1. What is rank transformation?
A rank transformation is used to select top or bottom rank of data. This means, it selects the largest or smallest numeric value in a port or group. Rank transformation also selects the strings at the top or bottom of a session sort order. Rank transformation is an active transformation.
2. What is rank cache?
The integration service compares input rows in the data cache, if the input row out-ranks a cached row, the integration service replaces the cached row with the input row. If you configure the rank transformation to rank across multiple groups, the integration service ranks incrementally for each group it finds. The integration service stores group information in index cache and row data in data cache.
3. What is RANKINDEX port?
The designer creates RANKINDEX port for each rank transformation. The integration service uses the rank index port to store the ranking position for each row in a group.
4. How do you specify the number of rows you want to rank in a rank transformation?
In the rank transformation properties, there is an option 'Number of Ranks' for specifying the number of rows you wants to rank.
5. How to select either top or bottom ranking for a column?
In the rank transformation properties, there is an option 'Top/Bottom' for selecting the top or bottom ranking for a column.
6. Can we specify ranking on more than one port?
No. We can specify to rank the data based on only one port. In the ports tab, you have to check the R option for designating the port as a rank port and this option can be checked only on one port.
A rank transformation is used to select top or bottom rank of data. This means, it selects the largest or smallest numeric value in a port or group. Rank transformation also selects the strings at the top or bottom of a session sort order. Rank transformation is an active transformation.
2. What is rank cache?
The integration service compares input rows in the data cache, if the input row out-ranks a cached row, the integration service replaces the cached row with the input row. If you configure the rank transformation to rank across multiple groups, the integration service ranks incrementally for each group it finds. The integration service stores group information in index cache and row data in data cache.
3. What is RANKINDEX port?
The designer creates RANKINDEX port for each rank transformation. The integration service uses the rank index port to store the ranking position for each row in a group.
4. How do you specify the number of rows you want to rank in a rank transformation?
In the rank transformation properties, there is an option 'Number of Ranks' for specifying the number of rows you wants to rank.
5. How to select either top or bottom ranking for a column?
In the rank transformation properties, there is an option 'Top/Bottom' for selecting the top or bottom ranking for a column.
6. Can we specify ranking on more than one port?
No. We can specify to rank the data based on only one port. In the ports tab, you have to check the R option for designating the port as a rank port and this option can be checked only on one port.
7.
How does a Rank
Transform differ from Aggregator Transform functions MAX and MIN?
Like the Aggregator transformation, the
Rank transformation lets us group information. The Rank Transform allows us to
select a group of top or bottom values, not just one value as in
case of Aggregator MAX, MIN functions.
8. What is a RANK port and RANKINDEX?
Rank port is an
input/output port use to specify the column for which we want to rank the
source values. By default Informatica creates an output port RANKINDEX for each
Rank transformation.
It stores the ranking position for each row in a
group.
9. How can you get ranks based on different
groups?
Rank transformation
lets us group information. We can configure one of its input/output ports as a
group by port. For each unique value in the group port, the transformation
creates a group
of rows falling within the rank definition (top or
bottom, and a particular number in each rank).
10. What happens if two rank values match?
Ans. If two rank values match, they receive the
same value in the rank index and the transformation skips the next value.
11. What are the restrictions of Rank
Transformation?
• We can
connect ports from only one transformation to the Rank transformation.
• We can
select the top or bottom rank.
• We
need to select the Number of records in each rank.
• We can
designate only one Rank port in a Rank transformation.
12. How does a Rank Cache works?
During a session, the Integration Service
compares an input row with rows in the data cache. If the input row out-ranks a
cached row, the Integration Service replaces the cached row with the input row.
If we configure the Rank transformation to rank based on different groups, the
Integration Service ranks incrementally for each group it finds. The
Integration Service creates an index cache to stores the group information and
data cache for the row data.
13. How does Rank transformation handle string
values?
Rank transformation can return the strings
at the top or the bottom of a session sort order. When the Integration Service
runs in Unicode mode, it sorts character data in the session using the selected
sort order associated with the Code Page of IS which may be French, German,
etc. When the Integration Service runs in ASCII mode, it ignores this setting
and uses a binary sort order to sort character data.
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