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Hi, i used ZK with OpenJPA to save data into Java DB. But got error when inserting a row with not setting auto-increment field value. this might not a ZK problem, but I just want anyone here can help me sort out this problem.
I create the database table by:
DROP TABLE USERS; Create TABLE USERS( ID INT generated by default as identity PRIMARY KEY, NAME VARCHAR(20) NOT NULL, LOGINID VARCHAR(20) NOT NULL, PASSWORD VARCHAR(32) NOT NULL, AGE INT NOT NULL ); INSERT INTO USERS values(default,'Mr Zhang','Zhang3','zzz333',18); INSERT INTO USERS values(default,'Mr Lee','Li4','Lii4',28);
I created the entity bean by Netbeans as:
@Entity
@Table(name = "USERS")
@NamedQueries({@NamedQuery(name = "Users.findAll", query = "SELECT u FROM Users u"), @NamedQuery(name = "Users.findById", query = "SELECT u FROM Users u WHERE u.id = :id"), @NamedQuery(name = "Users.findByName", query = "SELECT u FROM Users u WHERE u.name = :name"), @NamedQuery(name = "Users.findByLoginid", query = "SELECT u FROM Users u WHERE u.loginid = :loginid"), @NamedQuery(name = "Users.findByPassword", query = "SELECT u FROM Users u WHERE u.password = :password"), @NamedQuery(name = "Users.findByAge", query = "SELECT u FROM Users u WHERE u.age = :age")})
public class Users implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "ID")
private Integer id;
...
In ZK page, i got componment's value by:
void AddIt()
{
//get values from zk textbox componments
Users newUser = new Users ();
newUser.setName(tbName.value);
newUser.setLoginid(tbLoginid.value);
newUser.setPassword(tbPassword.value);
newUser.setAge(Integer.parseInt(tbAge.value));
//call to Insert() in controller.java
ContDAO.Insert(newUser);
}
In the controller bean:
//DAO operations
public void Insert(Users urs) {
final EntityManager em = emf.createEntityManager();
try {
em.getTransaction().begin();
em.persist(urs);
em.getTransaction().commit();
} finally {
em.close();
}
}
When run the project, it display error message as:
The field "id" of instance "entity.Users[id=null]" contained a null value; the metadata for this field specifies that nulls are illegal.
Please help for this problem. Thanks a lot.
@kingsz1,
Try this.
DROP TABLE USERS; Create TABLE USERS( ID INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY CONSTRAINT users_pk PRIMARY KEY, NAME VARCHAR(20) NOT NULL, LOGINID VARCHAR(20) NOT NULL, PASSWORD VARCHAR(32) NOT NULL, AGE INT NOT NULL ); INSERT INTO USERS (ID, NAME, LOGINID, PASSWORD, AGE) values(default,'Mr Zhang','Zhang3','zzz333',18); INSERT INTO USERS (ID, NAME, LOGINID, PASSWORD, AGE) values(default,'Mr Lee','Li4','Lii4',28);
not tested:
------------
in your usersDAOImpl you can do by creating a new USERS object following
that it's not null either pre-initialize.
@Override
public Users create() {
Users users = new Users();
users.setId(Integer.MIN_VALUE);
return users;
}
Stephan
Thank you. this way:
users.setId(Integer.MIN_VALUE);
then get error message:
The generated value processing detected an existing value assigned to this field: entity.Users.id. This existing value was either provided via an initializer or by calling the setter method. You either need to remove the @GeneratedValue annotation or modify the code to remove the initializer processing.
Hmmm, sorry more i cannot do. Hope others find a solution.
Cause this problems i'm working not with autoIncrement Fields.
I work with a sequence or PKField table.
Stephan
PS: Have you an initializer ???
Thank you again. this way is ok:
Create table:
DROP TABLE USERS; DROP TABLE OPENJPA_SEQUENCE_TABLE; CREATE TABLE OPENJPA_SEQUENCE_TABLE (ID SMALLINT NOT NULL, SEQUENCE_VALUE BIGINT, PRIMARY KEY (ID)); Create TABLE USERS( ID INT generated by default as identity CONSTRAINT USERS_pk PRIMARY KEY, NAME VARCHAR(20) NOT NULL, LOGINID VARCHAR(20) NOT NULL, PASSWORD VARCHAR(32) NOT NULL, AGE INT NOT NULL );
The entity bean, change little:
// @GeneratedValue(strategy = GenerationType.IDENTITY)
@GeneratedValue(strategy = GenerationType.AUTO)
DO NOT insert row before running project, otherwise error
>>org.apache.openjpa.persistence.RollbackException: The transaction has been rolled back. See the nested exceptions for details on the errors that occurred.
>>org.apache.openjpa.persistence.EntityExistsException: The transaction has been rolled back. See the nested exceptions for details on the errors that occurred.
>>org.apache.openjpa.persistence.EntityExistsException: 语句异常终止，因为它导致“USERS”上所定义的“USERS_PK”标识的唯一或主键约束或唯一索引中出现重复键值。 {prepstmnt 28122412 INSERT INTO USERS (ID, AGE, LOGINID, NAME, PASSWORD) VALUES (?, ?, ?, ?, ?) [params=(int) 1, (int) 12, (String) bbb, (String) aaaa, (String) cc]} [code=-1, state=23505]
[SQL: -1, 23505]
From the message, we know the openjpa handling primary key from 1. Therefore if we insert any row before running the project, it causes the ID field has same value 1 in rows.
I am wondering how to set the openjpa to handle primary key by adding 1 to the last ID value.
Hmmm, i think Select max(ID) +1 from users
Stephan
Asked: 2009-03-31 14:34:44 +0800
Seen: 1,878 times
Last updated: Apr 01 '09