Francesco Francesco - 7 months ago 34
Java Question

Hibernate - TypedQuery.getResultList() returns a list of the same object

Here is a more and maybe better description of the problem:

I do a simple select query. The returning list contains the exact number of records/objects as if I do the same query in the DB, but the problem is that all the objects are the same/identical.

For ex, this is the result in the DB (I removed the null values):

26801 01-JAN-00 7 31-DEC-99 7 Obere Kirchstr. 26 CH 8304 Walliselln

26801 01-JAN-00 2 31-DEC-99 2 Obere Kirchstr. 26 CH 8304 Walliselln

And this is the content of the variable addresses as I can see it in Eclipse during the debugging after the query has been executed:

addresses ArrayList (id=81)

elementData Object[10] (id=86)

[0] DLDBAddress (id=82)

[1] DLDBAddress (id=82)

[2] null

...

modCount 1

size 2

DLDBAddress [persid=26801, valPeriodStart=1900-01-01, valPeriodEnd=9999-12-31, addressNr=7, addressType=7, addressRow1=null, addressRow2=Obere Kirchstr. 26, addressRow3=null, country=CH , postalCode=8304, city=Walliselln, phoneNr=null, faxNr=null, sekretaryPhoneNr=null, alternatPhoneNr=null, pagerNr=null]

DLDBAddress [persid=26801, valPeriodStart=1900-01-01, valPeriodEnd=9999-12-31, addressNr=7, addressType=7, addressRow1=null, addressRow2=Obere Kirchstr. 26, addressRow3=null, country=CH , postalCode=8304, city=Walliselln, phoneNr=null, faxNr=null, sekretaryPhoneNr=null, alternatPhoneNr=null, pagerNr=null]]

As you can see, the two objects are identical. They shoul instead differ from the addressNr and addressType...

This is the piece of code where I build up the query:

public static <T> List<T> findBy(EntityManager eM, Class<T> boClass, String whereClause, String whereValue)
{
EntityManager entityManager = eM;
Query query = entityManager.createQuery("from " + boClass.getName() + " s where s." + whereClause + " = " + whereValue);
...
return (List<T>) query.getResultList();
}


and this is the (quite simple) resulting query:

from ch.ethz.id.wai.pdb.bo.DLDBAddress s where s.persid = 26801

This is the generated query:

Hibernate:
select
dldbaddres0_.PERSID as PERSID0_,
dldbaddres0_.ADRNUM as ADRNUM0_,
dldbaddres0_.ADRZEIL1 as ADRZEIL3_0_,
dldbaddres0_.ADRZEIL2 as ADRZEIL4_0_,
dldbaddres0_.ADRZEIL3 as ADRZEIL5_0_,
dldbaddres0_.ADRTYP as ADRTYP0_,
dldbaddres0_.ADRAUSWTEL as ADRAUSWTEL0_,
dldbaddres0_.ADRORT as ADRORT0_,
dldbaddres0_.ADRLAND as ADRLAND0_,
dldbaddres0_.ADRFAX as ADRFAX0_,
dldbaddres0_.ADRPSA as ADRPSA0_,
dldbaddres0_.ADRTEL as ADRTEL0_,
dldbaddres0_.ADRPLZ as ADRPLZ0_,
dldbaddres0_.ADRSEKTEL as ADRSEKTEL0_,
dldbaddres0_.BISDAT as BISDAT0_,
dldbaddres0_.VONDAT as VONDAT0_
from
NETHZ.V_DLDB_ADRESSE dldbaddres0_
where
dldbaddres0_.PERSID=26801


And here the entity:

@Entity
@Table(name = "V_DLDB_ADRESSE", schema="NETHZ")
public class DLDBAddress
{
@Id
@Column(name = "PERSID", insertable = false, updatable = false)
private Integer persid;
@Temporal(TemporalType.DATE)
@Column(name = "VONDAT", insertable = false, updatable = false)
private Date valPeriodStart;
@Temporal(TemporalType.DATE)
@Column(name = "BISDAT", insertable = false, updatable = false)
private Date valPeriodEnd;
@Column(name = "ADRNUM", insertable = false, updatable = false)
private Integer addressNr;
@Column(name = "ADRTYP", insertable = false, updatable = false)
private Integer addressType;
@Column(name = "ADRZEIL1", insertable = false, updatable = false)
private String addressRow1;
@Column(name = "ADRZEIL2", insertable = false, updatable = false)
private String addressRow2;
@Column(name = "ADRZEIL3", insertable = false, updatable = false)
private String addressRow3;
@Column(name = "ADRLAND", insertable = false, updatable = false)
private String country;
@Column(name = "ADRPLZ", insertable = false, updatable = false)
private String postalCode;
@Column(name = "ADRORT", insertable = false, updatable = false)
private String city;
@Column(name = "ADRTEL", insertable = false, updatable = false)
private String phoneNr;
@Column(name = "ADRFAX", insertable = false, updatable = false)
private String faxNr;
@Column(name = "ADRSEKTEL", insertable = false, updatable = false)
private String secretaryPhoneNr;
@Column(name = "ADRAUSWTEL", insertable = false, updatable = false)
private String alternatPhoneNr;
@Column(name = "ADRPSA", insertable = false, updatable = false)
private String pagerNr;

...


Am I missing something?

Ah, I'm connecting to an Oracle DB.

Thanks in advance
Francesco

Answer
where dldbaddres0_.PERSID=26801

@Id
  @Column(name = "PERSID", insertable = false, updatable = false)

You defined PERSID as @Id, which is a primary key. Is it really unique for your application? From the behavior it is not. But for Hib it MUST be.

So what happens:

  1. You have two+ records in the database with PERSID = 26801
  2. You query them WHERE PERSID=26801
  3. SQL Query returns two+ rows
  4. Hib loads first one, and puts into session, with PERSID as a key (because it is marked as @Id). Object is placed into the result list.
  5. Hib loads second one, notices that an object with same @Id is already in the session, and just places the reference into the result List. Row data are ignored.
  6. Thus you get two+ copies.