Question

If I want to make sure an operation can only be done once a week by a user, what is an efficient way to do it? If a user has carried out that operation on Friday, then he can still do it on Tuesday, because it’s “next” week.

Answer 1

Create a table that stores a history of user actions:

CREATE TABLE UserActions (
   userId int,
   weekOfYear int,
   year int
)

To check if the user has performed an action during the same week, you can use the DATEPART function to determine the week:

IF EXISTS (SELECT * FROM UserActions WHERE userId = @userID and weekOfYear = DATEPART(isowk, GetDate() AND year = Year(GetDate())

If that returns NULL, the user hasn’t performed any actions in the current week. Then, you could insert a row after the action is performed.

INSERT INTO UserActions (userId, weekOfYear int, year) 
VALUES (@userId, DATEPART(isowk, GetDate(), Year(GetDate())