How I Can create several items in database with the same ID

Hi all! I need your help please! I need to create next logic: a user can create service and then he can chooses days and times when this service is available. All of this I write to database. But I have a problem, because user can choose other dates and times for this service. For examle: service is available Mon, Wed ,Thu 1-5 PM. No problems for write this one. But when user picks one more days and times, for example Sut, Sun 5-8 PM I need add this days and times to database. And I guess I should separate this writes, because next I need to display times slots exactly for accurate day.
I can’t duplicate this service in database, because I need this services will be the same ID.
Maybe you will have any ideas how to write to database all of this.
Thank you

The best way is to have a different database to store the availability of your services. Basically 3 columns, start period (Date), end period (Date) and service (Service).