Connected vs. Unconnected Lookup Transformation in Informatica

Connected Lookup Transformation:

• Connected lookup is a type of lookup transformation that is connected directly to the source or target in the Informatica mapping.
• It is used when the lookup table is linked directly to the source or target, and it receives input values from the mapping pipeline.
• It helps in performing lookups and returning the matched values to the mapping for further processing.
• Connected lookup is efficient for large data sets as it processes records in bulk.

Unconnected Lookup Transformation:

• Unconnected lookup is a type of lookup transformation that is not directly linked to the source or target in the mapping.
• It is invoked within an expression or another transformation in the mapping whenever a lookup is needed.
• It does not have any input/output ports and is not connected directly to the mapping pipeline.
• Unconnected lookup is useful in scenarios where lookups are required within an expression or custom function in the mapping.

Overall, the main difference between connected and unconnected lookup transformations in Informatica lies in their direct connection to the source/target and their invocation within the mapping pipeline. Choose the appropriate type based on your specific requirements and mapping design.