Informatica - Unconnected Lookup

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Unconnected Lookup

In which situation do we use unconnected lookup?

Total Answers and Comments: 6

Last Update: November 10, 2009 Asked by: saravanan.eswaran

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Submitted by: pooja.verma

Unconnected lookup should be used when we need to call same lookup multiple times in one mapping. For example, in a parent child relationship you need to pass mutiple child id's to get respective parent id's.

One can argue that this can be achieved by creating resusable lookup as well. Thats true, but reusable components are created when the need is across mappings and not one mapping. Also, if we use connected lookup multiple times in a mapping, by default the cache would be persistent.

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aks_27, avneeshrathor

May 13, 2009 10:45:44

gazulas

Member Since: January 2006 Contribution: 22

RE: Unconnected Lookup

It all depends upon the situation. If you didn't want to use dynamic cache or if you didn't want more than one return port ..etc then u can use unconnected lkp.

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May 20, 2009 01:30:31

smsreddy

Member Since: May 2009 Contribution: 5

RE: Unconnected Lookup

1. When the return value is one then go for unconnected.
2. Most important one is you want return value in some conditions/cases then go for Unconnected to increase the performance of job.

For eg: you have 1 Million records and you want to have some return value for only half million based on some condition if commission < 100 then we want return value. This kind of cases will go for this.

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June 02, 2009 02:34:11

pooja.verma

Member Since: June 2009 Contribution: 2

RE: Unconnected Lookup

Unconnected lookup should be used when we need to call same lookup multiple times in one mapping. For example in a parent child relationship you need to pass mutiple child id's to get respective parent id's.

One can argue that this can be achieved by creating resusable lookup as well. Thats true but reusable components are created when the need is across mappings and not one mapping. Also if we use connected lookup multiple times in a mapping by default the cache would be persistent.

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July 16, 2009 02:10:44

sahan

Member Since: July 2009 Contribution: 10

RE: Unconnected Lookup

You can use the unconnected lookup when you need to call the same lookup multiple times in one mapping.

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October 03, 2009 03:54:40

subbarao_mvs

Member Since: October 2009 Contribution: 2

RE: Unconnected Lookup

Unconnected lookup is used to call the same lookup with different values to get output as single value in the same mapping. Generally unconnected lookup we can call from expression transformation.

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November 10, 2009 11:59:43

ktoscano

Member Since: November 2009 Contribution: 1

RE: Unconnected Lookup

The advantage of using an Unconnected Lookup is that the Lookup will be executed only when a certain condition is met and therefore improve the performance of your mapping. If the majority of your records will meet the condition then an unconnected lookup would not be an advantage. An example would be if I need to populate or update a value only for Customers living in California. I would execute my lookup only when State 'CA'.

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