code: public function addPrimaryKey($name, $table, $columns)
      {
          $time = $this->beginCommand("add primary key $name on $table (" . (is_array($columns) ? implode(',', $columns) : $columns) . ')');
          $this->db->createCommand()->addPrimaryKey($name, $table, $columns)->execute();
          $this->endCommand($time);
      }
docs: Builds and executes a SQL statement for creating a primary key.
  The method will properly quote the table and column names.
  @param string $name the name of the primary key constraint.
  @param string $table the table that the primary key constraint will be added to.
  @param string|array $columns comma separated string or array of columns that the primary key will consist of.