Hi, I want to have relation between member and guest(visitor).

I understand that member has many guests and guest has one member, but in this situation it don't save GuestID, just MemberID which page I visited.
So when I want to know who visited, I don't get that GuestID.

How to set relation between member and guest properly? Thanks for any help..

Should I just have relation like this in Guest.php:

private static $has_many = array(
"Member" => "Member",
"Guest" => "Member"
);

Just want to know if I do it right way?

Your wording sounds very odd, in that guests don't normally have any objects associated with them, but I guess you're doing something I don't particularly understand.

To create a relation, you should define it on BOTH objects, just once for each.

visitor has_one member (defined in the visitor class)
member has_many guest (defined via a DataExtension applied to Member)

Relation help: http://iforce.co.nz/i/quv5meng.sv4.png
defining relations: http://doc.silverstripe.org/en/developer_guides/model/relations/
working with DataExtension: http://doc.silverstripe.org/en/developer_guides/model/extending_dataobjects/

I will try to explain.

Member.php code:

class MemberExtension extends DataExtension {
	...
	static $has_many = array(
              'Guests' => 'Guest'
	);
	...	
} 

And Guest.php

class Guest extends Dataobject {
	...
	static $has_one = array(
              'Member' => 'Member'
	);
	...	
} 

Let's say I visit other member profile and system automaticaly creates Guest record in database with that member ID. So that member has 1 guest.
But where to add my member ID as guest? Should I just have:

class Guest extends Dataobject {
	...
	static $has_one = array(
              'Member' => 'Member',
              'Guest' => 'Member'
	);
	...	
} 

And fill GuestID with my member ID?
Hope you understand :)

It sounds as if a Guest is a Member, and you're tracking who's viewing whom's page.

in which case Guest should also be a dataextension (probably in the same dataextension), and it also sounds as if the relationship should be many_many, as a guest can visit any number of members, not just one.

In which case it's more like:

private static $many_many = ['Guests'=>'Member'];
private static $belongs_many_many = ['Visited'=>'Member']

Am I right?

It is I who still does not understand you.
Here it would be best if you explained _what_ you're trying to achieve, not _how_ you're trying to achieve it.

Ok, let's say I have dating portal, I visit members profiles, they visit mine profile. So I want to track who visited my profile, return list of these members. Also, I want to get a list, which members I visited.
So I want to understand what relation should I use. Thanks for helpping :)

So, no help?