如何管理 MySQL 数据库表中用户的可用性

Question

I am trying to make a database design and I have a tutor which can set his availability in two ways :

1. General availability in a week. Which basically tells that usually I'm free to teach on these days of week between these hours of those days. Eg I'm available on Monday from 4PM to 8PM, on Tuesday on 10AM to 1PM, etc.
2. Specific availability. Which tells that on this date I won't be available on general availability time but instead on these hours. Eg I'm available on Monday 28 June from 2PM to 5PM. If specific availability for a date is present then general availability won't be shown.

How do I design tables in order to save this availability information ?

Answer 1

For example provided your DB supports Time type, pseudocode

GeneralAvailability (
    TutorId int not null,
    DayOfWeek int not null, /* 1 .. 7*/
    TimeFrom Time not null,
    TimeTo Time  not null
) 

SpecialAvailability (
    TutorId  int not null,
    AvailDate Date not null, 
    TimeFrom Time not null,
    TimeTo Time  not null
) 

or generalized one

Availability (
    TutorId int  not null,
    DayOfWeek int, /* 1 .. 7, null */ 
    AvailDate Date, 
    TimeFrom Time  not null,
    TimeTo Time  not null,
    CHECK ((DayOfWeek IS NULL OR AvailDate IS NULL) AND (DayOfWeek IS NOT NULL OR AvailDate IS NOT NULL))
)