Datatype for time period - postgresql

Question

I would like to insert time period into table column. For example: I've got a table with 7 columns, each column is a day of a week. Is there a possibility to create a datatype that is a time period for employees work hours? Let's say from 1AM to 8AM. Or in 24h system.
If there is not, how should i deal with it?

Answer 1

If you're building a table of something like business hours, you're probably better off with fewer columns.
create table business_hours (
day_of_week char(3) not null unique
check (day_of_week in ('Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun')),
start_time time not null,
end_time time not null
check (end_time > start_time)
);
insert into business_hours values
('Mon', '09:00', '17:00'),
('Tue', '09:00', '17:00'),
('Wed', '09:00', '17:00'),
('Thu', '09:00', '17:00'),
('Fri', '09:00', '17:00'),
('Sat', '11:00', '15:00');
You can join that table with a calendar table (or create a calendar table on the fly with generate_series()) to produce the business hours for the current week.
select c.cal_date, bh.*
from calendar c
inner join business_hours bh on bh.day_of_week = c.day_of_week
where cal_date between '2013-01-20' and '2013-01-27'
order by cal_date
Arranging that data into a matrix is a presentation-level issue. Use application code to do that.
The simplest calendar table you can use for this kind of query has just two columns. (Mine uses English. Adjust abbreviations as you like, but they must match the abbreviations in the table "business_hours".)
CREATE TABLE calendar
(
cal_date date NOT NULL,
day_of_week character(3) NOT NULL,
CONSTRAINT cal_pkey PRIMARY KEY (cal_date),
CONSTRAINT cal_dow_values CHECK (day_of_week =
CASE
WHEN date_part('dow', cal_date) = 0 THEN 'Sun'
WHEN date_part('dow', cal_date) = 1 THEN 'Mon'
WHEN date_part('dow', cal_date) = 2 THEN 'Tue'
WHEN date_part('dow', cal_date) = 3 THEN 'Wed'
WHEN date_part('dow', cal_date) = 4 THEN 'Thu'
WHEN date_part('dow', cal_date) = 5 THEN 'Fri'
WHEN date_part('dow', cal_date) = 6 THEN 'Sat'
ELSE NULL
END)
);
CREATE INDEX ON calendar (day_of_week);
There are a lot of different ways to populate a calendar table--spreadsheet, PostgreSQL function, scripting language to generate a CSV file, etc.