'How to access many to many relationship auto generated table in Java Spring?
I have two table named recipe and tags, joined with many to many relationship
This is recipe table:
@Data
@NoArgsConstructor
@Entity()
@Table(name = "recipes",
uniqueConstraints = {
@UniqueConstraint(name = "recipe_title_unique", columnNames = "title")
})
public class RecipeEntity {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id", updatable = false)
private Long id;
@ManyToMany(fetch = FetchType.EAGER)
@JoinTable(
joinColumns = @JoinColumn(name = "recipe_id", referencedColumnName = "id"),
inverseJoinColumns = @JoinColumn(name = "tag_id", referencedColumnName = "id")
)
private Set<TagEntity> tags;
And this is tags table:
@Data
@NoArgsConstructor
@Entity()
@Table(name = "tags", uniqueConstraints = {
@UniqueConstraint(name = "tag_unique", columnNames = "name")
})
public class TagEntity {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "id", updatable = false)
private int id;
@Column(name = "name", nullable = false)
private String name;
ERD Diagram for many to many relationship
My question is, how I access recipes_tags table with JPQL?
For example I want to know how many recipe that use tag with ID 1.
@Query(value = "SELECT " +
"COUNT t.tag_id " +
"FROM recipes_tags t +
"WHERE t.tag_id = :tagId")
Int getCount(@Param("tagId") int tagId);
Sources
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Source: Stack Overflow
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