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When using this annotation you might need to use @JoinTable?

When using this annotation you might need to use @JoinTable?

Most often, you will need to use @JoinTable annotation to specify the mapping of a many-to-many table relationship:

  1. the name of the link table and.
  2. the two Foreign Key columns.

What is @entity annotation in spring?

The @Entity annotation specifies that the class is an entity and is mapped to a database table. The @Table annotation specifies the name of the database table to be used for mapping.

What does the ID annotation in an entity bean signify?

The @Id annotation lets you define which property is the identifier of your entity bean. This property can be set by the application itself or be generated by Hibernate (preferred).

What can be said about the @entity annotation?

@Entity annotation defines that a class can be mapped to a table. And that is it, it is just a marker, like for example Serializable interface.

What is hibernate JoinTable?

Annotation Type JoinTable. @Target(value={METHOD,FIELD}) @Retention(value=RUNTIME) public @interface JoinTable. Used in the mapping of associations. It is specified on the owning side of an association. A join table is typically used in the mapping of many-to-many and unidirectional one-to-many associations.

What is mappedBy?

mappedby=”object of entity of same class created in another class” Note:-Mapped by can be used only in one class because one table must contain foreign key constraint. if mapped by can be applied on both side then it remove foreign key from both table and without foreign key there is no relation b/w two tables.

What is @autowired annotation in Spring boot?

The @Autowired annotation provides more fine-grained control over where and how autowiring should be accomplished. The @Autowired annotation can be used to autowire bean on the setter method just like @Required annotation, constructor, a property or methods with arbitrary names and/or multiple arguments.

What is @data annotation in Spring boot?

@Data is a convenient shortcut annotation that bundles the features of @ToString , @EqualsAndHashCode , @Getter / @Setter and @RequiredArgsConstructor together: In other words, @Data generates all the boilerplate that is normally associated with simple POJOs (Plain Old Java Objects) and beans: getters for all fields.

What is @generated value annotation?

@GeneratedValue: This annotation is used to specify the primary key generation strategy to use. i.e Instructs database to generate a value for this field automatically. If the strategy is not specified by default AUTO will be used.

What is the @bean annotation?

@Bean is a method-level annotation and a direct analog of the XML element. The annotation supports most of the attributes offered by , such as: init-method , destroy-method , autowiring , lazy-init , dependency-check , depends-on and scope .

What is inverseJoinColumns in JPA?

InverseJoinColumn is used to customize the column name in the table of the associated class reference variable name. that column act as a foreign key.

What is cascade type all?

The meaning of CascadeType. ALL is that the persistence will propagate (cascade) all EntityManager operations ( PERSIST, REMOVE, REFRESH, MERGE, DETACH ) to the relating entities. It seems in your case to be a bad idea, as removing an Address would lead to removing the related User .

What is the use of @jointable annotation?

The @JoinTable annotation also lets you customize various aspects of the join table. For example, had we annotated the tasks property like this: Finally, if you want to create a schema for a many-to-many association, using a join table is the only available solution. Show activity on this post.

When to use @jointable in hibernate?

It’s also used for OneToMany (usually unidirectional) associations when you don’t want to add a foreign key in the table of the many side and thus keep it independent of the one side. Search for @JoinTable in the hibernate documentation for explanations and examples.

Which annotation is being used for bidirectional mapping?

In our example for bidirectional mapping OneToMany/OneToOne association is being used. @JoinTable annotation is used to join two table using a third table.

What is the link table called in post comment?

And now, the link table is going to be called post_comment_ref and the Foreign Key columns will be post_id, for the post table, and post_comment_id, for the post_comment table.