Dimensions

• Available Information
  materialized view, base relations, other views, integrity constraints, etc.
• Allowable Modifications
  insertions, deletions, updates, sets of each, group updates, change view definition, etc.
• Expressiveness of the View Definition Language
  conjunctive queries, duplicates, aggregation, union, recursion, negation, select, project, join, spj, etc.
• Database Instance
• Complexity
  • Complexity of the View Maintenance Language
  • Complexity of the View Maintenance Algorithm
  • Complexity of Auxiliary Information (in terms of space)