Classes
@Entity
Specifies that the class is an Entity. Defaults to the name of the entity class, but can be overridden using the optional name element.
@Entity
public class Student {
}
// Override the name of the entity
@Entity(name = "Customer")
public class Person {
}
@Table
Specifies the db table associated with the entity class. The table name defaults to the name of the entity, but can be overridden using name.
@Entity
@Table(name = "students")
public class Student {
}
Properties
@Id
Specifies the primary key of an entity.
@Entity
public class Student {
@Id
private Long id;
}
@Column
Specifies the mapped column for a persistent property or field. Optional elements include name, nullable, unique, length and more.
@Entity
public class Student {
@Column(name = "first_name", length = 55)
private String firstName;
@Column(nullable = false, unique = true)
private String email;
}
@Transient
Specifies that the property or field is not persistent.
@Entity
public class Student {
private Long id;
private String email;
@Transient
private Integer age;
}
@GeneratedValue
Specifies the generation strategies for the values of primary keys. Should be used in conjunction with the @Id annotation and usually paired with @SequenceGenerator.
@Entity
public class Student {
@Id
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "CUSTOM_SEQUENCE")
private Long id;
}
@SequenceGenerator
Defines a primary key generator that may be referenced by name when a generator element is specified for the @GeneratedValue annotation. May be specified on the entity class instead of a property.
@Entity
public class Student {
@Id
@SequenceGenerator(name = "stud_seq", sequenceName = "student_sequence", initialValue = 1, allocationSize = 10)
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "stud_seq")
private Long id;
}