Okay, I found the solution, there is a way to have fields associated to entities without bundles. You use the same name for bundle as entity. Fortunately, I was also able to use entity reference field. Sharing my experience with everyone -- <a href="http://www.innoraft.com/blog/use-entity-reference-your-custom-entities-without-bundles">http://www.innoraft.com/blog/use-entity-reference-your-custom-entities-without-bundles</a><div>
<br><div class="gmail_quote">On Wed, Dec 7, 2011 at 6:56 PM, Mukesh Agarwal <span dir="ltr"><<a href="mailto:mukesh.agarwal17@gmail.com">mukesh.agarwal17@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
Hi Guys,<div><br></div><div>Entities seem to be the biggest problem of my life for the past few weeks :-)</div><div><br></div><div>Ok, so I have an entity without any bundles. I read this in <a href="http://api.drupal.org/api/drupal/modules--system--system.api.php/function/hook_entity_info/7" target="_blank">hook_entity_info</a> that bundles are not necessary. </div>
<div><br></div><blockquote class="gmail_quote" style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<span style="color:rgb(34,34,34);font-family:'Lucida Grande','DejaVu Sans','Bitstream Vera Sans',Verdana,Arial,sans-serif;font-size:13px;line-height:18px;background-color:rgb(255,255,255)">This entry can be omitted if this entity type exposes a single bundle (all entities have the same collection of fields). The name of this single bundle will be the same as the entity type.</span></blockquote>
<div><br></div><div>Now, I need to attach fields to my entity. I use <a href="http://api.drupal.org/api/drupal/modules--field--field.crud.inc/function/field_create_field/7" target="_blank">field_create_field</a> for my entity reference field which seems to work fine. When I attach this field to my instance using <a href="http://api.drupal.org/api/drupal/modules--field--field.crud.inc/function/field_create_instance/7" target="_blank">field_create_instance</a>, I see an error saying:</div>
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drupal FieldException: Attempt to create an instance of field without a bundle</blockquote><div><br></div><div>Does this mean I cannot attach fields to entities which do not have bundles? </div><span class="HOEnZb"><font color="#888888"><div>
<br></div>-- <br>Cheers,<div>
Mukesh Agarwal</div><div>________________________________</div><div><font color="#999999"><a href="http://www.innoraft.com" target="_blank">Innoraft Solutions</a> || </font><span style="color:rgb(153,153,153)">+91 8017220799</span></div>
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</blockquote></div><br><br clear="all"><div><br></div>-- <br>Cheers,<div>Mukesh Agarwal</div><div>________________________________</div><div><font color="#999999"><a href="http://www.innoraft.com" target="_blank">Innoraft Solutions</a> || </font><span style="color:rgb(153, 153, 153)">+91 8017220799</span></div>
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