,ID,date,place,codes,flags with its description,audit and other attributes is stored in table is called as dimension. It contains the description of the buisness, without dimensions it is very difficult to measure the facts. Dimension is the attribute of facts.
Types of dimension in Datawarehouse?
The dimensions which carries same measurable value,no matter in which fact table it is used and joined.
For Example, time column will carry same meaning and attributable value in “Employee wages Table” and “Sales table”.
It is nothing but the collection of ‘N’ number of codes and flags, which are together being stored in one Dimension Structure as unique dimension build from combination of two or more dimensions.
For Example, If Table A contains two flags with employee Status-Permanent and Temporary as ‘F’ and ‘T’ and Table B with Pay unit contains-Monthly and weekly as ‘M’ and ‘W’ code then we can have Table C as Dimension Structure having four flags with the combinations of codes from the two Tables A and B as ‘FM’,’FW’,’TW’,’TM’. In this case Table C is the Junk Dimension, having combination of dimensions.
The dimensions which doesn’t exist as an individual dimension values but are derived from the existing facts tables.
For Example, Gender Code in Employee Information fact table.
The dimension which play different character in the same database,having multipurpose implementations like dimension date can be used as “Date of hire”, “Date of termination” and “Date of purchase”.
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