EclipseLink seems to be incorrectly passing a null primary key value to Derby when persisting into a table with generated primary key. Derby returns error of Attempt to modify an identity column in this case. Derby needs a SQL statement that excludes the id value. My question is how do I coerce EclipseLink to send the right SQL? Details follow...
I am using Eclipselink to map to a Derby database (v10.8.1.2) under the latest Netbeans 7.3beta2.
The database table primary key is auto generated:
CREATE TABLE STUDENT_BATCH (
ID bigint PRIMARY KEY
GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1),
FILENAME varchar(200) NOT NULL,
SCHOOLBOARD varchar(100) NOT NULL,
CREATE_TS timestamp NOT NULL,
CONTACT_INFO varchar(200),
NOTES varchar(2000),
BOARD_NAME varchar(100)
)
;
The corresponding jpa class specifies that the id is generated using strategy of identity:
@Entity
@Table(name = "STUDENT_BATCH")
@XmlRootElement
@NamedQueries({
@NamedQuery(name = "StudentBatch.findAll", query = "SELECT s FROM StudentBatch s")})
public class StudentBatch implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name = "ID")
private Long id;
@Basic(optional = false)
@Column(name = "FILENAME")
private String filename;
@Basic(optional = false)
@Column(name = "SCHOOLBOARD")
private String schoolboard;
@Basic(optional = false)
@Column(name = "CREATE_TS")
@Temporal(TemporalType.TIMESTAMP)
private Date createTs;
@Column(name = "CONTACT_INFO")
private String contactInfo;
@Column(name = "NOTES")
private String notes;
@Column(name = "BOARD_NAME")
private String boardName;
@OneToMany(cascade = CascadeType.ALL, mappedBy = "studentBatchId")
private Collection<StudentRecord> studentRecordCollection;
methods etc follow...
When I go to persist the class, I do not specify an id so that Derby will provide the id.
StudentBatch sb = new StudentBatch();
sb.setBoardName(meta.get("BOARD NAME"));
sb.setContactInfo(meta.get("CONTACT INFO"));
sb.setCreateTs(new Date());
sb.setFilename(event.getFile().getFileName());
sb.setNotes(meta.get("NOTES"));
sb.setSchoolboard(meta.get("SCHOOL BOARD"));
_logger.debug("persisting batch");
em.persist(sb);
_logger.debug("flushing");
em.flush();
_logger.debug("flushed");
Eclipselink, however, passes the id to derby as null and Derby gives error Attempt to modify an identity column:
INFO: DEBUG 11710 27 Nov 2012 18:17:10,558 [http-thread-pool-8080(4)] (FileUploadController.java:75) - persisting batch
INFO: DEBUG 11713 27 Nov 2012 18:17:10,561 [http-thread-pool-8080(4)] (FileUploadController.java:77) - flushing
WARNING: Local Exception Stack:
Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: java.sql.SQLSyntaxErrorException: Attempt to modify an identity column 'ID'.
Error Code: -1
Call: INSERT INTO STUDENT_BATCH (ID, BOARD_NAME, CONTACT_INFO, CREATE_TS, FILENAME, NOTES, SCHOOLBOARD) VALUES (?, ?, ?, ?, ?, ?, ?)
bind => [7 parameters bound]
Query: InsertObjectQuery(ca.ontario.mhltc.studentupload.model.StudentBatch[ id=null ])
at org.eclipse.persistence.exceptions.DatabaseException.sqlException(DatabaseException.java:333)
This makes some sense to me since if I try to execute an insert on sql command line with the id field specified I get an error too.
INSERT INTO STUDENT_BATCH (id, BOARD_NAME, CONTACT_INFO, CREATE_TS, FILENAME, NOTES, SCHOOLBOARD)
VALUES (null, 'abc', 'def', current_timestamp, 'aaa', 'aabb', '1234');
gives me this:
Error code -1, SQL state 42Z23: Attempt to modify an identity column 'ID'.
Line 1, column 1
Execution finished after 0 s, 1 error(s) occurred.
however, this insert statement is successful:
INSERT INTO STUDENT_BATCH (BOARD_NAME, CONTACT_INFO, CREATE_TS, FILENAME, NOTES, SCHOOLBOARD)
VALUES ('abc', 'def', current_timestamp, 'aaa', 'aabb', '1234');
returns
Executed successfully in 0.002 s, 1 rows affected.
Line 1, column 1
Execution finished after 0.002 s, 0 error(s) occurred.
Seems to me that Eclipselink should know about how Derby handles identity columns and should not pass the id column at all on the insert statement. Is there a workaround for this or I should I just dump Derby and use some other database?
EclipseLink does not include the Id in the INSERT for Derby IDENTITY, so you have something odd going on.
Did you previously use another generator strategy and not recompile/deploy your code correctly?
Also try setting your platform using the"eclipselink.target-database"="Derby" in your persistence.xml.