Database Reference
In-Depth Information
Rank index
When you create a Rank transformation, a default column called rank index gets created. If
required, this port can generate numbers indicating the rank. This is an optional field that
you can use if required. If you do not wish to use rank index, you can leave the port uncon-
nected.
Suppose you have the following data belonging to the
SALARY
column in the source:
Salary
100
1000
500
600
1000
800
900
When you pass the data through a Rank transformation and define a condition to get the top
five salaried records, the Rank transformation generates the rank index as indicated here:
Rank_Index, Salary
1,1000
1,1000
3,900
4,800
5,600
As you can see, the rank index assigns
1
rank to the same salary values, and
3
to the next
salary. So if you have five records with
1000
as the salary in the source along with other
values, and you defined conditions to get the top five salaries, Rank transformation will
give all five records with a salary of
1000
and reject all others.
With this, we have learned all the details of Rank transformation.
