How to Specify Specific Columns in Hibernate Criteria Queries?

Specifying Specific Columns in Hibernate Criteria Queries

In Hibernate, the default Criteria Query retrieves all columns from the target table. However, it is often desirable to exclude certain columns for performance or security reasons. Here's how to accomplish this:

Using Projections

Projections allow you to specify the specific columns you wish to retrieve. This can be achieved by using the Projections.projectionList() method and adding the desired properties:

<code class="java">Criteria cr = session.createCriteria(User.class)
    .setProjection(Projections.projectionList()
      .add(Projections.property("id"), "id")
      .add(Projections.property("Name"), "Name"));</code>

Handling Alias Conflict

When using projections, it's necessary to handle alias conflicts since Hibernate generates aliases for the returned columns. To resolve this, you can use the setResultTransformer() method with Transformers.aliasToBean() to transform the results into an expected object:

<code class="java">cr.setResultTransformer(Transformers.aliasToBean(User.class));</code>

Query Example

Consider the updated query in your post to retrieve specific columns:

<code class="sql">select
    this_.TEMPLATE_ID,
    this_.TEMPLATE_NAME,
    this_.CREATE_DATE,
    this_.UPDATE_DATE,
    this_.STATUS_CODE,
    this_.USER_ID
from
    templates this_ 
where
    this_.STATUS_CODE = 1
    and this_.PRACTICE_ID = 1 
    and this_.USER_ID in (1, 2) 
order by
    this_.TEMPLATE_NAME asc
limit ?</code>

To translate this into a Hibernate Criteria Query, you can use the following code:

<code class="java">Criteria cr = session.createCriteria(Template.class)
    .setProjection(Projections.projectionList()
      .add(Projections.property("TEMPLATE_ID"), "TEMPLATE_ID")
      .add(Projections.property("TEMPLATE_NAME"), "TEMPLATE_NAME")
      .add(Projections.property("CREATE_DATE"), "CREATE_DATE")
      .add(Projections.property("UPDATE_DATE"), "UPDATE_DATE")
      .add(Projections.property("STATUS_CODE"), "STATUS_CODE")
      .add(Projections.property("USER_ID"), "USER_ID"))
    .add(Restrictions.eq("this_.STATUS_CODE", 1))
    .add(Restrictions.eq("this_.PRACTICE_ID", 1))
    .add(Restrictions.in("this_.USER_ID", Arrays.asList(1, 2)))
    .addOrder(Order.asc("this_.TEMPLATE_NAME"))
    .setResultTransformer(Transformers.aliasToBean(Template.class));</code>

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