Relation Mapping

Relation Mapping EJB 3.0 コース第9回

ここでの目標 • 複数のテーブルを組み合わせてデータにアクセスする「Relation Mapping」について理解する

@OneToOne Annotation

一対一の関係の例：自宅は一つ EJB_EMPLOYEE　社員テーブル EJB_ADDRESS　住所テーブル

EJB_EMPLOYEE　社員テーブル @Entity @Table(name="EJB_EMPLOYEE") public class Employee implements Serializable {…… @Id @Column(name="EMP_ID", primaryKey=true) public Integer getId() { return id; } …… @Version @Column(name="VERSION") public int getVersion() { return version; } …… @Column(name="L_NAME", length=80) public String getLastName() { return lastName; } …… @Column(name=“F_NAME", length=80) public String geFirstName() { return firstName; } …… @OneToOne(cascade=ALL, fetch=LAZY) @JoinColumn(name="ADDR_ID") public Address getAddress() { return address; } …… }

EJB_ADDRESS　住所テーブル @Entity @Table(name="EJB_ADDRESS") public class Address implements Serializable {….. @Id @Column(name="ADDRESS_ID", primaryKey=true) public Integer getId() { return id; } …. public void setId(Integer id) { this.id = id; } public String getStreet() { return street; } public void setStreet(String street) { this.street = street; } public String getCity() { return city; } public void setCity(String city) { this.city = city; } public String getProvince() { return province; } public void setProvince(String province) { this.province = province; } @Column(name="P_CODE") public String getPostalCode() { return postalCode; }…. public String getCountry() { return country; } public void setCountry(String country) { this.country = country; } } Default名

社員のアドレスの取得 public Address getAddressForEmployee(Integer employeeId) { Employee employee = (Employee)em .find("Employee", employeeId); return employee.getAddress(); } public void setAddressForEmployee (Address address, Integer employeeId) { em.persist(address); Employee employee = (Employee)em.find("Employee", employeeId); employee.setAddress(address); } public void updateAddress(Address addressExample) { em.find("Address", addressExample.getId()); em.merge(addressExample); }

@ManyToOne Annotation

多対一の関係の例：複数の社員が一人の上司を持つ多対一の関係の例：複数の社員が一人の上司を持つ EJB_EMPLOYEE　社員テーブル EJB_EMPLOYEE　社員テーブル

EJB_EMPLOYEE　社員テーブル @Entity @Table(name="EJB_EMPLOYEE") public class Employee implements Serializable {…… @Id @Column(name="EMP_ID", primaryKey=true) public Integer getId() { return id; } …… @Version @Column(name="VERSION") public int getVersion() { return version; } …… @Column(name="L_NAME", length=80) public String getLastName() { return lastName; } …… @Column(name=“F_NAME", length=80) public String geFirstName() { return firstName; } …… @OneToOne @JoinColumn(name="ADDR_ID") public Address getAddress() { return address; } …… @ManyToOne(cascade=PERSIST, fetch=LAZY) @JoinColumn(name="MANAGER_ID",referencedColumnName="EMP_ID") public Employee getManager() { return manager; } …… }

社員の上司の取得 public Employee getManagerForEmployee(Integer employeeId) { Employee employee = (Employee)em.find("Employee", employeeId); Employee manager = employee.getManager(); if (manager != null) { manager.getAddress(); manager.getManager(); } return manager; }

@OneToMany Annotation

一対多の関係の例：一人が複数の部下を持つ EJB_EMPLOYEE　社員テーブル EJB_EMPLOYEE　社員テーブル

@OneToMany @JoinColumn(name="MANAGER_ID", referencedColumnName="EMP_ID") public Collection<Employee>getManagedEmployees() { return managedEmployees; } 社員の部下（複数）の取得 public Collection getManagedEmployeesForEmployee(Integer employeeId) { Employee employee = (Employee)em.find("Employee", employeeId); Collection employees = employee.getManagedEmployees(); Iterator employeeIterator = employees.iterator(); while (employeeIterator.hasNext()) { Employee mEmployee = (Employee)employeeIterator.next(); mEmployee.getAddress(); mEmployee.getManager(); } return employees; }

一対多の関係の例：一人が複数の電話を持つ EJB_EMPLOYEE　社員テーブル EJB_PHONENUMBER　電話番号テーブル

EJB_PHONENUMBER　電話番号テーブル @Entity @Table(name="EJB_PHONENUMBER") public class PhoneNumber implements Serializable { @Id @Column(name="ID", primaryKey=true) public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } @Column(name="NUMB") public String getNumber() { return number; } public void setNumber(String number) { this.number = numbe} public String getType() { return type; } public void setType(String type) { this.type = type; } @Column(name="AREA_CODE") public String getAreaCode() { return areaCode; } public void setAreaCode(String areaCode) { this.areaCode = areaCode; } @ManyToOne(fetch=LAZY) @JoinColumn(name="OWNER_ID", referencedColumnName="EMP_ID") public Employee getOwner() { return owner; } public void setOwner(Employee owner) { this.owner = owner; } }

EJB_EMPLOYEE　社員テーブル @Entity @Table(name="EJB_EMPLOYEE") public class Employee implements Serializable {…… @Id @Column(name="EMP_ID", primaryKey=true) public Integer getId() { return id; } …… @Version @Column(name="VERSION") public int getVersion() { return version; } …… } …… @OneToOne @JoinColumn(name="ADDR_ID") public Address getAddress() { return address; } …… @ManyToOne @JoinColumn(name="MANAGER_ID",referencedColumnName="EMP_ID") public Employee getManager() { return manager; } @OneToMany(cascade=ALL) @JoinColumn(name="OWNER_ID", referencedColumnName="EMP_ID") public Collection<PhoneNumber> getPhoneNumbers() { return phoneNumbers; } }

社員の電話番号（複数）の取得 public Collection getPhoneNumbersForEmployee(Integer employeeId) { Employee employee = (Employee)em.find("Employee", employeeId); Collection phoneNumbers = employee.getPhoneNumbers(); Iterator pIterator = phoneNumbers.iterator(); while (pIterator.hasNext()) { PhoneNumber pNumber = (PhoneNumber)pIterator.next(); pNumber.getOwner(); } return phoneNumbers; }

@ManyToMany Annotation

EJB_PROJECT　プロジェクトテーブル @Entity @Table(name="EJB_PROJECT") public class Project implements Serializable { @Id @Column(name="PROJ_ID", primaryKey=true) public Integer getId() { return projId; } public void setId(Integer id) { this.projId = id; } @Version @Column(name="VERSION") public int getVersion() { return version; } protected void setVersion(int version) { this.version = version; } @Column(name="PROJ_NAME") public String getName() { return name; } public void setName(String name) { this.name = name; } @Column(name="DESCRIP") public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } @OneToOne(fetch=LAZY) @JoinColumn(name="LEADER_ID") public Employee getTeamLeader() { return teamLeader; } public void setTeamLeader(Employee teamLeader) {…. } }

多対多の関係の例：社員のプロジェクトへの所属多対多の関係の例：社員のプロジェクトへの所属 EJB_PROJ_EMP Association Table

EJB_EMPLOYEE　社員テーブル EJB_PROJECT　プロジェクトテーブル

多対多の関係の表現： Association Table EJB_EMPLOYEE　社員テーブル joinColumns=@JoinColumn(name="EMP_ID", referencedColumnName="EMP_ID"), Association Table EJB_PROJ_EMP inverseJoinColumns=@JoinColumn(name="PROJ_ID", referencedColumnName="PROJ_ID") EJB_PROJECT　プロジェクトテーブル

@ManyToMany(cascade=PERSIST) @AssociationTable(table=@Table(name="EJB_PROJ_EMP"), joinColumns=@JoinColumn(name="EMP_ID", referencedColumnName="EMP_ID"), inverseJoinColumns=@JoinColumn(name="PROJ_ID", referencedColumnName="PROJ_ID") ) public Collection<Project> getProjects() { return projects; } public void setProjects(Collection<Project> projects) { this.projects = projects; } プロジェクトの生成 public void createProject(String name, String description) { Project project= new Project(); project.setName(name); project.setDescription(description); em.persist(project); }

プロジェクトへの社員の追加 public void addEmployeeToProject( Integer employeeId, Integer projectId) { Employee employee = (Employee)em.find("Employee", employeeId); Project project = (Project)em.find("Project", projectId); project.addTeamMember(employee); employee.addProject(project); }

プロジェクト所属の社員の獲得 public Collection getEmployeesForProject(Integer projectId){ Project project = (Project)em.find(“Project”, projectId); Iterator employeeIterator = project.getTeamMembers().iterator(); while (employeeIterator.hasNext()) { Employee employee = (Employee)employeeIterator.next(); employee.getAddress(); employee.getManager(); } return project.getTeamMembers(); }

社員登録の削除 public void removeEmployee(Integer employeeId) { Employee employee = (Employee) em.find("Employee", employeeId); Collection<Project> projects = employee.getProjects(); for (Project project : projects) { project.removeTeamMember(employee); } Collection<Employee> employees = employee.getManagedEmployees(); for (Employee emp : employees) { emp.setManager(null); } Employee manager = employee.getManager(); if (manager != null) { manager.removeManagedEmployee(employee); } em.remove(employee); }

Relation Mapping