/**
* Add a foreign column for the relation
*
* @param Column $column
*
* @return $this
* @throws Exception\Manager
*/
public function addForeignColumn(Column $column)
{
$alias = $this->normalizeName($column->getName());
if ($this->foreignColumns->offsetExists($alias) === true) {
throw Exception\Relation::foreignColumnAlreadyExists($alias, $this->getName());
}
$this->foreignColumns->offsetSet($alias, $column);
return $this;
}
