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Work with a database View

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y0dA

Post subject: Work with a database View

Posted: Tue Jun 12, 2007 9:42 am

Newbie

Joined: Fri May 25, 2007 4:03 am
Posts: 15

Hi!
Someone know how I can work with hibernate and a view?
can I handle i view like i table?
what I have to set at the mapping file at primary key because the view hasnt someone?

code snippets:
mapping file:

Code:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
   "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
   "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="at.pcd.wam.technologie.persistence.model">
  <class name="at.pcd.wam.technologie.persistence.model.LocationPortalModel" table="V_STANDORT_PORTAL" >
    <!-- primary key -->
     <id name="id" type="string" column="E_30021_DBK">
     <generator class="increment"></generator>
     </id>     

   <property name="dbk" type="string" column="E_30019_DBK"></property>
   <property name="district" type="string" column="BEZIRK"></property>
   <property name="boroughNumber" type="integer" column="GEMEINDE_NR"></property>

  </class>
</hibernate-mapping>

--> table equals view name?
--> what I have to do with the primary key?

best regards

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pramodkp

Post subject:

Posted: Tue Jun 12, 2007 10:01 am

Regular

Joined: Mon Mar 26, 2007 12:38 am
Posts: 119

Hi,
>> can I handle i view like i table?
Yes.
Underlying database object ( table / view / synonym ) is transparent to Hibernate.

>>what I have to set at the mapping file at primary key because the view hasnt someone?
It is mandatory for all hibernate Entities to have an ID.
This is true in all cases. ( view / table / ... )
Further,
Any table ( or view ) should have at least one key to be in 1NF ( First Normal Form )
In extreme case, this could be a composite key with all columns.

------------------------------------------
Rate the reply if you find it helpful

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y0dA

Post subject:

Posted: Tue Jun 12, 2007 10:50 am

Newbie

Joined: Fri May 25, 2007 4:03 am
Posts: 15

thx, now i tried this but following exception occurred:

Code:

org.hibernate.exception.GenericJDBCException: could not execute query

Code:

java.sql.SQLException: Konvertierung zu interner Darstellung nicht erfolgreich

means -->

Code:

java.sql.SQLException: Fail to convert to internal representation

my view contains varchar columns and number columns:
varchar = string
number = double ?

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y0dA

Post subject:

Posted: Tue Jun 12, 2007 11:59 am

Newbie

Joined: Fri May 25, 2007 4:03 am
Posts: 15

query, in sb:

Code:

 SELECT * FROM V_STANDORT_PORTAL WHERE E_30019_DBK =  '301920000630141504440001' AND V_STANDORT_PORTAL.ANZAHL > 0

following get a response of "Ljava.lang.Object" but with them i cant work (casts didnt work):

Code:

values = (ArrayList<LocationPortalModel>) session.createSQLQuery(sb.toString()).list();   

if i run following it never comes to an end (no exception no end):

Code:

values = (ArrayList<LocationPortalModel>) session.createQuery(sb.toString()).list();

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rally25rs

Post subject:

Posted: Tue Jun 12, 2007 1:18 pm

Newbie

Joined: Tue Jun 12, 2007 12:36 pm
Posts: 6

I'm not sure about your casting problem, but for the .createQuery() method, it is expecting an HQL statement, not SQL.

The HQL equivalent would be:

Code:

from LocationPortalModel where dbk = '301920000630141504440001' and [i]anzahl[/i] > 0

I left "anzahl" in there as a place holder because it should be the property on your persistence object, but I don't see that column mapped to anything in the mapping you posted...[/i]

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y0dA

Post subject:

Posted: Wed Jun 13, 2007 1:50 am

Newbie

Joined: Fri May 25, 2007 4:03 am
Posts: 15

Well I also tried the following statement:

Code:

session.createQuery("from LocationPortalModel")list();

And this also didnt worked - hibernate will never come to an end - i always must break the calling.

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