The following list defines some of the terms referred to in this chapter.
The persistent schema abstraction (persistent entities, their state, and their
relationships) over which queries operate. The query language translates queries
over this persistent schema abstraction into queries that are executed over
the database schema to which entities are mapped.
Abstract schema type: All expressions
evaluate to a type. The abstract schema type of an entity is derived from
the entity class and the metadata information provided by Java language annotations.
Backus-Naur Form (BNF):
A notation that describes the syntax of high-level languages. The syntax diagrams
in this chapter are in BNF notation.
traversal of relationships in a query language expression. The navigation
operator is a period.
An expression that navigates to a entity’s state or relationship field.
field: A persistent field of an entity.
field: A persistent relationship field of an entity whose type
is the abstract schema type of the related entity.