IQuery Interface

Summary

Handle to a node in a S.O.D.A.
Assembly
Db4objects.Db4o-2010.dll
Namespace
Db4objects.Db4o.Query
Implementing Types
graph BT Type["IQuery"] class Type type-node Implementing0["QQuery"]-.->Type click Implementing0 "/db4o-gpl-doc/output/api/Db4objects.Db4o.Internal.Query.Processor/QQuery"

Syntax

public interface IQuery

Remarks

Handle to a node in a S.O.D.A. query graph. NOTE: Soda queries silently ignore invalid specified fields, constraints etc.

A node in the query graph can represent a class or an attribute of a class.

The graph is automatically extended with attributes of added constraints (see Db4objects.Db4o.Query.IQuery.Constrain(System.Object) ) and upon calls to Db4objects.Db4o.Query.IQuery.Descend(System.String) that request nodes that do not yet exist.

References to joined nodes in the query graph can be obtained by "walking" along the nodes of the graph with the method Db4objects.Db4o.Query.IQuery.Descend(System.String) .

Db4objects.Db4o.Query.IQuery.Execute evaluates the entire graph against all persistent objects.

Db4objects.Db4o.Query.IQuery.Execute can be called from any Db4objects.Db4o.Query.IQuery node of the graph. It will return an Db4objects.Db4o.IObjectSet filled with objects of the class/classes that the node, it was called from, represents.

Note:
Db4objects.Db4o.IObjectContainer.Query(Predicate) Native queries} are the recommended main query interface of db4o.

Methods

Name Value Summary
Constrain(Object) IConstraint
Adds a constraint to this node.
Constraints() IConstraints
Returns a Db4objects.Db4o.Query.IConstraints object that holds an array of all constraints on this node.
Descend(string) IQuery
Returns a reference to a descendant node in the query graph.
Execute() IObjectSet
Executes the Db4objects.Db4o.Query.IQuery .
OrderAscending() IQuery
Adds an ascending ordering criteria to this node of the query graph.
OrderDescending() IQuery
Adds a descending order criteria to this node of the query graph.
SortBy(IQueryComparator) IQuery
Sort the resulting ObjectSet by the given comparator.