entity-framework sql sql-server

Should I use a primary key id if table means nothing alone?

I have a table called ‘Date Restriction’ and it basically holds the following properties:

DayId    : int
DateFrom : datetime
DateTo : datetime
EventId : int // this is a foreign key

Now the way I would access this is to get the event I want and then look at the associated Date Restrictions.

Is it good practise or recommended to add a primary key column to this table if I never have to reference the date restriction alone?