Hibernate @OneToMany删除并再次插入

Question

I have an issue using Hibernate 3.6.10.Final.

I have a OneToMany relation mapped using something like this:

public class Master implements Serializable {

    @Id
    @GeneratedValue(strategy = IDENTITY) 
    Long masterId;

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "master")
    private List<Row> rows = new ArrayList<Attribute>(0);

    // Getter and setters and other properties

}

public class Row implements Serializable {
    @EmbeddedId
    @AttributeOverrides({
        @AttributeOverride(
            name = "masterId", 
            column = @Column(name = "masterId", nullable = false)),

        // Index is calculated 
        @AttributeOverride(
            name = "index", 
            column = @Column(name = "index", nullable = false, length = 18))
    })
    @NotNull
    private RowId id;

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "masterId", nullable = false, insertable = false, updatable = false)
    @XmlTransient
    private Master master;

    // Some other properties, getters and setters
}

I'm implementing a saveAll REST Method and the object serialized from the request json is the complete representation of the @OneToMany relation.

I cannot use the hibernate automatic behavior, because Row.RowId.index is calculated using a legacy algorithm.

So, to do that, I perform this operation on create:

@Transactional
public void createAll(Master master) throws Exception {

    // Save in a variable the row list
    List<Row> rows = master.getRows();

    // Nullify the rows
    master.setRows(null);

    // Persists the Master using an helper
    masterService.persist(master);

    for (Row row : rows) {

        // the row helper method has the legacy index algorithm
        rowService.persist(row);

    }
}

And this works good, inserts are done without issues.

The problem comes on update, when I need to delete each row before to insert. The code is quite the same as insert, but there is a call to the deleteAll that does an HQL update Query.

@Transactional
public void updateAll(Master master) throws Exception {

    // Save in a variable the row list
    List<Row> rows = master.getRows();

    // Nullify the rows
    master.setRows(null);

    // Persists the Master using an helper
    masterService.merge(master);

    // Delete Everything before to save
    rowService.deleteAll(master);

    for (Row row : rows) {
        rowService.persist(row);
    }
}

This only works when there where no rows before this update. When there are rows, hibernate delete everything, insert the new rows without errors, but does not persists them to database.

The result is to clear all the current master rows.

Is there a way to avoid this issue in a clear way? I don't what to do that using SQL I don't want to mix them...

Thanks a lot, Davide.

Answer 1

@OneToMany relation has a cascade type set to any. This tells to Hibernate to synchronize changes to child.

Removing the cascadeType, everything works fine.

public class Master implements Serializable {

    @Id
    @GeneratedValue(strategy = IDENTITY) 
    Long masterId;

    @OneToMany(fetch = FetchType.LAZY, mappedBy = "master")
    private List<Row> rows = new ArrayList<Attribute>(0);

    // Getter and setters and other properties

}

Thanks a lot, Davide.