🍃➕🔑 SpringBoot and JPA composite key

Return to site

🍃➕🔑 SpringBoot and JPA composite key

· java

Sometimes you need to use several attributes of an entity to design your DB primary key.

JPA composite key serves that purpose.

Let's see how to implement such composite key !

I used this example

1️⃣ 𝐘𝐨𝐮 𝐝𝐞𝐟𝐢𝐧𝐞 𝐭𝐡𝐞 𝐂𝐨𝐦𝐩𝐨𝐬𝐢𝐭𝐞 𝐊𝐞𝐲🔑 𝐂𝐥𝐚𝐬𝐬 𝐟𝐨𝐫 𝐭𝐡𝐞 𝐢𝐝:

public class 𝐁𝐨𝐨𝐤𝐈𝐝 implements Serializable {

  private String 𝐚𝐮𝐭𝐡𝐨𝐫;
  private String 𝐧𝐚𝐦𝐞;

  // standard getters and setters
}

2️⃣ 𝐘𝐨𝐮 𝐮𝐬𝐞 𝐢𝐭 𝐚𝐬 𝐢𝐝🆔 𝐢𝐧 𝐲𝐨𝐮𝐫 𝐞𝐧𝐭𝐢𝐭𝐲:

@Entity
public class Book {

  @𝐄𝐦𝐛𝐞𝐝𝐝𝐞𝐝𝐈𝐝
  private 𝐁𝐨𝐨𝐤𝐈𝐝 𝐢𝐝;
  private String genre;
  private Integer price;

  //standard getters and setters
}

3️⃣ 𝐘𝐨𝐮 𝐟𝐢𝐧𝐚𝐥𝐥𝐲 𝐦𝐚𝐤𝐞 𝐲𝐨𝐮𝐫 𝐜𝐚𝐥𝐥𝐬📞 𝐭𝐨 𝐭𝐡𝐞 𝐫𝐞𝐩𝐨𝐬𝐢𝐭𝐨𝐫𝐲:

@Repository
public interface BookRepository extends JpaRepository<Book, 𝐁𝐨𝐨𝐤𝐈𝐝> {

  List<Book> findById𝐍𝐚𝐦𝐞(String name);

  List<Book> findById𝐀𝐮𝐭𝐡𝐨𝐫(String author);
}

💡 Example of code where I used it