CHECK or DEFAULT constraint VS increment a DATE value by N days (INT)

Question

1.00/5 (1 vote)

See more:

Hello,

I would like to set a CHECK or DEFAULT constraint to ensure that a Date2 is always equal to Date1 + 5 days.

My problem is that I can't do operations with a DATE value and an INT value

What I have tried:

ALTER TABLE TableName
ADD CONSTRAINT DF_Date2_ExpiringDate DEFAULT Date1 +30 FOR Date2;

ALTER TABLE TableName
ADD CONSTRAINT CK_TableName_Date2Is30DaysAfterDate1
        CHECK (Date2= Date1+ 30);

Posted 4-Nov-20 3:34am

xhon

Updated 4-Nov-20 3:41am

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Richard Deeming · Accepted Answer · 2020-11-04T03:42:00

If Date2 is always five days after Date1, then you don't need to store Date2 at all. Just use a computed column.

SQL

ALTER TABLE TableName
DROP COLUMN Date2;

ALTER TABLE TableName
ADD Date2 As (DateAdd(day, 5, Date1));

Specify Computed Columns in a Table - SQL Server | Microsoft Docs[^]

As per your previous question[^], if you ever need Date2 to be anything other than Date1 + 5 days, you cannot add a CHECK constraint to your table.