That is a binary operator in hibernate you should use 

    is not null

Have a look at [14.10. Expressions][1]


  [1]: http://docs.jboss.org/hibernate/core/3.3/reference/en/html/queryhql.html

No. You have to use `is null` and `is not null` in HQL.

If you do want to use `null` values with `&#39;=&#39;` or `&#39;&lt;&gt;&#39;` operators you may find the 

&gt; [answer from @egallardo hier][1]

very useful.

Short example for `&#39;=&#39;`: The expression

    WHERE t.field = :param

you refactor like this

    WHERE ((:param is null and t.field is null) or t.field = :param)

Now you can set the parameter `param` either to some non-null value or to `null`:

    query.setParameter(&quot;param&quot;, &quot;Hello World&quot;); // Works
    query.setParameter(&quot;param&quot;, null);          // Works also

  [1]: https://stackoverflow.com/a/21593066/1860309

No. See also this link [Handle conditional null in HQL][1] for tips and tricks on how to handle comparisons with both null and non-null values.


  [1]: https://stackoverflow.com/a/21593066/761918

I have a Visual Studio 2010 solution with a few projects. I can successfully build with Build -&gt; Build Solution or Build -&gt; Build MyCompany.MyProduct.MyProject. After building I press CTRL+F5 and successfully run the start up project. This works as expected.

After I change a source file, save it and then again build (with either Build -&gt; Build Solution or Build -&gt; Build MyCompany.MyProduct.MyProject) it builds successfully. I am still able to press CTRL+F5 and run the startup project. This again works as expected.

The problem is in the following scenario:
After I change a source file, save it and directly press CTRL+F5 then Visual Studio 2010 says BUILD FAILED and there are no errors. And it doesn&#39;t start my startup project (of course).

Am I missing something?

Visual Studio 2010 says Build failed with no errors after I change a source file

I am loading a listview from Http server, 20 at a time ,**At the end of Listview I a want to load next 20 data from server** and this process will continue till data ends in server ,I used class that extend BaseAdapter to populate first 20 data .what should i do??


Android Dynamically load Listview at scroll end?

Does *hibernate* convert `column != null` in *HQL* to a `column is null` in *SQL*?

HQL &quot;is null&quot; And &quot;!= null&quot; on an Oracle column

Does hibernate convert <code>column != null</code> in HQL to a <code>column is null</code> in SQL?

Is there any way to modify an existing check constraint on a table 
**other than dropping and re-creating it**?

    create table t ( n number);
    ora10g&gt; Tabelle wurde erstellt.
    
    ora10g&gt; alter table t add constraint ck check(n&gt;0);
    
    Tabelle wurde ge&#245;ndert.
    
    ora10g&gt; alter table t modify constraint ck check(n&lt;0);
    alter table t modify constraint ck check(n&lt;0)
                                       *
    FEHLER in Zeile 1:
    ORA-00933: SQL-Befehl wurde nicht korrekt beendet




how to modify an existing check constraint?

How can I use a package variable in a simple SELECT query statement in Oracle?

Something like

    SELECT * FROM MyTable WHERE TypeId = MyPackage.MY_TYPE

Is it possible at all or only when using PL/SQL (use SELECT within BEGIN/END)?

How to use a package constant in SQL SELECT statement?

Oracle constraint name is known.

How do I find the name of the table for which this constraint is applied?

Get table name by constraint name

The default behaviour of `LIKE` and the other comparison operators, `=` etc is case-sensitive.

Is it possible make them case-insensitive?

Case insensitive searching in Oracle

 - What is it a BLOB?
 - How can I use it?
 - What are the differences between DBMS&#39;s BLOBs. I would like to save data using BLOBs into any DBMS and then read that BLOB with a library.



What is it exactly a BLOB in a DBMS context

Let&#39;s say I have a table with millions of rows. Using JPA, what&#39;s the proper way to iterate over a query against that table, such that **I don&#39;t have all an in-memory List** with millions of objects?

For example, I suspect that the following will blow up if the table is large:

    List&lt;Model&gt; models = entityManager().createQuery(&quot;from Model m&quot;, Model.class).getResultList();

    for (Model model : models)
    {
         System.out.println(model.getId());
    }

Is pagination (looping and manually updating `setFirstResult()`/`setMaxResult()`) really the best solution?

**Edit**: the primary use-case I&#39;m targeting is a kind of batch job. It&#39;s fine if it takes a long time to run. There is no web client involved; I just need to &quot;do something&quot; for each row, one (or some small N) at a time. I&#39;m just trying to avoid having them all in memory at the same time.





JPA: what is the proper pattern for iterating over large result sets?

I&#39;ve been doing some work with Hibernate 3.5 and Spring 3 recently, I&#39;m fairly new with Hibernate and thought the `HibernateDaoSupport` class in Spring made it nice and easy to use Hibernate with my domain classes.

However, while searching for an unrelated question I saw someone mention that the `HibernateDaoSupport` is not the best way to use Spring and Hibernate. Can anyone shed any light on:

 - Why is it not recommended?
 - What is the best (or at least the accepted) way to integrate Hibernate and Spring?


Why is HibernateDaoSupport not recommended?

My database contains 3 tables:
User and Service entities have many-to-many relationship and are joined with the SERVICE_USER table as follows:

USERS - SERVICE_USER - SERVICES

SERVICE_USER table contains additional BLOCKED column.

What is the best way to perform such a mapping?
These are my Entity classes

    @Entity
    @Table(name = &quot;USERS&quot;)
    public class User implements java.io.Serializable {
    
    private String userid;
    private String email;
    
    @Id
    @Column(name = &quot;USERID&quot;, unique = true, nullable = false,)
    public String getUserid() {
    return this.userid;
    }
    
    .... some get/set methods
    }
    
    @Entity
    @Table(name = &quot;SERVICES&quot;)
    public class CmsService implements java.io.Serializable {
    private String serviceCode;
    
    @Id
    @Column(name = &quot;SERVICE_CODE&quot;, unique = true, nullable = false, length = 100)
    public String getServiceCode() {
    return this.serviceCode;
    }
    .... some additional fields and get/set methods
    }

I followed this example http://giannigar.wordpress.com/2009/09/04/m ... using-jpa/
Here is some test code:

    User user = new User();
    user.setEmail(&quot;e2&quot;);
    user.setUserid(&quot;ui2&quot;);
    user.setPassword(&quot;p2&quot;);
    
    CmsService service= new CmsService(&quot;cd2&quot;,&quot;name2&quot;);
    
    List&lt;UserService&gt; userServiceList = new ArrayList&lt;UserService&gt;();
    
    UserService userService = new UserService();
    userService.setService(service);
    userService.setUser(user);
    userService.setBlocked(true);
    service.getUserServices().add(userService);
    
    userDAO.save(user);

The problem is that hibernate persists User object and UserService one. No success with the CmsService object

I tried to use EAGER fetch - no progress

Is it possible to achieve the behaviour I&#39;m expecting with the mapping provided above?

Maybe there is some more elegant way of mapping many to many join table with additional column?

Mapping many-to-many association table with extra column(s)

Is it using some kind of byte codes modification to the original classes?

Or, maybe Hibernate get the dirty state by compare the given object with previously persisted version?

I&#39;m having a problem with `hashCode()` and `equals()` methods for complicated objects. I feel it would be very slow to compute hash code if the object has collection members, and cyclic references are also a problem.

If Hibernate won&#39;t use `hashCode()`/`equals()` to check the dirty state, I guess I should not use `equals()`/`hashCode()` for the entity object (not value object), but I&#39;m also afraid if the same operator (`==`) is not enough.

So, the questions are:

1. How does Hibernate know if a property of an object is changed?

2. Do you suggest to override the `hashCode()`/`equals()` methods for complicated objects? What if they contains cyclic references?

    And, also, 

3. Would `hashCode()`/`equals()` with only the `id` field be enough?


How does Hibernate detect dirty state of an entity object?

What is the difference between Unidirectional and Bidirectional associations?

Since the table generated in the db are all the same,so the only difference I found is that each side of the bidiretional assocations will have a refer to the other,and the unidirectional not.


**This is a Unidirectional association**

    public class User {
    	private int		id;
    	private String	name;
    	@ManyToOne
    	@JoinColumn(
    			name = &quot;groupId&quot;)
    	private Group	group;
    }
    
    public class Group {
    	private int		id;
    	private String	name;
    }
    
**The Bidirectional association**
    
    public class User {
    	private int		id;
    	private String	name;
    	@ManyToOne
    	@JoinColumn(
    			name = &quot;groupId&quot;)
    	private Group	group;
    }
    public class Group {
    	private int			id;
    	private String		name;
    	@OneToMany(mappedBy=&quot;group&quot;)
    	private List&lt;User&gt;	users;
    }


The difference is whether the group holds a reference of the user.

So I wonder if this is the only difference? which is recommended?

What is the difference between Unidirectional and Bidirectional JPA and Hibernate associations?

I want to know what the difference is between `null` and `undefined` in JavaScript.

What is the difference between null and undefined in JavaScript?

1. How do I check a variable if it&#39;s `null` or `undefined` and what is the difference between the `null` and `undefined`?

2. What is the difference between `==` and `===` (it&#39;s hard to search Google for &quot;===&quot; )?


JavaScript checking for null vs. undefined and difference between == and ===

I&#39;m using an array variable in PowerShell 2.0.  If it does not have a value, it will be $null, which I can test for successfully:

    PS C:\&gt; [array]$foo = $null
    PS C:\&gt; $foo -eq $null
    True

But when I give it a value, the test for $null does not return anything:

    PS C:\&gt; [array]$foo = @(&quot;bar&quot;)
    PS C:\&gt; $foo -eq $null
    PS C:\&gt;

How can &quot;-eq $null&quot; give no results?  It&#39;s either $null or it&#39;s not.

What is the correct way to determine if an array is populated vs. $null?

How to test for $null array in PowerShell

I&#39;m writing C code for a system where address 0x0000 is valid and contains port I/O. Therefore, any possible bugs that access a NULL pointer will remain undetected and at the same time cause dangerous behaviour.

For this reason I wish to redefine NULL to be another address, to for example an address that isn&#39;t valid. If I accidentally access such an address I will get a hardware interrupt where I can handle the error. I happen to have access to stddef.h for this compiler, so I can actually alter the standard header and redefine NULL.

My question is: will this conflict with the C standard? As far as I can tell from 7.17 in the standard, the macro is implementation-defined. Is there anything elsewhere in the standard stating that NULL *must* be 0?

Another issue is that plenty of compilers perform static initialization by setting everything to zero, no matter the data type. Even though the standard says that the compiler should set integers to zero and pointers to NULL. If I would redefine NULL for my compiler, then I know that such static initialization will fail. Could I regard that as incorrect compiler behaviour even though I boldly altered compiler headers manually? Because I know for certain that this particular compiler does not access the NULL macro when doing static initialization.

Redefining NULL

I am using Doctrine 1.1 in Zend. I am trying to write a query that will return records that have a null value in a certain column.

		$q = Doctrine_Query::create()
		-&gt;select(&#39;a.*&#39;)
		-&gt;from(&#39;RuleSet a&#39;)
        -&gt;where(&#39;a.vertical_id = ?&#39;, null);

		$ruleset_names_result = $q-&gt;execute(array(), Doctrine::HYDRATE_ARRAY);

I have three records in the ruleset table which have a _NULL_ value in the vertical_id column yet the query doest not find these.

Appreciate the help.

Sid.

Content Type	Original Author	Original Content on Stackoverflow
Question	Eric V	View Question on Stackoverflow
Solution 1 - Oracle	Eduard	View Answer on Stackoverflow
Solution 2 - Oracle	JB Nizet	View Answer on Stackoverflow
Solution 3 - Oracle	Boris Brodski	View Answer on Stackoverflow
Solution 4 - Oracle	egallardo	View Answer on Stackoverflow

HQL "is null" And "!= null" on an Oracle column

Oracle Problem Overview

Oracle Solutions

Solution 1 - Oracle

Solution 2 - Oracle

Solution 3 - Oracle

Solution 4 - Oracle

Android Dynamically load Listview at scroll end?

Visual Studio 2010 says Build failed with no errors after I change a source file

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