Socialengine DB fix

I have two installations of Social Engine. Need to share user tables across .I created views for user tables in second installation that selects data from user tables in first installation. Getting error: exception 'Zend_Db_Table_Exception' with message 'A table must have a primary key, but none was found for table 'engine4_user' This approach of views works well in Joomla,Oxwall etc but since Social Engine uses Zend , it seems that something is causing error. Need expert to fix this.