code: function findPrim(columns,field) {
  
      var primary_keys = columns.filter(function (r) {return r.Key === 'PRI';});
  
      //for multiple primary keys, just take the first
      if(primary_keys.length > 0) {
          return primary_keys[0].Field;
      }
  
      //If the provided field is a string, we might have a chance
      if(typeof field === "string") {
          if(checkIfFieldsExist(field,columns)) {
              return escape(field);
          }
      }
  
      //FALLBACK
      return "id";
  }
docs: Get primary key, or if specified
  @param columns
  @param field
  @returns {*}