Annotates the class as an entity bean.

See the basic property tutorial and the basic field tutorial for an introduction.

Attribute	Meaning	default
name	The name of the bean	The class name (unqualified)
entityType	container-managed (CMP) or bean-managed (BMP).	CMP
access	FIELD or PROPERTY	PROPERTY
version	The EJB version	3

An access type of PROPERTY uses bean-style setters and getters to implement CMP, i.e. each field Foo will have a getFoo and a setFoo method. The basic property tutorial describes this access type.

An access type of FIELD modifies the Java fields directly to impement CMP like JDO. The basic field tutorial describes this access type.

@Target(TYPE) @Retention(RUNTIME) public @interface Entity { String name() default ""; EntityType entityType() default CMP; AccessType access() default PROPERTY; int version() default 3; }

Specifies a secondary database table for an entity bean. The secondary table will contain the fields with a secondaryTable in the @Column.

Attribute	Meaning	default
name	The name of the table	The unqualified class name.
catalog	the table's catalog	none
schema	the table's schema	none
join	join column to the primary table	joins the primary key
uniqueConstraint	unique constraints during generation	none

@Target(TYPE) @Retention(RUNTIME) public @interface SecondaryTable { String name() default ""; String catalog() default ""; String schema() default ""; JoinColumn []join() default {}; UniqueConstraint []uniqueConstraints() default {}; }

Specifies the database table for an entity bean. The default table name is the class name.

Attribute	Meaning	default
name	The name of the table	The unqualified class name.
catalog	the table's catalog	none
schema	the table's schema	none
uniqueConstraint	unique constraints during generation	none

@Target(TYPE) @Retention(RUNTIME) public @interface Table { String name() default ""; String catalog() default ""; String schema() default ""; UniqueConstraint []uniqueConstraints() default {}; }

Marks a field as a persistent field.

Attribute	Meaning	default
fetch	EAGER or LAZY fetching	FetchType.EAGER

The fetch types are:

• EAGER - fetch the field when the bean is loaded
• LAZY - fetch the field only when the field is used

String property

@javax.ejb.Entity public class Course { @javax.ejb.Basic public String getName() ... }

Lazy-loaded property

@javax.ejb.Entity public class Course { @javax.ejb.Basic(fetch=FetchType.LAZY) public String getMassiveText() ... }

javax.ejb.Basic

@Target({Method, FIELD}) @Retention(RUNTIME) public @interface Basic { FetchType fetch() default EAGER; }

Specifies the field's SQL column name as well as any CREATE TABLE properties for auto generation.

Attribute	Meaning	default
name	The SQL name of the column	the field name
primaryKey	True for primary key	false
unique	True for UNIQUE columns	false
nullable	False for IS NOT NULL columns	true
insertable	True if column is inserted on a create call	true
updatable	True if column is updated when the field is modified	false
columnDefinition	SQL to create the column in a CREATE TABLE	none
secondaryTable	specified if column is stored in a secondary table	none
length	the default length for a VARCHAR for a CREATE TABLE	255
precision	the default length for a number definition for a CREATE TABLE	0
scale	the default length for a number definition for a CREATE TABLE	0

String property

@javax.ejb.Entity public class Course { @javax.ejb.Basic @javax.ejb.Column(unique=true, nullable=false, length=32) public String getName() ... }

javax.ejb.Column

@Target({Method, FIELD}) @Retention(RUNTIME) public @interface Column { String name() default ""; boolean primaryKey() default false; boolean unique() default false; boolean nullable() default true; boolean insertable() default true; boolean updateable() default true; String columnDefinition() default ""; String secondaryTable() default ""; int length() default 255; int precision() default 0; int scale() default 0; boolean specified() default true; }

Marks a field as a primary key. The @Id may specify a generator for automatic key generation when new objects are created.

The default column name is "ID".

Attribute	Meaning	default
generate	The auto-generation type	NONE
generator	The sequence or table generator name	${table}_cseq

The generator types are:

• NONE - no auto generation for this field
• IDENTITY - the database supplies the new key, e.g. auto_increment, SERIAL, or IDENTITY
• SEQUENCE - use a SEQUENCE type to generate the key
• TABLE - use a @TableGenerator for the key
• AUTO - choose the generator based on the database
  • MySQL - IDENTITY using auto_increment
  • Resin - IDENTITY using auto_increment
  • Postgres - SEQUENCE
  • Oracle - SEQUENCE

For SEQUENCE and TABLE, Resin will create the sequence name as "${table}_cseq".

automatic generation

@javax.ejb.Entity public class Course { @javax.ejb.Id(generate=GeneratorType.AUTO) public long getId() ... }

sequence generation

@javax.ejb.Entity public class Course { @javax.ejb.Id(generate=GeneratorType.SEQUENCE, generator=COURSE_SEQ) public long getId() ... }

javax.ejb.Id

@Target({METHOD, FIELD}) @Retention(RUNTIME) public @interface Id { GeneratorType generate() default NONE; String generator() default ""; }

Defines an association table for a many-to-many relation.

Attribute	Meaning	default
table	Table definition for the association table	concatening the source and target table names
joinColumns	Columns from from the association table to the source table	Uses the source table primary key
inverseJoinColumns	Columns from from the association table to the target table	Uses the target table primary key

javax.ejb.AssociationTable

@Target({METHOD, FIELD}) @Retention(RUNTIME) public @interface AssociationTable { Table table() default @Table(specified=false); JoinColumn []joinColumns() default {}; JoinColumn []inverseJoinColumns() default {}; }

Defines a join (foreign) columns. Used for @ManyToOne.

See also @Column for corresponding definition for @Basic columns.

See the Many-to-One tutorial for a full example.

Attribute	Meaning	default
name	The column name of the source table	the column name of the target key
referencedColumnName	The target column for composite keys	the single primary key
primaryKey	True for a primary key	false
unique	True if unique	false
nullable	False if IS NOT NULL	true
insertable	True if the column is inserted on a create	true
updateable	True if the column is updated on field changes	true
columnDefinition	SQL column definition	false
secondaryTable	specifies a secondary table if not in the primary	none

Student to House link

public class Student { @Id @Column(name="student_id") long getId() @ManyToOne @JoinColumn(name="house_id") public House getHouse() }

Student SQL

CREATE TABLE Student { student_id BIGINT PRIMARY KEY auto_increment house_id BIGINT REFERENCES House(id) )

javax.ejb.JoinColumn

@Target({TYPE, METHOD, FIELD}) @Retention(RUNTIME) public @interface JoinColumn { String name() default ""; String referencedColumnName() default ""; boolean primaryKey() default false; boolean unique() default false; boolean nullable() default false; boolean insertable() default true; boolean updateable() default true; String columnDefinition() default ""; String secondaryTable() default ""; }

Defines a set of join (foreign) columns for composite keys.

@Target({TYPE,METHOD, FIELD})
@Retention(RUNTIME)
public @interface JoinColumns {
  JoinColumn [] value() default{}
}

Marks a field as a many-to-many (association) relation.

The column names are the key columns of the source and target tables.

See the many-to-many tutorial for an example.

Attribute	Meaning	default
targetEntity	The class of the target entity	the property's type
cascade	Operations which cascade to the target	none
fetch	EAGER or LAZY fetching	FetchType.EAGER
isInverse	If true, this is the dependent size	false

Simple link

@javax.ejb.Entity public class Student { @javax.ejb.ManyToMany @javax.ejb.AssociationTable( table=@javax.ejb.Table(name="student_course_map"), joinColumns=@JoinColumn(name="student_id"), inverseJoinColumns=@JoinColumn(name="course_id") ) public Collection getCourses() ... }

javax.ejb.ManyToMany

@Target({METHOD, FIELD}) @Retention(RUNTIME) public @interface ManyToMany { String targetEntity default ""; CascadeType []cascade() default {}; FetchType fetch() default LAZY; boolean isInverse() default false; }

Marks a field as a many-to-one (link) relation.

The default column name is the column name of the target key.

See the many-to-one tutorial for an example.

Attribute	Meaning	default
targetEntity	The class of the target entity	the property's type
cascade	Operations which cascade to the target	none
fetch	EAGER or LAZY fetching	FetchType.EAGER
optional	If false, the relation must always have a value	true

Simple link

@javax.ejb.Entity public class Student { @javax.ejb.ManyToOne @javax.ejb.JoinColumn(name="house") public House getHouse() ... }

javax.ejb.ManyToOne

@Target({Method, FIELD}) @Retention(RUNTIME) public @interface ManyToOne { String targetEntity default ""; CascadeType []cascade() default {}; FetchType fetch() default EAGER; boolean optional() default true; }

Marks a field as a one-to-many (collection) relation. Because a one-to-many field is dependent, it needs a @ManyToOne relation on the source table which defines the column.

Attribute	Meaning	default
targetEntity	The class of the target entity	the property's type
cascade	Operations which cascade to the target	none
fetch	EAGER or LAZY fetching	FetchType.EAGER

Collection java

@javax.ejb.Entity public class House { ... @javax.ejb.OneToMany(targetEntity="Student") public Collection getStudents() } @javax.ejb.Entity public class Student { ... @javax.ejb.ManyToOne @javax.ejb.JoinColumn(name="house") public House getHouse() }

Collection SQL

CREATE TABLE House { id BIGINT PRIMARY KEY ) CREATE TABLE Student { id BIGINT PRIMARY KEY, house BIGINT REFERENCES House(id) )

javax.ejb.OneToMany

@Target({METHOD, FIELD}) @Retention(RUNTIME) public @interface OneToMany { String targetEntity default ""; CascadeType []cascade() default {}; FetchType fetch() default EAGER; }

Marks a field as a one-to-one (dependent link) relation. Because a one-to-one field is dependent, it needs a @OneToOne relation on the source table which defines the column.

Attribute	Meaning	default
targetEntity	The class of the target entity	the property's type
cascade	Operations which cascade to the target	none
fetch	EAGER or LAZY fetching	FetchType.EAGER

javax.ejb.OneToOne

@Target({METHOD, FIELD}) @Retention(RUNTIME) public @interface OneToOne { String targetEntity default ""; CascadeType []cascade() default {}; FetchType fetch() default EAGER; boolean optional() default true; }

Configures the discriminator column.

@Target(TYPE)
@Retention(RUNTIME)
public @interface DiscriminatorColumn {
  String name() default "";
  boolean nullable() default false;
  String columnDefinition() default "";
  int length() default 10;
}

@Inheritance marks the entity bean as supporting inheritance, i.e. the database maps to different Java classes depending on a discriminator value.

@Target(TYPE)
@Retention(RUNTIME)
public @interface Inheritance {
  InteritanceType strategy() default SINGLE_TABLE;
  DiscriminatorType discriminatorType() default STRING;
  String discriminatorValue() default "";
}