I'm a designer, so pretty newb when it comes to development logic, so these will be really simple questions as I try to learn a bit :)

I want a dataobject that will be included on every page. It will contain contact info that will be slightly different on certain pages. I want each page to only have 1 dataobject though many might exist.

Here is my setup:

class ContactInfo extends DataObject {
    static $db = array(
        'Title' => 'Varchar',
        'Info' => 'HTMLText'

    );

    static $belongs_many_many = array(
        'Pages' => 'Page'
    );

}

public static $many_many = array(
		'Info' => 'ContactInfo'
	);


	public function getCMSFields() {
        $fields = parent::getCMSFields();

        $contactInfo = new GridField(
            'ContactInfo',
            'Contact Information',
            $this->Info(),
            GridFieldConfig_RelationEditor::create()
        );

        $fields->addFieldToTab('Root.ContactInfo', $contactInfo);
        return $fields;
    }

Is this the proper way to set this up? I'm finding when I delete a dataobject on the page, it removes it completely and not just from this page. I was under the impression the GridFieldConfig_RelationEditor::create() would allow only the deletion from the page.

How do I limit it so each page only can include 1? The thing is, I'll have say 3 dataobjects that I want to use across all my pages, so some will be on more than 1 page. I don't want it unique to that page.

to fix RelationEditor() from deleting the object do this. I believe this is a bug in 3.0.2 and will hopefully be corrected in the next release.

$gridFieldConfig = GridFieldConfig_RelationEditor::create();
$gridFieldConfig->removeComponentsByType('GridFieldDeleteAction');
$gridFieldConfig->addComponent(new GridFieldDeleteAction(true));
$contactInfo = new GridField( 
'ContactInfo', 
'Contact Information', 
$this->Info(), 
$gridFieldConfig     

I can't help on limiting it to only one though. I'm interested in learning that myself. If i do figure out a solution i'll be sure to post it here.

Oh okay thanks! I thought maybe my relationship was setup incorrect so I was pretty puzzled for a while. A bug makes sense.

And that would be great if you find anything about limiting it to 1. It isn't urgent for what I'm setting up now, but I think it would be a good feature to know moving forward.