@Override
    protected void addChild(JdbcPet root, Visit child) {
        root.addVisit(child);
    }
{@link ResultSetExtractor} implementation by using the
{@link OneToManyResultSetExtractor} of Spring Data Core JDBC Extensions.
src/main/java/org/springframework/samples/petclinic/repository/jdbc/JdbcPetVisitExtractor.java