Where do we use connected and unconnected lookups? | ETL Testing Interview Questions

If return port only one then we can go for unconnected. More than one return port is not possible with Unconnected. If more than one return port then go for Connected.
If you require dynamic cache i.e where your data will change dynamically then you can go for connected lookup. If your data is static where your data won't change when the session loads you can go for unconnected lookups .