Explain what are the differences between Unconnected and Connected lookup?

Connected Look up Unconnected Look up
Connected look up participates in mapping – It is used when look up function is used instead of an expression transformation while mapping
Multiple values can be returned – Only returns one output port
It can be connected to another transformations and returns a value Another transformation cannot be connected
Static or dynamic cache can be used for connected Look up Unconnected as only static cache
Connected look up supports user defined default values Unconnected look up does not support user defined default values
In Connected Look up multiple column can be return from the same row or insert into dynamic look up cache Unconnected look up designate one return port and returns one column from each row