Library3: API Rest Library Book @ManyToMany @OneToOne CRUD with Swagger

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Spring Boot Projects: Library3

Base project

• Base project:
  • POM
  • API REST Book
  • DataBase H2: Library2
    • First-time CREATE DDL : First-time CREATE DDL option (after that UPDATE) in application.properties
  • Application.properties
  • Command Line Runner with methods to test
  • Swagger: URL swagger : http://localhost:8080/swagger-ui.html
  • @Entity, @RestController, @Service, @CrudRepository JPA 2.0, @Component

New tools

• Library and Address @Entity

• 1:1 relationship

• n:m relationship: inverse-side or owning-side

  • Every @ManyToMany association has two sides and a join table:
    • the owning side
    • the join table for the relationship created
      • the join table must be specified on the owning side.
    • and the non-owning, or inverse, side.
  • If the association is bidirectional, either side may be designated as the owning side.
  • If the relationship is (not) bidirectional, the non-owning side must use the mappedBy element of the @ManyToMany annotation to specify the relationship field or property of the owning side.

• Annotations:

  • @OneToOne
  • @ManyToMany
  • @JoinTable

• Example @ManyToMany bidirectional:

     @Entity
     public class User{
  
     @ManyToMany
     @JoinTable(name = "USER_PRODUCT"
            joinColumns = @JoinColumn(name = "USER_FK"),
            inverseJoinColumns = @JoinColumn(name = "PRODUCT_FK"))
     public Set<Product> products
  
  
  
  
     @Entity
     public class Product {
  
     @ManyToMany
     @JoinTable(name = "USER_PRODUCT"
           joinColumns = @JoinColumn(name = "PRODUCT_FK"),
           inverseJoinColumns = @JoinColumn(name = "USER_FK"))
     public Set<User> users
  

• Example @ManyToMany unidirectional:

      @Entity
      public class User{
      
      }
   
      @Entity
      public class Product {
  
      @ManyToMany
      @JoinTable(name = "USER_PRODUCT"
            joinColumns = @JoinColumn(name = "PRODUCT_FK"),
            inverseJoinColumns = @JoinColumn(name = "USER_FK"))
      public Set<User> users
  

• Example @OneToOne bidirectional:

     @Entity
     public class Library{
      
     @OneToOne(mappedBy = "address", cascade = CascadeType.ALL)
     private Address address;
  
  
  
     @Entity
     public class Address{
  
     @OneToOne(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
     @JoinColumn(name = "LIBRARY_FK", nullable = false)
     private Library library;
  

Versions

• version 1.0 : basic project:

  • Library, Address and Book @Entity without basic CRUD operations (Read and Create)
  • without assigning Library <n:m> Book and Library <1:1> Address
  • H2 : library3 created
  • included swagger

• version 2.0 : test (JUnit, unitary test) basic project creating:

  1. tables (DDL create and update)
  2. objects and
  3. assign Library <n:m> Book bidirectional by LIBRARY_BOOK_JOIN_TABLE
  4. @ManyToMany Library <n:m> Book bidirectional by LIBRARY_BOOK_JOIN_TABLE