Entity Annotations

Question 1

@Entity

Answer 1

Maps to a table in the database.
@Entity
public class User {
@Id
private Long id;
private String name;
}

Question 2

@Table

Answer 2

Specifies the name of the database table to which an entity is mapped.
@Entity
@Table(name = “users”)
public class User {
@Id
private Long id;
private String name;
}

Question 3

@Id

Answer 3

Marks a field as the primary key of the entity

Question 4

@GeneratedValue

Answer 4

Specifies the strategy for automatically generating primary key values.
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;

Question 5

@Column

Answer 5

Maps a field to a column in the database table.
@Column(name = “user_name”, length = 100, nullable = false)
private String name;

Question 6

@Transient

Answer 6

Marks a field to be ignored by JPA (i.e., not persisted to the database).
@Transient
private String temporaryData;

Question 7

@Version

Answer 7

Used for optimistic locking to manage concurrent updates to the same data.
@Version
private Long version;