New value is inserted into db in @ManyToOne relation instead of update

[Andrej Kurochenko]

Hello everybody,

I'm trying to create CRUD form using Spring FW 3.0.5 and Hibernate 3.4.0. In my web application i have two entities Author and Department in ManyToOne relation. Where one author belongs to one department and one department has many authors. When I add author with some department everything is OK. When I update author Spring is trying to insert new department, not just update it in database. Below are snippets of used code.

@Entity
@Table(name = "author")
public class Author implements Serializable {

    @Id
    @Column(name = "idauthor")
    @GeneratedValue
    private Integer idAuthor;
    
    @Column(name = "me_id")
    private String meId;

    @Column(name = "name")
    private String name;
    
    @Column(name = "surname")
    private String surname;
    
    @Column(name = "note")
    private String note;
    
    @ManyToOne(cascade = CascadeType.ALL)
    private Department department;

    /* getters and setters */
}

@Entity
@Table(name="department")
public class Department implements Serializable {
    
    @Id
    @Column(name="iddepartment")
    @GeneratedValue
    private Integer iddepartment;
    
    @Column(name="name", unique=true)
    private String name;

    /* getters and setters */
}

I've got Formatters, Controllers, AuthorService and DepartmentService interfaces and implementations for handling data operations. Controllers:

@Controller
@RequestMapping("/author")
public class AuthorController {
    
    @Autowired
    private AuthorService authorService;
    
    @Autowired
    private DepartmentService departmentService;
    
    @RequestMapping(method = RequestMethod.GET)
    public String listContacts(Map<String, Object> map) {
 
        map.put("author", new Author());
        map.put("authorList", authorService.listAuthor());
        return "author";
    }
    
    @RequestMapping(value = "/save", method = RequestMethod.POST)
    public String addContact(@ModelAttribute("author") Author author, BindingResult result) {
 
        authorService.saveAuthor(author);
        return "redirect:/author";
    }
    
    @RequestMapping(value = "/save", method= RequestMethod.GET)
    public String renderContact(Model model, @ModelAttribute Author author, WebRequest request) {
 
        model.addAttribute("departmentList", departmentService.listDepartment());        
        return "author.save";
    }

    @RequestMapping(value="/save/{authorId}", method = RequestMethod.GET)
    public String renderUpdateForm(@PathVariable("authorId") Integer authorId, ModelMap model) {
        model.addAttribute("author", authorService.getAuthorByID(authorId));
        
        return "author.save";
    }

    @RequestMapping(value="/save/{authorId}", method = RequestMethod.POST)
    public String updateAuthor(@ModelAttribute("idAuthor") Author author, BindingResult result, SessionStatus status) {
        authorService.updateAuthor(author);
        status.setComplete();
        return "redirect:/author";
    }
    
    @RequestMapping("/delete/{authorId}")
    public String deleteContact(@PathVariable("authorId") Integer authorId) {

        authorService.removeAuthor(authorId);
        return "redirect:/author";
    }
}

@Controller
@RequestMapping("/department")
public class DepartmentController {
    
    @Autowired
    private DepartmentService departmentService;
    
    @RequestMapping(method = RequestMethod.GET)
    public String listContacts(Map<String, Object> map) {
 
        map.put("department", new Department());
        map.put("departmentList", departmentService.listDepartment());
 
        return "department";
    }
    
    @RequestMapping(value = "/save", method = RequestMethod.POST)
    public String addContact(@ModelAttribute("department") Department department, BindingResult result) {
 
        departmentService.saveDepartment(department);
        return "redirect:/department";
    }
    
    @RequestMapping(value = "/save", method= RequestMethod.GET)
    public String renderContact(Model model, @ModelAttribute Department department, WebRequest request) {
 
        return "department.save";
    }

    @RequestMapping(value="/save/{departmentId}", method = RequestMethod.GET)
    public String setupForm(@PathVariable("departmentId") Integer departmentId, ModelMap model) {

        model.addAttribute("department", departmentService.getDepartmentByID(departmentId));        
        return "department.save";
    }

    @RequestMapping(value="/save/{departmentId}", method = RequestMethod.POST)
    public String processSubmit(@ModelAttribute("iddepartment") Department department, BindingResult result, SessionStatus status) {

        departmentService.saveDepartment(department);
        status.setComplete();
        return "redirect:/department";
    }
    
    @RequestMapping("/delete/{departmentId}")
    public String deleteContact(@PathVariable("departmentId") Integer departmentId) {
 
        departmentService.removeDepartment(departmentId);
        return "redirect:/department";
    }
}

And the save.jsp page which contains spring form

<form:form method="post" action="${pageContext.request.contextPath}/author/save" modelAttribute="author">
<form:hidden path="idAuthor" />
 
    <table>
    <tr>
        <td>
            <form:label path="name">
                <spring:message code="label.author.name"/>
            </form:label>
        </td>
        <td><form:input path="name" /></td>
    </tr>
    <tr>
        <td>
            <form:label path="surname">
                <spring:message code="label.author.surname"/>
            </form:label>
        </td>
        <td><form:input path="surname" /></td>
    </tr>
    <tr>
        <td>
            <form:label path="meId">
                <spring:message code="label.author.meid"/>
            </form:label>
        </td>
        <td><form:input path="meId" /></td>
    </tr>
    <tr>
        <td>
            <form:label path="note">
                <spring:message code="label.author.note"/>
            </form:label>
        </td>
        <td><form:input path="note" /></td>
    </tr>
    <tr>
        <td>
            <form:label path="department.name">
                <spring:message code="label.author.department"/>
            </form:label>
        </td>
        <td>
            <form:select path="department.name">
                <c:choose>
                    <c:when test="${ empty departmentList}">
                        <form:option value="" label="Add any department first" disabled="yes"/> 
                    </c:when>
                    <c:otherwise>
                        <form:options items="${departmentList}" itemValue="iddepartment" />
                    </c:otherwise>
                </c:choose>
            </form:select>
        </td>        
    </tr>
    <tr>
        <td colspan="2">
            <c:choose>
                <c:when test="${empty author.idAuthor}">
                    <input type="submit" value="<spring:message code="label.add"/>"/>
                </c:when>
                <c:otherwise>
                    <input type="submit" value="<spring:message code="label.update"/>"/>
                </c:otherwise>
            </c:choose>
        </td>
    </tr>
</table>
</form:form>

When i add an author and then trying to update it (not changing the department) i'm getting an error

com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '1' for key 'name'

Spring is trying to insert same department. But I don't want to insert department, just update. The method which handles insert/update operations of Author entity:

@Repository
public class AuthorDAOImpl implements AuthorDAO {
    
    @Autowired
    private SessionFactory sessionFactory;

    @Override
    public void updateAuthor(Author author) {
        sessionFactory.getCurrentSession().merge(author);
    }

    /* ...  */
}

So I'm asking for your advice and I'll be grateful for any hint of how to update, not insert department. Thanks in advance

[Mark Spritzler]

Moving this to the more appropriate ORM forum for Hibernate.

Mark

[Waswani Naresh]

Hi Andrej,

Could you please answer couple of questions which would probably help me to solve this issue.

In the AuthorDAOImpl's updateAuthor(), where the Author object gets passed...

1) The author has the department object fully populated. From where the department object is retrieved...I mean, before saving the author are you getting the department object in a different query OR it is taken from some list in the memory ?

2) In your scenario, you are not changing the author's department but some other attribute of author ? Is this correct ?

3) Before saving the author, both the department and the author object are in detached mode ? Is this correct ?

Regards,
Naresh Waswani

[Andrej Kurochenko]

Waswani Naresh wrote:
Hi Andrej,

Hello, Waswani
thank you for reply

Waswani Naresh wrote:
In the AuthorDAOImpl's updateAuthor(), where the Author object gets passed...

1) The author has the department object fully populated. From where the department object is retrieved...I mean, before saving the author are you getting the department object in a different query OR it is taken from some list in the memory ?

Well, here I just get Author object in AuthorController and pass it to AuthorService which passes object to aforementioned AuthorDAO. Nothing more is done. I've googled a lot and found very similar issue. So in my case Spring or Hibernate also don't know which department I am trying to update and can't map it to department in database. Maybe I'm passing wrongly list of departments in AuthorController.

Waswani Naresh wrote:
2) In your scenario, you are not changing the author's department but some other attribute of author ? Is this correct ?

Correct. Also my previous code inserted departments ID as name of department, but I've changed line with form:options from

<form:options items="${departmentList}" itemValue="iddepartment" />

to

<form:options items="${departmentList}" itemValue="name" />

Now to reproduce exception I have to load update page and click on button. Exception occurs every time, because all values which are in select are also in database. And I have @Column(name="name", unique=true) to prevent duplicates. I don't need to change department table in database at all, I just need to change departments foreign key in authors table.

Waswani Naresh wrote:
3) Before saving the author, both the department and the author object are in detached mode ? Is this correct ?

I didn't knew what detached mode means so I've googled and found it in hibernate documentation. And as far as I know I'm not doing any detaching unless hibernate does it by itself.