Terminology

Abstract schema: The part of an entity bean's deployment descriptor that defines the bean's persistent fields and relationships.

Abstract schema name: A logical name that is referenced in EJB QL queries. You specify an abstract schema name for each entity bean that uses container-managed persistence.

Abstract schema type: All EJB QL expressions evaluate to a type. If the expression is an abstract schema name, by default its type is the local interface of the entity bean for which the abstract schema name is defined.

Backus-Naur Form (BNF): A notation that describes the syntax of high-level languages. The syntax diagrams in this chapter are in BNF notation.

Navigation: The traversal of relationships in an EJB QL expression. The navigation operator is a period.

Path expression: An expression that navigates to a related entity bean.

Persistent field: A virtual field of an entity bean with container-managed persistence; it is stored in a database.

Relationship field: A virtual field of an entity bean with container-managed persistence; it identifies a related entity bean.