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Result Transformers

Our criteria builder also supports the notion of projections (http://docs.jboss.org/hibernate/core/3.3/reference/en/html/querycriteria.html#querycriteria-projection). A projection is used to change the nature of the results, much how a result transformer does. However, there are several projection types you can use which are great for doing counts, distinct counts, max values, sums, averages and much more. This is great when you do paging as obviously you do not want to execute two queries: one for the pagination and another for the total reuslts count. Below are the available projections you can use:

You will use them by passing them to the withProjections() method as arguments that match the projection type. The value of the argument is one, a list or an array of property names to run the projection on, with the exception of id and rowcount which take a boolean true. Also, you can pass in a string separated with a : to denote an alias on the property when doing the SQL. The alias can then be used with any restriction the criteria builder can use.

Ex: avg="balance", avg="balance:myBalance", avg="balance, total", avg=["balance","total"]

INFO If the :alias is not used, then the alias becomes the property name.

// Using native approach for one projection only
var results = c.like("firstName","Lui%")
     .and( 
          c.restrictions.between( "balance", 200, 300),
          c.restrictions.eq("department", "development")
     )
     .setProjection( c.projections.rowCount() )
     .get();

// Using the withProjections() method, which enables you to do more than 1 projection
var results = c.like("firstName","Lui%")
     .and( 
          c.restrictions.between( "balance", 200, 300),
          c.restrictions.eq("department", "development")
     )
     .withProjections(rowCount=1)
     .get();

var results = c.like("firstName","Lui%")
     .and( 
          c.restrictions.between( "balance", 200, 5000),
          c.restrictions.eq("department", "development")
     )
     .withProjections(avg="balance,total",max="total:maxTotal")
     .gt("maxTotal",500)
     .list();

Result Transformers

Ex: avg="balance", avg="balance:myBalance", avg="balance, total", avg=["balance","total"]

INFO If the :alias is not used, then the alias becomes the property name.

// Using native approach for one projection only
var results = c.like("firstName","Lui%")
     .and( 
          c.restrictions.between( "balance", 200, 300),
          c.restrictions.eq("department", "development")
     )
     .setProjection( c.projections.rowCount() )
     .get();

// Using the withProjections() method, which enables you to do more than 1 projection
var results = c.like("firstName","Lui%")
     .and( 
          c.restrictions.between( "balance", 200, 300),
          c.restrictions.eq("department", "development")
     )
     .withProjections(rowCount=1)
     .get();

var results = c.like("firstName","Lui%")
     .and( 
          c.restrictions.between( "balance", 200, 5000),
          c.restrictions.eq("department", "development")
     )
     .withProjections(avg="balance,total",max="total:maxTotal")
     .gt("maxTotal",500)
     .list();