Interested to Buy Any Domain ? << Click Here >> for more details...
What are the types of lookup?
- 3 Answers
- 18382 Views
- Wipro, I also Faced
- E-Mail Answers
Answers were Sorted based on User's Feedback
Answer / sandeep
Differences Between Connected and Unconnected Lookup:
connected
o Receives input values directly from the pipeline.
o uses Dynamic or static cache
o Returns multiple values
o supports user defined default values.
Unconnected
o Recieves input values from the result of LKP
expression in another transformation
o Use static cache only.
o Returns only one value.
o Doesn’t supports user-defined default values.
NOTES
o Common use of unconnected LKP is to update slowly
changing dimension tables.
o Lookup components are
(a) Lookup table. B) Ports c) Properties d) condition.
Lookup tables: This can be a single table, or you can
join multiple tables in the same Database using a Lookup
query override.You can improve Lookup initialization time
by adding an index to the Lookup table.
Lookup ports: There are 3 ports in connected LKP
transformation (I/P,O/P,LKP) and 4 ports unconnected LKP
(I/P,O/P,LKP and return ports).
o if you’ve certain that a mapping doesn’t use a
Lookup ,port ,you delete it from the transformation. This
reduces the amount of memory.
Lookup Properties: you can configure properties such as SQL
override .for the Lookup,the Lookup table name ,and tracing
level for the transformation.
Lookup condition: you can enter the conditions ,you want
the server to use to determine whether input data qualifies
values in the Lookup or cache .
when you configure a LKP condition for the transformation,
you compare transformation input values with values in the
Lookup table or cache ,which represented by LKP ports .when
you run session ,the server queries the LKP table or cache
for all incoming values based on the condition.
NOTE
- If you configure a LKP to use static cache ,you
can following operators =,>,<,>=,<=,!=.
but if you use an dynamic cache only =can be used .
- when you don’t configure the LKP for caching ,the
server queries the LKP table for each input row .the result
will be same, regardless of using cache
However using a Lookup cache can increase session
performance, by Lookup table, when the source table is
large.
Performance tips:
- Add an index to the columns used in a Lookup
condition.
- Place conditions with an equality opertor (=) first.
- Cache small Lookup tables .
- Don’t use an ORDER BY clause in SQL override.
- Call unconnected Lookups with :LKP reference
qualifier.
| Is This Answer Correct ? | 17 Yes | 2 No |
What is best approach to load 100 different source files (Different structure) to differet target tables ?
what is degenerated dimension?
Create a mapping which contains 2 target tables. When the session runs for the first time it shud load Target table 1 and when it runs for second time it shud load Target table 2.
how i will stop my workflow after 10 errors
Can we create two repositories on same database instance in oracle?
What is the difference between power center and power mart? What is the procedure for creating independent data marts from informatica 7.1?
From where we can start or use pmcmd?
what is diff b/t sorter t/r and agg have the option sorter property...
write a query to follwoing table amount year quarter 254556 2003 first 546332 2003 second 129034 2003 third 490223 2003 fourth 165768 2004 first 265443 2004 second 510412 2004 third 435690 2004 fourth i want the output year q1_amount q2_amount q3_amount q4_amount 2003 254556 546332 129034 490223 2004 165768 265443 510412 435690
Hi all, iam new to informatica, can anyone tell me what is unit testing & how it is done? thank u
Consider a Phone Log table as below. It records all phone numbers that we dial in a given day. SOURCE_PHONE_NUMBER DESTINATION_PHONE_NUMBER CALL_START_DATETIME 1234 4567 01/07/2011 10:00 1234 2345 01/07/2011 11:00 1234 3456 01/07/2011 12:00 1234 3456 01/07/2011 13:00 1234 4567 01/07/2011 15:00 1222 7890 01/07/2011 10:00 1222 7680 01/07/2011 12:00 1222 2345 01/07/2011 13:00 Please provide an SQL query to display the source_phone_number and a flag where the flag needs to be set to Y if first called number and last called number are the same and N if the first called number and last called number are different. Desired Output: Source Number Is_Match 1222 N 1234 Y
without dynamic lookup transformation how to insert new rows and update existing rows?
Teradata 
