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 |