Focus Keyword: Connected and Unconnected Lookup in Informatica

When discussing lookup transformations in Informatica, it's essential to understand the distinctions between connected and unconnected lookups.

Connected Lookup

In a connected lookup, the lookup transformation is connected directly to the source in the mapping. This means that the lookup transformation is directly connected to the pipeline flow of the mapping and can return multiple rows.

Unconnected Lookup

On the other hand, an unconnected lookup is not directly connected to the pipeline flow in the mapping. Instead, it is called by an expression within another transformation. Unconnected lookups are used when the lookup function needs to be reused in multiple places within the mapping.

Key Differences Summary:

• Connected lookup is directly connected to the mapping flow, while unconnected lookup is called by an expression in another transformation.
• Connected lookup can return multiple rows, whereas unconnected lookup returns a single output value.
• Unconnected lookups are ideal when reusing the lookup function, while connected lookups are suitable for direct integration into the mapping flow.

Understanding the differences between connected and unconnected lookups in Informatica is crucial for mapping design and data integration strategies.