Database table design for scheduling tasks

Question

I want to be able to create schedules that can be executed based on a fixed date, repeated daily, repeated on a particular day of the week, repeated on a particular month of

Answer 1

I have read through the answers above and I think a lot of things are unnecessary, correct me if I'm wrong.

Here is what I think should be done:

Schedule

---

• Id

• type (Daily, monthly, weekly, fixed, yearly) - Enum

• frequency (Can be 1-7[days of week], 1-30(or 28)[days of month], 1-365[days of year] or null(for daily, fixed) - ArrayField(of ints) - [1, 7] OR [23] OR [235]OR null

• time (time of day in UTC) - ArrayField(of Char strings - ['9:00', '13:30']

• date (for fixed type) - datetime - 2009-03-21

• is_active (boolean) - for enabling, disabling the schedule

• name (CharField) - If you want to name the schedule

Rest of the fields would require context to what you are building.

Now, for this I'm thinking of running a cronjob every 30mins(I'm taking time input separated by 30mins) which runs a script(django management command in my case) which filters schedules from this table that need to be run:

Query would be something like this:

current_day_of_week = 3
current_day_of_month = 24
current_day_of_year = 114
current_time = 13:30
current_date = 2019-04-24

Filter records that match the below query(not even psuedo code)(I'm using Q objects(https://docs.djangoproject.com/en/2.2/topics/db/queries/#complex-lookups-with-q-objects)

Q(daily AND current_time) OR
Q(weekly AND current_day_of_week AND current_time) OR
Q(monthly AND current_day_of_month AND current_time) OR
Q(yearly AND current_day_of_year AND current_time) OR
Q(fixed AND current_date AND current_time)

Answer 2

Microsoft SQL Server has an efficient and flexible design: https://msdn.microsoft.com/en-us/library/ms178644.aspx

Answer 3

You could start with a simple table with the following generic schema for storing schedules (PostgreSQL). Consider every instance of a schedule run termed as a "job".

CREATE TABLE Schedule (
    id SERIAL UNIQUE,                      -- unique identifier for the job
    name varchar(64) NOT NULL,             -- human readable name for the job
    description text,                      -- details about the job
    schedule varchar(64) NOT NULL,         -- valid CRON expression for the job schedule
    handler varchar(64) NOT NULL,          -- string representing handler for the job
    args text NOT NULL,                    -- arguments for the job handler
    enabled boolean NOT NULL DEFAULT TRUE, -- whether the job should be run
    created_at timestamp NOT NULL,         -- when was the job created
    updated_at timestamp NOT NULL,         -- when was the job updated
    start_date timestamp,                  -- job should not run until this time
    end_date timestamp,                    -- job should not run after this time
    last_triggered_at timestamp,           -- when was the job last triggered
    meta json                              -- additional metadata for the job 
);

Answer 4

I think the accepted answer is much more complicated than it needs to be. This can be done with a single table like this:

Schedules

 - Id :int
 - Greetingid :int
 - Startdate :date
 - Frequencytype :char(1)
 - Frequencyinterval :int
 - Timeofday :time

Frequencytype would be one of the following values

• 'O' = Once
• 'D' = Daily
• 'W' = Weekly
• 'M' = Monthly
• 'A' = Annually

Frequencyinterval would be numeric and the meaning of the value depends on the value of frequencytype

• If type = 'Once' then value = 0 (no interval) schedule would execute on startdate
• If type = 'Daily' then value = # of days interval
• If type = 'Weekly' then 1 through 7 for day of the week
• If type = 'Monthly' then 1 through 31 for day of the month
• If type = 'Annually' then 1 through 365 for day of the year

Answer 5

This is the table structure i came up with;

Schedule
 - ScheduleName
 - ScheduleTypeId (Daily, Weekly, Monthly, Yearly, Specific)
 - StartDate
 - IntervalInDays
 - Frequency
 - FrequencyCounter

ScheduleDaily
 - ScheduleDailyId 
 - ScheduleId
 - TimeOfDay
 - StartDate
 - EndDate

ScheduleMonthly
 - ScheduleMonthlyId
 - ScheduleId
 - DayOfMonth
 - StartDate
 - EndDate

ScheduleSpecific
 - ScheduleSpecificId
 - ScheduleId
 - SpecificDate
 - StartDate

...

ScheduleJob
 - ScheduleJobId
 - ScheduleId
 - ScheduleTypeId
 - RunDate
 - ScheduleStatusId