问题
I'm rather new to SQL Server, but I am working on an app where a record is added to a table, and is given a DateTime stamp.
I want to be able to dynamically update the Status column of this row, 1 hour after the row was added.
Is this possible without running some server side script or store procedure every couple minutes? Is there an efficient way to accomplish this?
回答1:
In Sql Server you can have Time Dependant or Action Dependent code execution.
Time Dependent
Time Dependant Code execution is handled via SQL Server Agent Jobs. You can execute a stored procedure or ad-hoc T-SQL code on a certain time of the day. It can be scheduled to execute on regular basis.
Action Dependent
Action Dependent Code execution is handled via Triggers (After/Instead of Triggers). A piece of code that is executed in response to a DML action INSERT, UPDATE or DELETE.
Solution
In your case you are trying to execute code in response to an action (Insert) after a certain period of time. I dont think there is an efficient way of doing it I would rather do the following....
You can have a Column called Created of Datetime datatype in your table and set a default value of GETDATE().
Now you dont need the status column. All you need is a query/View which will check at runtime if the row was added more than an hour ago and will return it STATUS as required.
Something like.....
CREATE VIEW dbo.vw_Current_Status
AS
SELECT *
, CASE WHEN DATEDIFF(MINUTE, Created, GETDATE()) >= 60
THEN 'OLD'
ELSE 'New' END AS [Status]
FROM TABLE_NAME
来源：https://stackoverflow.com/questions/25166271/dynamically-update-status-column-after-x-amount-of-time