Question

I am using JPA (Hibernate) to store an entity on a MySQL 5.0 server.

Here is the entity in simplified form:

@Entity
@Table(name = "messages")
public class Message implements Serializable
{
    @Id
    @GeneratedValue
    @Column
    private long id;

    @Column
    private String content;

    @Column(insertable = false)
    private Date read;

    @Column(insertable = false)
    private Date deleted;
}

The columns “read” and “deleted” in table “messages” are defined so that they can contain NULL values. When I first tried to persist one of these entities I got an exception. Apparently, what Hibernate was doing there was listing the “read” and “deleted” columns in the column list of the insert statement but not in the value list. I got around that problem with the “insertable = false” statement in the @Column annotations you see above.

Now, however, I have a bigger problem. I want to set the read or date fields to non-null values. When I do that, I get a similar exception “You have an error in your SQL syntax”. What he is doing now is listing all fields in the where part of the update statement, including “read” and “deleted”. And what he does is check like “…and read=NULL”. Which, in MySQL, of course should be “…and read IS NULL”.

Rummaging around, I already found the “updatable” parameter for the @Column annotation. But if I set that to false, both “read” and “deleted” are never updated at all, so that is not what I am looking for, either.

…Help?

Answer 1

read is a reserved word in mysql and it looks like the driver is not escaping the name with back quotes. I think the best solution is to rename the column.