⟩ Explain difference between transfer rule&update rules?
In context to BW/BI 3.x
transfer rules - mapping the fields in the datasource to the infoobjects in Infosource or target fields. it help you to distinguish which all fields in the datasource are required in the infoobjects in the Infosource.
update rules - to update something. here it revolves around a source(infosource)and a target(data target). update rules are used to update the data targets.you have to create update rules if you supply a data target from an InfoSource with flexible update.
In BI 7.0 Transforamtion - (Tranfer and update rules)