How to find by date from timestamp column in JPA c

Question

I want to find a record by date. In entity and database table, datatype is timestamp. I used Oracle database.

@Entity
public class Request implements Serializable {
  @Id
  private String id;
  @Version
  private long version;
  @Temporal(TemporalType.TIMESTAMP)
  @Column(name = "CREATION_DATE")
  private Date creationDate;

  public Request() {
  }

  public Request(String id, Date creationDate) {
    setId(id);
    setCreationDate(creationDate);
  }

  public String getId() {
    return id;
  }

  public void setId(String id) {
    this.id = id;
  }

  public long getVersion() {
    return version;
  }

  public void setVersion(long version) {
    this.version = version;
  }

  public Date getCreationDate() {
    return creationDate;
  }

  public void setCreationDate(Date creationDate) {
    this.creationDate = creationDate;
  }
}

in mian method

public static void main(String[] args) {
    RequestTestCase requestTestCase = new RequestTestCase();
    EntityManager em = Persistence.createEntityManagerFactory("Criteria").createEntityManager();

    em.getTransaction().begin();
    em.persist(new Request("005",new Date()));
    em.getTransaction().commit();

    Query q = em.createQuery("SELECT r FROM Request r WHERE r.creationDate = :creationDate",Request.class);
    q.setParameter("creationDate",new GregorianCalendar(2012,12,5).getTime());
    Request r = (Request)q.getSingleResult();
    System.out.println(r.getCreationDate());        

}

In Oracle database record is,

ID      CREATION_DATE                   VERSION

006     05-DEC-12 05.34.39.200000 PM    1

Exception is,

Exception in thread "main" javax.persistence.NoResultException: getSingleResult() did     not retrieve any entities.
at    org.eclipse.persistence.internal.jpa.EJBQueryImpl.throwNoResultException(EJBQueryImpl.java:1246)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.getSingleResult(EJBQueryImpl.java:750)
at com.ktrsn.RequestTestCase.main(RequestTestCase.java:29)

Answer 1

You can use the native query in the jpql.

Example(SQL server):

select table from table where convert(date,mydate)=:date_colum

Answer 2

The SIMPLEST WAY to compare date of two datetimes

compare two date and ignore time

WHERE DATE(dbdDate) = DATE(yourDate)

Answer 3

The DB type is TIMESTAMP and not DATE, meaning you store exact times.

When using new GregorianCalendar(2012,12,5).getTime() you are quering timestamps that match the given date at 00:00:00.000 and that doesn't exist in your DB

You should either change the DB to store dates instead of timestamps or change your query.

JPA 2 got YEAR, MONTH and DAY functions so you can

SELECT WHERE YEAR(yourdate) = YEAR(dbdate) AND MONTH(yourdate) = MONTH(dbdate) and DAY(yourdate) = DATE(dbdate)

In Criteria API you can do something like this:

Expression<Integer> yourdateYear = cb.function("year", Integer.class, yourdate);
Expression<Integer> yourdateMonth = cb.function("month", Integer.class, yourdate);
Expression<Integer> yourdateDay = cb.function("day", Integer.class, yourdate);

Then combine them with the AND expression and do the same for the date field in db and compare them.