java - 通过 hibernate 删除对象并且失败

Question

我无法直接使用 REmover 类删除代码对象...并且它给了我一个错误...但是当我第一次删除用我的代码添加的注释然后删除代码时，它就完成了......还有其他方法可以自动删除代码和代码对象的注释吗？关于...

WARN: SQL Error: 0, SQLState: 23503 Jun 24, 2013 2:25:51 PM org.hibernate.engine.jdbc.spi.SqlExceptionHelper logExceptions ERROR: ERROR: update or delete on table "code" violates foreign key constraint "fk_evs9qdyt93ms7uvl3ud2nwy71" on table "comments" Detail: Key (codeid)=(14) is still referenced from table "comments". org.hibernate.exception.ConstraintViolationException: could not execute statement at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:129) at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49) at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125)

@Entity
public class Userdetails{
@Id
@GeneratedValue
private long userid;
@Column(nullable = false, unique = true)
private String username;
private String password;
private String fname;
private String lname;
private String email;
@OneToMany(targetEntity=Code.class, mappedBy="userdetails")
private List<Code> codes;
@OneToMany(targetEntity=Messages.class, mappedBy="SMS")
private List<Messages> messages;

public List<Messages> getMessages() {
    return messages;
}
public void setMessages(List<Messages> messages) {
    this.messages = messages;
}
public String getUsername() {
    return username;
}
public void setUsername(String username) {
    this.username = username;
}
public String getPassword() {
    return password;
}
public void setPassword(String password) {
    this.password = password;
}
public String getFname() {
    return fname;
}
public void setFname(String fname) {
    this.fname = fname;
}
public String getLname() {
    return lname;
}
public void setLname(String lname) {
    this.lname = lname;
}
public String getEmail() {
    return email;
}
public void setEmail(String email) {
    this.email = email;
}

public List<Code> getCodes() {
    return codes;
}
public void setCodes(List<Code> codes) {
    this.codes = codes;
}

public Userdetails(String username, String password, String fname, String lname,     String email) {
    super();
    this.username = username;
    this.password = password;
    this.fname = fname;
    this.lname = lname;
    this.email = email;
}
public Userdetails() {
    super();
}
public static boolean updateUserDetails(Object current) {
    return UserDBHandler.updateObject(current);
}
public static boolean setUserDetails(Userdetails user) {
    return UserDBHandler.saveObject(user);
}
public static Userdetails getUserDetails(String username, String password) {
    return UserDBHandler.loadUser(username, password);
}
public static boolean isUser(String username,String passw0rd) {
    return UserDBHandler.isUser(username,passw0rd);
}
public static boolean LogoutUser() {
    return UserDBHandler.LogoutUser();
}


}



package UsersProperty;

@Entity
public class Code {
@Id
@GeneratedValue
private int codeId;
private int Rating;
private int NORaters;
@Column(nullable = false, unique = true)
private String fileName;
private String OwnerName;
private String PrjName;
private String CodeLang;
private String Tags;
    private String Tags2;
@ManyToOne()
@JoinColumn(name="userid")
private Userdetails userdetails;
@OneToMany(targetEntity=Comments.class, mappedBy="targetCode")
private List<Comments> cm;

public int getCodeId() {
    return codeId;
}
public void setCodeId(int codeId) {
    this.codeId = codeId;
}
public int getNORaters() {
    return NORaters;
}
public void setNORaters(int nORaters) {
    NORaters = nORaters;
}
public int getRating() {
    return Rating;
}
public void setRating(int rating) {
    Rating = rating;
}

public List<Comments> getCm() {
    return cm;
}
public void setCm(List<Comments> cm) {
    this.cm = cm;
}
public String getFileName() {
    return fileName;
}
public void setFileName(String fileName) {
    this.fileName = fileName;
}

public String getOwnerName() {
    return OwnerName;
}
public void setOwnerName(String ownerName) {
    OwnerName = ownerName;
}

public String getPrjName() {
    return PrjName;
}
public void setPrjName(String prjName) {
    PrjName = prjName;
}

public String getCodeLang() {
    return CodeLang;
}
public void setCodeLang(String codeLang) {
    CodeLang = codeLang;
}
public String getTags() {
    return Tags;
}
public void setTags(String tags) {
    Tags = tags;
}
    public String getTags2() {
    return Tags2;
}
public void setTags2(String tags2) {
    Tags2 = tags2;
}
public Userdetails getUserdetails() {
    return userdetails;
}
public void setUserdetails(Userdetails userdetails) {
    this.userdetails = userdetails;
}
public Code(String fileName, String ownerName, String prjName,String Lang,String     tAgs,String tAgs2) {
    super();
    this.fileName = fileName;
    OwnerName = ownerName;
    PrjName = prjName;
    Tags=tAgs;
            Tags2=tAgs2;
    CodeLang = Lang;
}
public Code() {
    super();
}

public static void CodeSearch(String TAGS){
        SpecificCodeSearchDBHandler.searchCodeTags(TAGS);
}
    public static Code LoadCode(String Path){
    return CodePathLoaderDBHandler.loadCode(Path);
}
public static String FNameExtractor(String FilePath){
    String Fname = null;
    @SuppressWarnings("resource")
    Scanner Reader = new Scanner(FilePath);
    Reader.useDelimiter("/");
    while(Reader.hasNext())
    Fname = Reader.next();
    return Fname;

}
}



package UsersProperty;


@Entity
public class Comments {
@Id
@GeneratedValue
private int cmId;
private String Cm;
private String Cmplacer;
@ManyToOne()
@JoinColumn(name="codeId")
private Code targetCode;

public Comments() {
}

public String getCm() {
    return Cm;
}
public void setCm(String cm) {
    Cm = cm;
}
public String getCmplacer() {
    return Cmplacer;
}
public void setCmplacer(String cmplacer) {
    Cmplacer = cmplacer;
}
public Code getTargetCode() {
    return targetCode;
}
public void setTargetCode(Code targetCode) {
    this.targetCode = targetCode;
}
public Comments(String cm, String cmplacer) {
    super();
    Cm = cm;
    Cmplacer = cmplacer;
}

}




public class REmover {
private static Session scss;
private static SessionFactory sfactory;
static {
    Configuration cfg = new Configuration();
    cfg.addAnnotatedClass(Userdetails.class);
    cfg.addAnnotatedClass(Code.class);
    cfg.addAnnotatedClass(Messages.class);
    cfg.addAnnotatedClass(Comments.class);
    cfg.configure();
    new SchemaExport(cfg);
    sfactory = cfg.buildSessionFactory();

}
public static boolean removeCode(Object object) {
    try {
        scss = sfactory.openSession();
        scss.beginTransaction();
        scss.delete(object);
                    scss.getTransaction().commit();
        return true;
    } catch (Exception e) {
        e.printStackTrace();
        scss.getTransaction().rollback();
    }
    return false;
}

Answer 1

尝试向您的@OneToMany添加适当的级联操作，例如

@OneToMany(targetEntity=Comments.class, mappedBy="targetCode", cascade=CascadeType.REMOVE)

看看API: http://docs.oracle.com/javaee/6/api/javax/persistence/OneToMany.html#cascade()

和:

http://docs.oracle.com/javaee/6/api/javax/persistence/CascadeType.html