 27 | of entity classes and to keep them simple as possible. Retrieval by Class and Primary Key Every entity object can be uniquely identified and retrieved by the combination of its class and its primary key ... whose primary key is 1:
Employee employee = em.find(Employee.class, 1);
Casting of the retrieved |
27 | for persistent fields, how to define and use a primary key and what a version field is and how to use it. If you are already familiar with JPA you might have noticed that the Point entity class has no primary key ... defined primary key is not required. On the other hand, ObjectDB also supports explicit JPA primary |
27 | for persistent fields, how to define and use a primary key and what a version field is and how to use it. If you are already familiar with JPA you might have noticed that the Point entity class has no primary key ... defined primary key is not required. On the other hand, ObjectDB also supports explicit JPA primary |
27 | , how to define and use a primary key and what a version field is and how to use it. If you are already familiar with JPA you might have noticed that the Point entity class has no primary key (@Id) field defined. As an object database, ObjectDB supports implicit object IDs, so an explicitly defined primary key |
27 | , how to define and use a primary key and what a version field is and how to use it. If you are already familiar with JPA you might have noticed that the Point entity class has no primary key (@Id) field defined. As an object database, ObjectDB supports implicit object IDs, so an explicitly defined primary key |
27 | , how to define and use a primary key and what a version field is and how to use it. If you are already familiar with JPA you might have noticed that the Point entity class has no primary key (@Id) field defined. As an object database, ObjectDB supports implicit object IDs, so an explicitly defined primary key |
27 | , how to define and use a primary key and what a version field is and how to use it. If you are already familiar with JPA you might have noticed that the Point entity class has no primary key (@Id) field defined. As an object database, ObjectDB supports implicit object IDs, so an explicitly defined primary key |
27 | (Mapped By) fields Primary key (ID) fields Version field The first three groups (transient, persistent ... two groups (primary key and version fields) can only be used in entity classes. Primary key fields are discussed in the Primary Key section. Transient Fields Transient entity fields are fields |
26 | field (similar to how primary keys behave). @Index represents either an ordinary index ... can only be defined on ordinary persistent fields (not on primary key / version fields). Composite Index A composite ... the BTree's primary sort key and which field is used as a secondary sort key. If x is specified first |
25 | javax.jdo.annotations Annotation Key Target: Fields (including property get methods) Annotation for the key of a map relation. Corresponds to the xml element "key". Since: JDO 2.1 String column Name of the column to store the key in. Name of the column to store the key in. Returns: name |