VLDBJ 05 -Annotations on Relational DBS

"An Annotation Management System for Relational Databases", Deepavali Bhagwat, Laura Chiticariu, Wang-Chiew Tan, Gaurav Vijayvargiya

• Introduces a system to annotate the source data. They store annotations in a special attribute
  
• Describe 3 methods to propagate the annotations, motivated by different needs:
• • custom
  • default scheme: if the output data is copied then the annotation is propagated
  • default-all scheme: propagate annotations according to where the data is copied from in ALL equivalent formulations of the given query
• a new SQL language is introduced (pSQL). This extension supports PROPAGATE clause which allow a user to specify how annotations should be propagate. Does not support aggregates and bag semantics (i.e. DISTINCT keyword must be present)