Restrict specific date format Data into Table - sql

Question

I Have a table called Sur_Data and the data looks like:
ID SV_Date
258 13/01/2010
569 15/02/2011
695 26/05/2010
745 12/06/2010
Now I want to select the ID's from that table and insert into another table so we are using something like:
Insert into Surdate(ID)
Select ID from Sur_Data
where ISDATE(SV_Date) = 1
Since the format in SV_Date is different it is not inserting any records into Surdate table.
So I am trying to see is there a way that we could restrict the data in Sur_Data table to have only date's that are in MM/DD/YYYY format.So whenever they try to insert records of different format it should throw an error.
Can anyone help on this?

Answer 1

Edit: for example 2 & 3, ANSI WARNINGS must be off.
IS_DATE function is influenced by DATEFORMAT setting for current SQL Server session/connection.
Example 1:
DECLARE #d1 VARCHAR(25) = '26/05/2010'
,#d2 VARCHAR(25) = '15/02/2011';
PRINT '*****Test 1*****'
SET DATEFORMAT DMY;
SELECT ISDATE(#d1), ISDATE(#d2);
PRINT '*****Test 2*****'
SET DATEFORMAT MDY;
SELECT ISDATE(#d1), ISDATE(#d2);
Results:
*****Test 1*****
----------- -----------
1 1
(1 row(s) affected)
*****Test 2*****
----------- -----------
0 0
(1 row(s) affected)
Now, you can see how DATEFORMAT influences ISDATE function.
Instead of ISDATE function you can use CONVERT function with different date/time styles. If a [n][var]char value doesn't have the selected style then CONVERT function will return NULL. For dd/mm/yyyy values (british) can be used style 103 and for mm/dd/yyyy values (U.S.) can be used style 101.
Example 2:
SET ANSI_WARNINGS OFF;
SET ARITHABORT OFF;
DECLARE #Results TABLE
(
ID INT PRIMARY KEY
,SV_Date VARCHAR(20) NOT NULL
);
INSERT #Results
VALUES
(258, '13/01/2010')
,(569, '15/02/2011')
,(695, '26/05/2010')
,(745, '12/06/2010');
SELECT *
,ISDATE(r.SV_Date) [IS_DATETIME]
,CONVERT(DATETIME,r.SV_Date,103) [IS_DATETIME British/French style=dd/mm/yyyy]
,CONVERT(DATETIME,r.SV_Date,101) [IS_DATETIME U.S. style=mm/dd/yyyy]
,CASE
WHEN CONVERT(DATETIME,r.SV_Date,103) IS NOT NULL AND CONVERT(DATETIME,r.SV_Date,101) IS NULL THEN 'IS_DMY'
WHEN CONVERT(DATETIME,r.SV_Date,103) IS NULL AND CONVERT(DATETIME,r.SV_Date,101) IS NOT NULL THEN 'IS_MDY'
WHEN CONVERT(DATETIME,r.SV_Date,103) IS NOT NULL AND CONVERT(DATETIME,r.SV_Date,101) IS NOT NULL THEN 'IS_DMY_OR_MDY'
WHEN CONVERT(DATETIME,r.SV_Date,103) IS NULL AND CONVERT(DATETIME,r.SV_Date,101) IS NULL THEN 'IS_NOT_DMY_OR_MDY'
END
FROM #Results r;
Results:
ID SV_Date IS_DATETIME IS_DATETIME British/French style=dd/mm/yyyy IS_DATETIME U.S. style=mm/dd/yyyy
----------- -------------------- ----------- ------------------------------------------- --------------------------------- -----------------
258 13/01/2010 0 2010-01-13 00:00:00.000 NULL IS_DMY
569 15/02/2011 0 2011-02-15 00:00:00.000 NULL IS_DMY
695 26/05/2010 0 2010-05-26 00:00:00.000 NULL IS_DMY
745 12/06/2010 1 2010-06-12 00:00:00.000 2010-12-06 00:00:00.000 IS_DMY_OR_MDY
Now, if you want to check SV_Date values for mm/dd/yyyy format (style 101 - U.S.) then you can use a CHECK constraint like this:
Example 3:
DECLARE #Results2 TABLE
(
ID INT PRIMARY KEY
,SV_Date VARCHAR(20) NOT NULL
,CHECK( CONVERT(DATETIME,SV_Date,101) IS NOT NULL )
);
SET ANSI_WARNINGS OFF;
INSERT #Results2
VALUES (258, '13/01/2010');
INSERT #Results2
VALUES (569, '15/02/2011');
INSERT #Results2
VALUES (695, '26/05/2010');
INSERT #Results2
VALUES (745, '12/06/2010');
SELECT *
FROM #Results2;
Results:
ID SV_Date
----------- --------------------
745 12/06/2010
(1 row(s) affected)
Observations:
If you want to find current DATEFORMAT setting (current session) then you can use sys.dm_exec_sessions view:
SELECT s.date_format, s.date_first
FROM sys.dm_exec_sessions s
WHERE s.session_id = ##SPID

Answer 2

To strictly answer the question, you could create a function (CLR or TSQL) and apply that as a column constraint/check.
But as #joe Stefanelli correctly points out, store it as a datetime data type and let the client handle the presentation format.
Edit
http://msdn.microsoft.com/en-us/library/ms190273.aspx
ALTER TABLE
dbo.Sur_Data
WITH CHECK
ADD CONSTRAINT ck_dateFormatted CHECK (dbo.VerifyDateFormat(SV_Date) = 1) ;
Which assumes you've defined a function that returns 1 if the format matches the expectation.