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[CDO] Fetch multiple objects by CDOID [message #431300]

Tue, 07 July 2009 21:00

Kai Schlamp

Messages: 344
Registered: July 2009

Senior Member

Hello.

For perfomance reasons I need to do some direct SQL queries (regexp search in the database). As
there is no query implemented for CDO yet, I thought of just connecting to the database directly
(beside the CDO connection) and query for the CDOID's directly.
What would be the best way to load the objects then with CDO?
Just use Transaction.getObject(cdoId, true)? Even if it is a very large list of CDOID's (about 50000)?

Regards,
Kai

Report message to a moderator

Re: [CDO] Fetch multiple objects by CDOID [message #431307 is a reply to message #431300]

Wed, 08 July 2009 06:24

Eike Stepper

Messages: 6510
Registered: July 2009

Senior Member

This is a multi-part message in MIME format.
--------------000100060707050409000706
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

Kai,

I strongly recommend to spend your time on efforts that are more
re-usable ;-)
Yesterday Martin implemented HQL for the HibernateStore within only 2 or
3 hours:

|/**
* Implements server side HQL query execution..
*
* @author Martin Taal
*/
*public class *HibernateQueryHandler *implements *IQueryHandler
{
*public static final *String QUERY_LANGUAGE = "hql";

*public static final *String FIRST_RESULT = "firstResult";

*private *HibernateStoreAccessor hibernateStoreAccessor;

/**
* Executes hql queries. Gets the session from the {@link HibernateStoreAccessor} creates a hibernate query and sets
* the parameters taken from the {@link CDOQueryInfo#getParameters()}. Takes into account the
* {@link CDOQueryInfo#getMaxResults()} and the {@link HibernateQueryHandler#FIRST_RESULT} values for paging.
*
* @param info
* the object containing the query and parameters
* @param context
* the query results are placed in the context
* @see IQueryHandler#executeQuery(CDOQueryInfo, IQueryContext)
*/
*public **void *executeQuery(CDOQueryInfo info, IQueryContext context)
{
*if *(!QUERY_LANGUAGE.equals(info.getQueryLanguage().toLowerCase ()))
{
*throw new *IllegalArgumentException("Query language " + info.getQueryLanguage() + " not supported by this store");
}

// get a transaction, the hibernateStoreAccessor is placed in a threadlocal
// so all db access uses the same session.
*final *Session session = hibernateStoreAccessor.getHibernateSession();
*try*
{
// create the query
*final *Query query = session.createQuery(info.getQueryString());

// get the parameters with some parameter conversion
*int *firstResult = -1;
*for *(String key : info.getParameters().keySet())
{
*if *(key.toLowerCase().equals(FIRST_RESULT.toLowerCase()))
{
*final *Object o = info.getParameters().get(key);
*if *(o != *null*)
{
*try*
{
firstResult = (Integer)o;
}
*catch *(ClassCastException e)
{
*throw new *IllegalArgumentException("Parameter firstResult must be an integer but it is a " + o
+ " class " + o.getClass().getName());
}
}
}
*else*
{
// in case the parameter is a CDOID get the object from the db
*final *Object param = info.getParameters().get(key);
*if *(param *instanceof *CDOIDHibernate)
{
*final *CDOIDHibernate hibernateId = (CDOIDHibernate)param;
query.setEntity(key, session.get(hibernateId.getEntityName(), hibernateId.getId()));
}
*else*
{
query.setParameter(key, param);
}
}
}

// set the first result
*if *(firstResult > -1)
{
query.setFirstResult(firstResult);
}

// the max result
*if *(info.getMaxResults() != CDOQueryInfo.UNLIMITED_RESULTS)
{
query.setMaxResults(info.getMaxResults());
}

// and go for the query
// future extension: support iterate, scroll through a parameter
*for *(Object o : query.list())
{
*final **boolean *addOneMore = context.addResult(o);
*if *(!addOneMore)
{
*return*;
}
}
}
*finally*
{
hibernateStoreAccessor.endHibernateSession();
}
}

*public *HibernateStoreAccessor getHibernateStoreAccessor()
{
*return *hibernateStoreAccessor;
}

*public **void *setHibernateStoreAccessor(HibernateStoreAccessor hibernateStoreAccessor)
{
*this*.hibernateStoreAccessor = hibernateStoreAccessor;
}
}|

Cheers
/Eike

----
http://thegordian.blogspot.com
http://twitter.com/eikestepper

Kai Schlamp schrieb:
> Hello.
>
> For perfomance reasons I need to do some direct SQL queries (regexp
> search in the database). As there is no query implemented for CDO yet,
> I thought of just connecting to the database directly (beside the CDO
> connection) and query for the CDOID's directly.
> What would be the best way to load the objects then with CDO?
> Just use Transaction.getObject(cdoId, true)? Even if it is a very
> large list of CDOID's (about 50000)?
>
> Regards,
> Kai

--------------000100060707050409000706
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
Kai, 
 
I strongly recommend to spend your time on efforts that are more
re-usable ;-) 
Yesterday Martin implemented HQL for the HibernateStore within only 2
or 3 hours: 
 
<title></title>
<style type="text/css">

</style>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">



<div class="java" align="left">
<table bgcolor="#ffffff" border="0" cellpadding="3" cellspacing="0">
<tbody>
<tr>
 <td align="left" nowrap="nowrap"
valign="top"> <code>/** 
  * Implements server side&nbsp ;HQL query execution.. 
 *  
 * @author Martin Taal 
 */ 
public class HibernateQueryHandler implements IQueryHandler 
{ 
  public static final  String QUERY_LANGUAGE =  "hql"; 
 
  public static final  String FIRST_RESULT =  "firstResult"; 
 
  private HibernateStoreAccessor hibernateStoreAccessor; 
 
  /** 
    * Executes hql queries.  Gets the session from th e  {@link HibernateStoreAccessor}  creates a hibernate query&nbs p;and sets 
    * the parameters taken f rom the  {@link CDOQueryInfo#getParameters()} . Takes into account the 
   * {@link CDOQueryInfo#getMaxResults()}  and the  {@link HibernateQueryHandler#FIRST_RESULT}&nbsp ; values for paging. 
   *  
   * @param info 
    *     &nbsp ;    the object  containing the query an d parameters 
   * @param context 
    *     &nbsp ;    the query& amp;nbsp;results are placed in&am p;nbsp;the context 
   * @see  IQueryHandler#executeQuery(CDOQueryInfo, IQueryCont ext) 
   */ 
  public void executeQuery( CDOQueryInfo info, IQueryContext  context ) 
  { 
    if (!QUERY_LANGUAGE.equals(info.getQueryLanguage().toLowerCase())) 
    { 
        throw new IllegalArgumentException("Query language "  + info.getQueryLanguage() + "  not supported by this&a mp;nbsp;store "); 
    } 
 
     // get a transaction, th e hibernateStoreAccessor is place d in a threadlocal 
     // so all db access& nbsp;uses the same session. 
    final  Session session = hibernateStoreA ccessor.getHibernateSession (); 
    try 
    { 
        // create the query 
        final  Query query = session.createQuery (info.getQueryString()); 
 
        // get the parameters wi th some parameter conversion 
        int firstResult = -1; 
        for (String key : info.getParameters ().keySet()) 
        { 
           if (key.toLowerCase().equals(FIRST_RESULT.toLowerCase())) 
           { 
             final Object o = info.getParameters ().get(key); 
             if (o != null) 
             { 
               try 
               { 
                  firstResult = (Integer)o; 
               } 
               catch (ClassCastException e) 
               { 
                  throw new IllegalArgumentException(" Parameter firstResult must be& ;nbsp;an integer but it  is a  " + o 
                      + " class " + o.getClass().getName()); 
               } 
             } 
           } 
           else 
           { 
             // in case the parameter  is a CDOID get&nbsp ;the object from the db 
             final  Object param = info.getParameters ().get(key); 
             if (param instanceof CDOIDHibernate) 
             { 
               final CDOIDHibernate hibernateId =  (CDOIDHibernate)param; 
               query.setEntity(key, session.get(hibernateId.getEntityName(), hibernateId.getId())); 
             } 
             else 
             { 
               query.setParameter(key, param); 
             } 
           } 
        } 
 
        // set the first result 
        if (firstResult > -1) 
        { 
           query.setFirstResult(firstResult); 
        } 
 
        // the max result 
        if (info.getMaxResults() != CDOQueryInfo.UNLIMITED_RESULTS ) 
        { 
           query.setMaxResults(info.getMaxResults()); 
        } 
 
        // and go for the&nb sp;query 
        // future extension: support& nbsp;iterate, scroll through a&am p;nbsp;parameter 
        for (Object o : query.list ()) 
        { 
           final boolean addOneMore = context.addResult (o); 
           if (!addOneMore) 
           { 
             return; 
           } 
        } 
    } 
    finally 
    { 
        hibernateStoreAccessor.endHibernateSession (); 
    } 
  } 
 
  public HibernateStoreAccessor getHibernateStoreAccessor () 
  { 
    return hibernateStoreAccessor; 
  } 
 
  public void setHibernateStoreAccessor(HibernateStoreAccessor hibernateStoreAccessor ) 
  { 
    this .hibernateStoreAccessor = hibernateStoreAc cessor; 
  } 
}</code> </td>
 </tr>
</tbody>
</table>
</div>

 
Cheers 
/Eike 
 
---- 
<a class="moz-txt-link-freetext" href="http://thegordian.blogspot.com">http://thegordian.blogspot.com</a> 
<a class="moz-txt-link-freetext" href="http://twitter.com/eikestepper">http://twitter.com/eikestepper</a> 
 
 
 
Kai Schlamp schrieb:
<blockquote cite="mid:h30d1n$uau$1@build.eclipse.org" type="cite">Hello.
 
 
For perfomance reasons I need to do some direct SQL queries (regexp
search in the database). As there is no query implemented for CDO yet,
I thought of just connecting to the database directly (beside the CDO
connection) and query for the CDOID's directly.
 
What would be the best way to load the objects then with CDO?
 
Just use Transaction.getObject(cdoId, true)? Even if it is a very large
list of CDOID's (about 50000)?
 
 
Regards,
 
Kai
 
</blockquote>
</body>
</html>

--------------000100060707050409000706--

Cheers
/Eike

----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper

Report message to a moderator

Re: [CDO] Fetch multiple objects by CDOID [message #431309 is a reply to message #431307]

Wed, 08 July 2009 07:35

Kai Schlamp

Messages: 344
Registered: July 2009

Senior Member

Ok, sounds reasonable. I'll see what I can do.

Eike Stepper wrote:
> Kai,
>
> I strongly recommend to spend your time on efforts that are more
> re-usable ;-)
> Yesterday Martin implemented HQL for the HibernateStore within only 2 or
> 3 hours:
>
> |/**
> * Implements server side HQL query execution..
> *
> * @author Martin Taal
> */
> *public class *HibernateQueryHandler *implements *IQueryHandler
> {
> *public static final *String QUERY_LANGUAGE = "hql";
>
> *public static final *String FIRST_RESULT = "firstResult";
>
> *private *HibernateStoreAccessor hibernateStoreAccessor;
>
> /**
> * Executes hql queries. Gets the session from the {@link HibernateStoreAccessor} creates a hibernate query and sets
> * the parameters taken from the {@link CDOQueryInfo#getParameters()}. Takes into account the
> * {@link CDOQueryInfo#getMaxResults()} and the {@link HibernateQueryHandler#FIRST_RESULT} values for paging.
> *
> * @param info
> * the object containing the query and parameters
> * @param context
> * the query results are placed in the context
> * @see IQueryHandler#executeQuery(CDOQueryInfo, IQueryContext)
> */
> *public **void *executeQuery(CDOQueryInfo info, IQueryContext context)
> {
> *if *(!QUERY_LANGUAGE.equals(info.getQueryLanguage().toLowerCase ()))
> {
> *throw new *IllegalArgumentException("Query language " + info.getQueryLanguage() + " not supported by this store");
> }
>
> // get a transaction, the hibernateStoreAccessor is placed in a threadlocal
> // so all db access uses the same session.
> *final *Session session = hibernateStoreAccessor.getHibernateSession();
> *try*
> {
> // create the query
> *final *Query query = session.createQuery(info.getQueryString());
>
> // get the parameters with some parameter conversion
> *int *firstResult = -1;
> *for *(String key : info.getParameters().keySet())
> {
> *if *(key.toLowerCase().equals(FIRST_RESULT.toLowerCase()))
> {
> *final *Object o = info.getParameters().get(key);
> *if *(o != *null*)
> {
> *try*
> {
> firstResult = (Integer)o;
> }
> *catch *(ClassCastException e)
> {
> *throw new *IllegalArgumentException("Parameter firstResult must be an integer but it is a " + o
> + " class " + o.getClass().getName());
> }
> }
> }
> *else*
> {
> // in case the parameter is a CDOID get the object from the db
> *final *Object param = info.getParameters().get(key);
> *if *(param *instanceof *CDOIDHibernate)
> {
> *final *CDOIDHibernate hibernateId = (CDOIDHibernate)param;
> query.setEntity(key, session.get(hibernateId.getEntityName(), hibernateId.getId()));
> }
> *else*
> {
> query.setParameter(key, param);
> }
> }
> }
>
> // set the first result
> *if *(firstResult > -1)
> {
> query.setFirstResult(firstResult);
> }
>
> // the max result
> *if *(info.getMaxResults() != CDOQueryInfo.UNLIMITED_RESULTS)
> {
> query.setMaxResults(info.getMaxResults());
> }
>
> // and go for the query
> // future extension: support iterate, scroll through a parameter
> *for *(Object o : query.list())
> {
> *final **boolean *addOneMore = context.addResult(o);
> *if *(!addOneMore)
> {
> *return*;
> }
> }
> }
> *finally*
> {
> hibernateStoreAccessor.endHibernateSession();
> }
> }
>
> *public *HibernateStoreAccessor getHibernateStoreAccessor()
> {
> *return *hibernateStoreAccessor;
> }
>
> *public **void *setHibernateStoreAccessor(HibernateStoreAccessor hibernateStoreAccessor)
> {
> *this*.hibernateStoreAccessor = hibernateStoreAccessor;
> }
> }|
>
>
> Cheers
> /Eike
>
> ----
> http://thegordian.blogspot.com
> http://twitter.com/eikestepper
>
>
>
> Kai Schlamp schrieb:
>> Hello.
>>
>> For perfomance reasons I need to do some direct SQL queries (regexp
>> search in the database). As there is no query implemented for CDO yet,
>> I thought of just connecting to the database directly (beside the CDO
>> connection) and query for the CDOID's directly.
>> What would be the best way to load the objects then with CDO?
>> Just use Transaction.getObject(cdoId, true)? Even if it is a very
>> large list of CDOID's (about 50000)?
>>
>> Regards,
>> Kai

Report message to a moderator

Re: [CDO] Fetch multiple objects by CDOID [message #431310 is a reply to message #431309]

Wed, 08 July 2009 07:36

Eike Stepper

Messages: 6510
Registered: July 2009

Senior Member

Kai,

Note that there is:

248933: [DB] Support SQL as a CDOQuery language
https://bugs.eclipse.org/bugs/show_bug.cgi?id=248933

Cheers
/Eike

----
http://thegordian.blogspot.com
http://twitter.com/eikestepper

Kai Schlamp schrieb:
> Ok, sounds reasonable. I'll see what I can do.
>
> Eike Stepper wrote:
>> Kai,
>>
>> I strongly recommend to spend your time on efforts that are more
>> re-usable ;-)
>> Yesterday Martin implemented HQL for the HibernateStore within only 2
>> or 3 hours:
>>
>> |/**
>> * Implements server side HQL query execution..
>> * * @author Martin Taal
>> */
>> *public class *HibernateQueryHandler *implements *IQueryHandler
>> {
>> *public static final *String QUERY_LANGUAGE = "hql";
>>
>> *public static final *String FIRST_RESULT = "firstResult";
>>
>> *private *HibernateStoreAccessor hibernateStoreAccessor;
>>
>> /**
>> * Executes hql queries. Gets the session from the {@link
>> HibernateStoreAccessor} creates a hibernate query and sets
>> * the parameters taken from the {@link
>> CDOQueryInfo#getParameters()}. Takes into account the
>> * {@link CDOQueryInfo#getMaxResults()} and the {@link
>> HibernateQueryHandler#FIRST_RESULT} values for paging.
>> * * @param info
>> * the object containing the query and parameters
>> * @param context
>> * the query results are placed in the context
>> * @see IQueryHandler#executeQuery(CDOQueryInfo, IQueryContext)
>> */
>> *public **void *executeQuery(CDOQueryInfo info, IQueryContext context)
>> {
>> *if *(!QUERY_LANGUAGE.equals(info.getQueryLanguage().toLowerCase ()))
>> {
>> *throw new *IllegalArgumentException("Query language " +
>> info.getQueryLanguage() + " not supported by this store");
>> }
>>
>> // get a transaction, the hibernateStoreAccessor is placed in a
>> threadlocal
>> // so all db access uses the same session.
>> *final *Session session =
>> hibernateStoreAccessor.getHibernateSession();
>> *try*
>> {
>> // create the query
>> *final *Query query = session.createQuery(info.getQueryString());
>>
>> // get the parameters with some parameter conversion
>> *int *firstResult = -1;
>> *for *(String key : info.getParameters().keySet())
>> {
>> *if *(key.toLowerCase().equals(FIRST_RESULT.toLowerCase()))
>> {
>> *final *Object o = info.getParameters().get(key);
>> *if *(o != *null*)
>> {
>> *try*
>> {
>> firstResult = (Integer)o;
>> }
>> *catch *(ClassCastException e)
>> {
>> *throw new *IllegalArgumentException("Parameter
>> firstResult must be an integer but it is a " + o
>> + " class " + o.getClass().getName());
>> }
>> }
>> }
>> *else*
>> {
>> // in case the parameter is a CDOID get the object from the db
>> *final *Object param = info.getParameters().get(key);
>> *if *(param *instanceof *CDOIDHibernate)
>> {
>> *final *CDOIDHibernate hibernateId = (CDOIDHibernate)param;
>> query.setEntity(key,
>> session.get(hibernateId.getEntityName(), hibernateId.getId()));
>> }
>> *else*
>> {
>> query.setParameter(key, param);
>> }
>> }
>> }
>>
>> // set the first result
>> *if *(firstResult > -1)
>> {
>> query.setFirstResult(firstResult);
>> }
>>
>> // the max result
>> *if *(info.getMaxResults() != CDOQueryInfo.UNLIMITED_RESULTS)
>> {
>> query.setMaxResults(info.getMaxResults());
>> }
>>
>> // and go for the query
>> // future extension: support iterate, scroll through a parameter
>> *for *(Object o : query.list())
>> {
>> *final **boolean *addOneMore = context.addResult(o);
>> *if *(!addOneMore)
>> {
>> *return*;
>> }
>> }
>> }
>> *finally*
>> {
>> hibernateStoreAccessor.endHibernateSession();
>> }
>> }
>>
>> *public *HibernateStoreAccessor getHibernateStoreAccessor()
>> {
>> *return *hibernateStoreAccessor;
>> }
>>
>> *public **void *setHibernateStoreAccessor(HibernateStoreAccessor
>> hibernateStoreAccessor)
>> {
>> *this*.hibernateStoreAccessor = hibernateStoreAccessor;
>> }
>> }|
>>
>>
>> Cheers
>> /Eike
>>
>> ----
>> http://thegordian.blogspot.com
>> http://twitter.com/eikestepper
>>
>>
>>
>> Kai Schlamp schrieb:
>>> Hello.
>>>
>>> For perfomance reasons I need to do some direct SQL queries (regexp
>>> search in the database). As there is no query implemented for CDO
>>> yet, I thought of just connecting to the database directly (beside
>>> the CDO connection) and query for the CDOID's directly.
>>> What would be the best way to load the objects then with CDO?
>>> Just use Transaction.getObject(cdoId, true)? Even if it is a very
>>> large list of CDOID's (about 50000)?
>>>
>>> Regards,
>>> Kai

Cheers
/Eike

----
http://www.esc-net.de
http://thegordian.blogspot.com
http://twitter.com/eikestepper

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