difference between connected and unconnected lookups

[vspk]

Hi,
can any one elaborate more on connected and unconnected look ups.
i know that connected can be used in the pipe line and unconnected lookups can be called from an expression and returns a value .
other than these are there any major differences...
pls do let me know.

thanks
vspk

 

[blom0344]

This is covered extensively in INFA's excellent manuals which you own if you are using Powermart/Powercenter.

The biggest difference I guess is that an unconnected lookup can only return one port, the connected one multiple ports.

If no match is found for the lookup condition the connected one can return default value for all ports, where the unconnected one returns 'null'

My suggestion would be to stick to unconnected ones; connected ones tend to mess up mappings, making them harder to 'read'


T. Blom
Information analyst
tbl@shimano-eu.com

 

[jlito]

Hi Blom,

How about the performance? If I want to return only one column from the lookup? Which lookup will return the value faster?

Rgds,
jlito

 

[Sridharan]

If you want to return only one column then go for Unconnected Lookup.

Sri