IMap(TKey, TValue).AddIndex Method

IMapTKey, TValueAddIndex Method

Hazelcast .Net Client Class Library

Adds an index to this map for the specified entries so that queries can run faster.

Namespace: Hazelcast.Core
Assembly: Hazelcast.Net (in Hazelcast.Net.dll) Version: 3.7.1

Syntax

void AddIndex(
	string attribute,
	bool ordered
)

Sub AddIndex ( 
	attribute As String,
	ordered As Boolean
)

void AddIndex(
	String^ attribute, 
	bool ordered
)

abstract AddIndex : 
        attribute : string * 
        ordered : bool -> unit

Parameters

attribute: Type: SystemString
attribute of value
ordered: Type: SystemBoolean
true if index should be ordered, false otherwise.

Remarks

Adds an index to this map for the specified entries so that queries can run faster.

Let's say your map values are Employee objects.

Copy

public class Employee :IPortable
{
    private bool active = false;
    private int age;
    private string name = null;
    // other fields.

}

If you are querying your values mostly based on age and active then you should consider indexing these fields.

Copy

var imap = Hazelcast.GetMap("employees");
imap.AddIndex("age", true);        // ordered, since we have ranged queries for this field
imap.AddIndex("active", false);    // not ordered, because boolean field cannot have range

Index attribute should either have a getter method or be public. You should also make sure to add the indexes before adding entries to this map.

Reference

IMapTKey, TValue Interface

Hazelcast.Core Namespace