trigger avoidPiDeletion on past_information__c (before delete) {
    
    list<id>conlist=new list<id>();
    
    for (past_information__c pi:trigger.old){
         system.debug('inside trigger ');
        conlist.add(pi.consultant__c);
   }
    
    map<id,consultant__c>conmap=new map<id,consultant__c>([select id from consultant__c where status__c='approved' and type__c='employee' and id in:conlist]);
    
    for(past_information__c pi:trigger.old){
        if(conmap.containsKey(pi.consultant__c)==true){
            pi.adderror('this record cannot be deleted as the consultant is an approved employee');
        }
        
    }
        
        
   
        
}