Wednesday, February 24, 2016

Rank Transformation In Informatica

Rank Transformation

Ø  A Rank transformation can be used to return the largest or smallest number of value in a port or a group
Ø  You can select only the top or bottom ranks of data using Rank transformation
Ø  You can connect ports from only one downstream transformation to the Rank transformation.
Ø  You can also create local variables and write non-aggregate expressions in rank transformation.
Ø  The Integration Service stores group information in an index cache and row data in a data cache.
Ø  The rank transformation creates a RANKINDEX port for each Rank transformation
Ø  The Integration Service uses the Rank Index port to store the ranking position for each row in a group
Ø  The defult output port that gets created when you add a Rank transformation to a mapping is RANKINDEX port
Ø  When two records are having same data in ranking columns the rank transformation generate same rank to both the records.
Ø  In rank transformation you can define groups based on more than one column but you can define ranking only based on values of only one column.

Ø  To find ranks within a grops of data we need to group data using group by columns option under ports tab.

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