0 Replies Latest reply on Dec 28, 2012 2:19 AM by Amit Jadhav

    Updating record in Many-to-one relationship

    Amit Jadhav Newbie

      I am trying out a simple example where I have an Employee table and a Department table where Many employees belong to a single department forming a Many to one relationship.

      I have used the seam generated entity classes for both employee and department. I am using my custom EJB3 seam component to populate an employee details and to update them. Populating works file , but when i try to update seam updates the Department table instead of just changing the department number in the employee row. My code is as below.

       

       

          @Entity

          @Table(name = "EMP")

          public class Emp implements java.io.Serializable {

         

              private short empno;

              private Dept dept;

              private String ename;

              private String job;

              private Short mgr;

              private Date hiredate;

              private BigDecimal sal;

              private BigDecimal comm;

         

              public Emp() {

              }

         

              public Emp(short empno) {

                  this.empno = empno;

              }

              public Emp(short empno, Dept dept, String ename, String job, Short mgr,

                      Date hiredate, BigDecimal sal, BigDecimal comm) {

                  this.empno = empno;

                  this.dept = dept;

                  this.ename = ename;

                  this.job = job;

                  this.mgr = mgr;

                  this.hiredate = hiredate;

                  this.sal = sal;

                  this.comm = comm;

              }

         

              @Id

              @Column(name = "EMPNO", unique = true, nullable = false, precision = 4, scale = 0)

              public short getEmpno() {

                  return this.empno;

              }

         

              public void setEmpno(short empno) {

                  this.empno = empno;

              }

         

              @ManyToOne(fetch = FetchType.LAZY)

              @JoinColumn(name = "DEPTNO")

              public Dept getDept() {

                  return this.dept;

              }

         

              public void setDept(Dept dept) {

                  this.dept = dept;

              }

         

              @Column(name = "ENAME", length = 10)

              @Length(max = 10)

              public String getEname() {

                  return this.ename;

              }

         

              public void setEname(String ename) {

                  this.ename = ename;

              }

         

              @Column(name = "JOB", length = 9)

              @Length(max = 9)

              public String getJob() {

                  return this.job;

              }

         

              public void setJob(String job) {

                  this.job = job;

              }

         

              @Column(name = "MGR", precision = 4, scale = 0)

              public Short getMgr() {

                  return this.mgr;

              }

         

              public void setMgr(Short mgr) {

                  this.mgr = mgr;

              }

         

              @Temporal(TemporalType.DATE)

              @Column(name = "HIREDATE", length = 7)

              public Date getHiredate() {

                  return this.hiredate;

              }

         

              public void setHiredate(Date hiredate) {

                  this.hiredate = hiredate;

              }

         

              @Column(name = "SAL", precision = 7)

              public BigDecimal getSal() {

                  return this.sal;

              }

         

              public void setSal(BigDecimal sal) {

                  this.sal = sal;

              }

         

              @Column(name = "COMM", precision = 7)

              public BigDecimal getComm() {

                  return this.comm;

              }

         

              public void setComm(BigDecimal comm) {

                  this.comm = comm;

              }

         

          }

       

       

      The department looks like

       

          @Entity

          @Table(name = "DEPT")

          public class Dept implements java.io.Serializable {

         

              private int deptno;

              private String dname;

              private String loc;

              private Set<Emp> emps = new HashSet<Emp>(0);

         

              public Dept() {

              }

         

              public Dept(int deptno) {

                  this.deptno = deptno;

              }

              public Dept(int deptno, String dname, String loc, Set<Emp> emps) {

                  this.deptno = deptno;

                  this.dname = dname;

                  this.loc = loc;

                  //this.emps = emps;

              }

         

              @Id

              @OneToMany

              @Column(name = "DEPTNO", unique = true, nullable = false, precision = 2, scale = 0)

              public int getDeptno() {

                  return this.deptno;

              }

         

              public void setDeptno(int deptno) {

                  this.deptno = deptno;

              }

         

              @Column(name = "DNAME", length = 14)

              @Length(max = 14)

              public String getDname() {

                  return this.dname;

              }

         

              public void setDname(String dname) {

                  this.dname = dname;

              }

         

              @Column(name = "LOC", length = 13)

              @Length(max = 13)

              public String getLoc() {

                  return this.loc;

              }

         

              public void setLoc(String loc) {

                  this.loc = loc;

              }

         

              @OneToMany(fetch = FetchType.LAZY, mappedBy = "dept")

              public Set<Emp> getEmps() {

                  return this.emps;

              }

         

              public void setEmps(Set<Emp> emps) {

                  this.emps = emps;

              }

         

          }

       

       

      And my EJB3 looks like

       

       

          @Stateful

          @Name("workflow")

          @Scope(ScopeType.CONVERSATION)

          public class WorkflowBean implements Workflow

          {

              @Logger private Log log;

         

              @In StatusMessages statusMessages;

             

             

              @PersistenceContext(type=PersistenceContextType.EXTENDED)

              EntityManager entityManager;

                   

             

             @Out(required=false)

              Emp employee = new Emp();

            

              @RequestParameter("empEmpno")

              String empNo;

             

         

              public void workflow()

              {

                 

                  log.info("workflow.workflow() action called");

                  statusMessages.add("workflow");

                 

              }

              @End

              public boolean save(){

                  entityManager.setFlushMode(FlushModeType.COMMIT);

                  System.out.println("In Save---"+empNo);

              try{   

              Dept dept = employee.getDept();

              String deptName= dept.getDname();

              System.out.println("The Dept Name--- "+deptName);

              List<Emp> empList = entityManager.createQuery("SELECT e FROM Emp e WHERE e.empno=:empno").setParameter("empno", employee.getEmpno()).getResultList();

              employee=empList.get(0);

             

             Integer deptNo = (Integer) entityManager.createQuery("SELECT d.deptno FROM Dept d WHERE d.dname=:dname").setParameter("dname", deptName).getSingleResult();

                  Dept newDept = new Dept();

                  newDept = entityManager.find(Dept.class, deptNo.intValue());

             employee.setDept(newDept);

              entityManager.merge(employee);

                 

              return true;

              }catch(Exception e){

                  return false;

              }

              }

              @Begin(join=true)

              public boolean populateEmp(){

                  entityManager.setFlushMode(FlushModeType.COMMIT);

                  System.out.println("The Emp No. is---"+empNo);

                  int no = Integer.parseInt(empNo);

                  short emp =(short)no;

                  employee = entityManager.find(Emp.class, emp);

                  entityManager.flush();

                  return true;

              }

              public Emp getEmployee() {

                  return employee;

              }

         

              public void setEmployee(Emp employee) {

                  this.employee = employee;

              }

              // add additional action methods

             

              public String getEmpNo() {

                  return empNo;

              }

         

              public void setEmpNo(String empNo) {

                  this.empNo = empNo;

              }

              @Remove

              @Destroy

              public void destroy() {

         

              }

          }

       

      Before doing `entityManager.setFlushMode(FlushModeType.COMMIT);` on each form submit my department entity was directly modified. I solved that but still can wrap my head around why it has to modify the department table. I have just started with Seam