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A JPA Persistence Unit is a logical grouping of user defined persistable classes (entity classes, embeddable classes and mapped superclasses) with related settings. Defining a persistence unit is optional when using ObjectDB, but required by JPA. persistence.xml

The term persistable types refers to data types that can be used for storing data in the database. ObjectDB supports all the JPA persistable types, which are: User defined ... directly. Other persistable types can be embedded in entity classes as

The Java Persistence API (JPA) is a standard API for accessing databases from within Java ... JDBC. Using plain old Java objects (POJO) to represent persistent data can significantly simplify ... support of the Java Persistence API (JPA). By interacting with ObjectDB using standard JPA

javax.persistence.criteria persistence.criteria ... _Expression_" title="Method of javax.persistence.criteria.CriteriaBuilder">abs(

; Other... > Persistence > Entity Class and clicking Next). Enter Finish to generate a default persistence.xml file with a default persistence unit (that will be configured later). If the Finish

; Other... > Persistence > Entity Class and clicking Next). Enter ... and Database] step click Finish to generate a default persistence.xml file with a default persistence unit (that will be configured later). If the Finish button

; import java.sql.Date; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; @Entity public class Guest implements Serializable { private static final long serialVersionUID = 1L; // Persistent Fields: @Id @GeneratedValue Long

.Serializable; import java.sql.Date; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; @Entity public class Guest implements Serializable { private static final long serialVersionUID = 1L; // Persistent Fields: @Id

Persistent Classes are user defined classes whose instances can be stored in a database using JDO. Instances of these classes that represent objects in the database are called persistent objects or persistent instances. Objects that do not represent anything in the database

="It includes the following section:"> 6.1  Making Objects Persistent In JDO applications, every object in memory is either a persistent object, i.e. represents some database ... object, regardless of its type. Instances of persistent classes can become persistent later, as