We need a domain model object to map the records that are inserted into our database. To do this, we will use the JPA specification; so, we will create an entity class for this purpose:

1. Let's create a new Java package, to store it, and name it model. The fully qualified package name will be com.packtpub.thorntail.footballmanagermicroservice.model.
2. After that, we will build the domain class, named FootballManager (only the fields section is shown here):

...

   /**
    * Domain model class that maps the data stored into football_manager table
    * inside database.
    *
    * @author Mauro Vocale
    * @version 1.0.0 19/08/2018
    */

   @Entity
   @Table(name = "FOOTBALL_MANAGER")
   @XmlRootElement
   @NamedQueries({
    @NamedQuery(name = "FootballManager.findAll", query
             = "SELECT f FROM FootballManager f")
    })
   public class FootballManager {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Basic(optional = false)
    @Column(name = "ID")
    private Long id;

    @Basic(optional = false)
    @NotNull
    @Size(min = 1, max = 50)
    @Column(name = "NAME")
    private String name;

    @Basic(optional = false)
    @NotNull
    @Size(min = 1, max = 50)
    @Column(name = "SURNAME")
    private String surname;

    @Basic(optional = false)
    @NotNull
    @Column(name = "AGE")
    private int age;

    @Basic(optional = false)
    @NotNull
    @Size(min = 1, max = 50)
    @Column(name = "NICKNAME")
    private String nickname;

    ...

   }

3. To complete the management of database access operations, we need to configure the persistence.xml file, inside the src/main/resources/META-INF directory, where we will store all of the configurations related to our persistence layer. Remember to set:
   
   • The name of the persistence unit (FootballManagerPU)
   • The transaction type (JTA), which means that we demand to the container the management of the transactions
   • The data source JNDI name to use (java:/jboss/datasources/FootballManagerDS)
   • The load script source that will preload a subset of data into the database

4. Finally, we will create the default project (the defaults.yml file) in the src/main/resources/ directory, where we will define the data source, FootballManagerDS, that contains the configuration to connect to the database:

swarm:
     datasources:
    data-sources:
      FootballManagerDS:
             driver-name: mysql
             connection-url: jdbc:mysql://localhost:3306/football_managers_registry
             user-name: root
             password: root
             valid-connection-checker-class-name: org.jboss.jca.adapters.jdbc.extensions.mysql.MySQLValidConnectionChecker
             validate-on-match: true
             background-validation: false
             exception-sorter-class-name: org.jboss.jca.adapters.jdbc.extensions.mysql.MySQLExceptionSorter

5. Let's complete the process by setting the relative dependency to io.thorntail.datasources and the mysql driver in the Maven pom.xml file.
6. Declaring the vendor JDBC library dependency, Thorntail will automatically detect and install the driver.