<xml> </xml>

db4o |

# com.db4o.query Namespace

Query package.

Namespace hierarchy

### Classes

Class | Description
--- | ---
Predicate | Base class for native queries.

### Interfaces

Interface | Description
--- | ---

Candidate

candidate for com.db4o.query.Evaluation callbacks.
During query execution all registered com.db4o.query.Evaluation callback handlers are called with com.db4o.query.Candidate proxies that represent the persistent objects that meet all other com.db4o.query.Query criteria.
A com.db4o.query.Candidate provides access to the persistent object it represents and allows to specify, whether it is to be included in the com.db4o.ObjectSet resultset.

Constraint

constraint to limit the objects returned upon query execution .
Constraints are constructed by calling Query.constrain() .
Constraints can be joined with the methods com.db4o.query.Constraint.And and com.db4o.query.Constraint.Or .
The methods to modify the constraint evaluation algorithm may be merged, to construct combined evaluation rules. Examples:

-     Constraint#smaller().equal()

  for "smaller or equal"

-     Constraint#not().like()

  for "not like"

-     Constraint#not().greater().equal()

  for "not greater or equal"

Constraints | set of com.db4o.query.Constraint objects. This extension of the com.db4o.query.Constraint interface allows setting the evaluation mode of all contained com.db4o.query.Constraint objects with single calls. See also com.db4o.query.Query.Constraints .
Evaluation | for implementation of callback evaluations.
Query | handle to a node in a S.O.D.A.
QueryComparator | Comparator for sorting queries on JDKs where java.util.Comparator is not available.

### Delegates

Delegate | Description
--- | ---
EvaluationDelegate |