Store multiple bit values in a single table column

Question

I need to store some sort of day-of-week scheduling in database, where I can schedule a record (say it represents a task) for a day or multiple days of the week. I need to h

Answer 1

You are talking about a "bit mask". These are handy devices as you can apply binary math on them to easily check the values, but they do take a little setup. To expand on that a little more it would look something like this.

-- You will want to work with constants
DECLARE @Mon INT, @Tue INT, @Wed INT, @Thu INT, @Fri INT, @Sat INT, @Sun INT

SET @Mon = POWER(2,0) -- 1
SET @Tue = POWER(2,1) -- 2
SET @Wed = POWER(2,2) -- 4
SET @Thu = POWER(2,3) -- 8
SET @Fri = POWER(2,4) -- 16
SET @Sat = POWER(2,5) -- 32
SET @Sun = POWER(2,6) -- 64

-- Set Monday and Wednesday
UPDATE T SET Schedule = @Mon | @Wed

-- Find all tasks scheduled on Tuesday
SELECT * FROM T WHERE Schedule & @Tue = @Tue

-- Find all tasks scheduled on Tuesday and Saturday
SELECT * FROM T WHERE Schedule & @Tue | @Sat = @Tue | @Sat