View specification

The view specification contains the extensional operations for defining the view. This corresponds to the FROM , WHERE , GROUP_BY and HAVIN clause.

The FROM clause in the schema view refers to one or more collections (extents or class properties) or property paths, which define data sources but also the data type for following operations. For local view definitions, the view specification may be empty, in which case the view definition simply provides a number of additional attributes (or collection properties) derived from source instance properties.