SQL Server 2005 vs. ASP.net datetime format confusion - asp.net

I've found a similar question on stack overflow, but it didn't really answer the question I have. I need to make sure that my asp.net application is formatting the date dd/mm/yyyy the same as my SQL Server 2005.
How do I verify the date culture (if that's what it's called) of the server matches how I've programmed my app? Are there specific database settings and OS settings? Is it table-specific? I don't want to transpose my days and months.
thank you

When you get a DateTime out of the database, it should be in a non-cultured format (like the DateTime object, based on the number of ticks since a certain date). It is only when you are converting that value into a string that you need to be concerned with culture. In those cases, you can use yourDateTimeValue.ToString("dd/MM/yyyy", CultureInfo.InvariantCulture) to make sure that the information displays correctly.

I belive that if you use SqlParameters ADO.NET will take care of the rest and you don't have to worry about it. Besides, it's good for defending against SQL Injection attacks too! :)

** Watch out because SQL DateTime columns are non-nullable and their minimum value is 1/1/1753 while .net DateTimes are non-nullable with min values of 1/1/0001. **
If you're pulling data from a real DateTime column, by default it will always be in the same standard format. For saving the data to the column, you might want to specify the SqlDbType.DateTime in your parameter.
i ripped this off of http://bytes.com/forum/thread767920.html :
com.Parameters.Add("#adate", SqlDbType.DateTime).Value = DateTime.Now;

Well, if you keep datetime fields in the DB you shouldn't worry about it.
As long as you keep the dates in app strongly typed (DateTime variables) and send the dates through prepared statements with DBParameter/SqlParameter your DB will take them as is.
If you use strings to hold your dates in code, some casts will ensure you send the right values:
string sqlCmd = #"SELECT *
FROM MyTable
WHERE MyDateField = CONVERT(datetime, '{0}', 101)";
// assuming myDateString is a string with a date in the local format
sqlCmd = string.Format(sqlCmd,
Convert.ToDateTime(myDateString).ToString("yyyyMMdd"));
(the code is ugly, but hopefully it gets the point across)

As others have mentioned, you should be OK as far as storing datetimes culturally. What I would recommend is that you store all of your times as standard UTC time. In SQL Server 2005 and older there is no way to store time zone information, but if everything is stored in universal time, you should be OK because the time can be converted to the local time later on.
SQL Server 2008 does have some datatypes that are aware of time zones, and if you're using .NET 3.5 there are tools to assist with time zone handling/conversions.
Definitely keep times in universal format. This will make a world of a difference if you have to work in multiple time zones.

Related

How do I modify the datetime format in Microsoft SQL Server?

I'm testing a query that I think is handling datetime values in a way that may not work for customers who aren't using a specific datetime format.
Here's the code:
WHERE order_instant >= CONCAT(YEAR(cast(getdate() as date)) ,'-01-01')
I suspect this code would break if a customer had datetimes formatted as anything other than year - month - day, but I'm having trouble testing that hunch.
The column datatype is datetime.
I'm looking for something analogous to the NLS settings in Oracle SQL Developer, which allows me to do things like display dates as YYYY-MON-DD or MM-DD-YY.
Any ideas? Thanks!

Issue with date when migrating databases between SQL Server 2008 and 2012 [duplicate]

I have the following piece of inline SQL that I run from a C# windows service:
UPDATE table_name SET
status_cd = '2',
sdate = CAST('03/28/2011 18:03:40' AS DATETIME),
bat_id = '33acff9b-e2b4-410e-baaf-417656e3c255',
cnt = 1,
attempt_date = CAST('03/28/2011 18:03:40' AS DATETIME)
WHERE id = '1855'
When I run this against a SQL Server database from within the application, I get the following error:
System.Data.SqlClient.SqlException: The conversion of a varchar data type to a datetime data type resulted in an out-of-range value.
The statement has been terminated.
But if I take the piece of SQL and run it from SQL Management Studio, it will run without issue.
Any ideas what may be causing this issue?
Ambiguous date formats are interpreted according to the language of the login. This works
set dateformat mdy
select CAST('03/28/2011 18:03:40' AS DATETIME)
This doesn't
set dateformat dmy
select CAST('03/28/2011 18:03:40' AS DATETIME)
If you use parameterised queries with the correct datatype you avoid these issues. You can also use the unambiguous "unseparated" format yyyyMMdd hh:mm:ss
But if i take the piece of sql and run it from sql management studio, it will run without issue.
If you are at liberty to, change the service account to your own login, which would inherit your language/regional perferences.
The real crux of the issue is:
I use the following to convert -> date.Value.ToString("MM/dd/yyyy HH:mm:ss")
Please start using parameterized queries so that you won't encounter these issues in the future. It is also more robust, predictable and best practice.
I think the best way to work with dates between C# and SQL is, of course, use parametrized queries, and always work with DateTime objects on C# and the ToString() formating options it provides.
You better execute set datetime <format> (here you have the set dateformat explanation on MSDN) before working with dates on SQL Server so you don't get in trouble, like for example set datetime ymd. You only need to do it once per connection because it mantains the format while open, so a good practice would be to do it just after openning the connection to the database.
Then, you can always work with 'yyyy-MM-dd HH:mm:ss:ffff' formats.
To pass the DateTime object to your parametrized query you can use DateTime.ToString('yyyy-MM-dd HH:mm:ss:ffff').
For parsing weird formatted dates on C# you can use DateTime.ParseExact() method, where you have the option to specify exactly what the input format is: DateTime.ParseExact(<some date string>, 'dd/MM-yyyy',CultureInfo.InvariantCulture). Here you have the DateTime.ParseExact() explanation on MSDN)
It's a date format issue. In Ireland the standard date format for the 28th of March would be "28-03-2011", whereas "03/28/2011" is the standard for the USA (among many others).
I know that this solution is a little different from the OP's case, but as you may have been redirected here from searching on google the title of this question, as I did, maybe you're facing the same problem I had.
Sometimes you get this error because your date time is not valid, i.e. your date (in string format) points to a day which exceeds the number of days of that month!
e.g.: CONVERT(Datetime, '2015-06-31') caused me this error, while I was converting a statement from MySql (which didn't argue! and makes the error really harder to catch) to SQL Server.
You could use next function to initialize your DateTime variable:
DATETIMEFROMPARTS ( year, month, day, hour, minute, seconds, milliseconds )
JAVA8: Use LocalDateTime.now().toString()
i faced this issue where i was using SQL it is different from MYSQL
the solution was puting in this format:
=date('m-d-y h:m:s');
rather than
=date('y-m-d h:m:s');

When to use timestamp in sql 2008?

I read several times to convert the timestamp to any readable format but I am not able to decide when to use timestamp datatype or datetime datatype to keep track of records inserted or updated in database in sql server 2008.
timestamp is deprecated, do not use this type. Its role has been replaced by the rowversion type, which is a synonym for timestamp:
The timestamp syntax is deprecated.
This feature will be removed in a
future version of Microsoft SQL
Server. Avoid using this feature in
new development work, and plan to
modify applications that currently use
this feature.
As a type, timestamp (and rowversion) has absolutely no relation to dates, time or anything chronological:
The rowversion data type is just an
incrementing number and does not
preserve a date or a time.
If you need to track the time when a record was inserted or updated, use DATETIME2, at the desired precission.
Read detailed msdn article here
hope this will help you.

Cast Date in Informix

I have never used Informix before and I'm trying to write a query that will return records over the last 365 days.
Here is the query I have been trying to use:
Select * from Visit where vis_mod_dt between today-365 and today;
That returns no records even though I know that there is data for the last 365 days. I am guessing that the vis_mod_dt in not a true date column, although it displays as '12/31/1899' I have tried to cast this column using:
select * from visit where date(vis_mod_dt) between today-365 and today;
This still returns no data.
Any ideas?
Informix DATE format
Be aware that the date 1899-12-31 corresponds to the internal date representation of zero (0). That is, internally, Informix stores DATE values in a 4-byte integer, and counts the number of days since 1899-12-31, so Day 1 was 1900-01-01 (and since it knows that 1900 was not a leap year, Day 60 was 1900-03-01).
That fact makes me worry about what is in your table. However, if the data in your table cannot be converted to a DATE upon request, normally you would get an error.
What is your table schema?
It would be sensible for you to establish the schema either using DB-Access and the Info/Tables option, or use DB-Schema:
dbschema -d dbase -t visit
The DB-Schema output is more suitable for adding to your question.
The query expressions using 'TODAY-365' and 'TODAY' should work fine - if there is data to select.
DBDATE environment variable
There is an environment variable, DBDATE, that you may need to set to get things to work - to convert from a string representation to dates. Since you are probably based in the UK (from your icon), then you may want and need to set the value of DBDATE to:
export DBDATE=DMY4/
This says that dates consist of the day, the month, a 4-digit year and the '/' is used as the preferred separator. You won't be surprised to learn that the presumed default value is usually 'MDY4/', for US format; I use 'Y4MD-' habitually, so I see DATE value the same as DATETIME YEAR TO DAY, which is the ISO 8601:2004 notation for a date. (It has many benefits: it is unambiguous, and naive sorting algorithms sort such dates into date order.) There's actually a lot of mechanism in the background in IDS (IBM Informix Dynamic Server - which, I assume, is the DBMS that you are using; there are some alternatives that are also Informix DBMS) such that strings with 2-digit dates will usually be converted correctly (but they are ambiguous and undesirable), and separators other than '/' will be recognized on input, but the slash will be used on 'output' (when converting DATE to string).
Information needed to improve the answer to this question - 1st Edition.
If what is here does not help, then I recommend editing your question to include:
The table schema.
A few (2-4) rows of data that you think should be selected but aren't.
Platform and version information. It can help to have the version down to the level of detail of IDS 11.50.FC4W1; occasionally it matters. Most usually, the first three digits are what affect things, of course.
If your table is big (many columns), try to select the key columns (vis_mod_dt is by far the most important one). Ideally, you won't need any scroll bars in the display.
Make sure you don't include any sensitive information.
Information needed to improve the answer to this question - 2nd Edition
I will help you if you pay attention to the questions I ask you. I cannot help you if you do not pay attention to the questions I ask. And please edit your question rather than adding information as an 'answer'.
What is the table schema? What is the output from:
SELECT t.tabid, t.tabname, c.colno, c.colname, c.coltype, c.collength
FROM "informix".systables AS t, "informix".syscolumns AS c
WHERE t.tabid = c.tabid
AND t.tabname = "visit"
ORDER BY t.tabid, c.colno;
What do you get from:
SELECT TODAY, TODAY-365 FROM "informix".systables WHERE tabid = 1;
Do you have the environment variable DBDATE set? If so, what is its value?
Do you have the environment variables CLIENT_LOCALE or DB_LOCALE set? If so, what are their values?
Which version of Informix are you using?
Which platform are you using it on?
Which language or tool are you using to run the query.
Note: if you cannot copy'n'paste the queries above, then you probably do not need to include the quoted '"informix".' attributes on the system catalog; however, as written, the queries will work on any extant Informix database - OnLine 5.x, SE 5.x or 7.x, IDS 7.x, XPS 8.x, IDS 9.x or 10.x or 11.x - and any mode of database (unlogged, logged, MODE ANSI). I'd use the JOIN notation except that some of the older versions don't support it - though you have to be on very old versions for that to be a problem.
This is a little confusing, because when I run the following, I get data:
select count(*) from visit where vis_mod_dt between "10/01/2008" and "10/01/2009"
how about unloading the table to ascii file, examine the unloaded vis_mod_dt values to see if they conform to DBDATE=MDY4 (mmddyyyy) format?.. if they do, ALTER vis_mod_dt to TYPE DATE if it's not a DATE column, then LOAD the unloaded table back in.
the: "BETWEEN today-365 AND today" part of your SELECT statement works for me in my apps.

Get UTC date out of SQL Server & show in grid as local time

I've got a table in SQL Server 2005 that has a datetime column holding dates in UTC form. I want clients to call the a .NET server app and the server will return a DataTable with records to be bound client side to a DataGridView.
** On the client the dates should be displayed in local time **, clients will be in may regions of the world.
Does anyone have any tips on achieving this?
I could of course add a few lines to loop through and update the dates in the table before display but I can't help feeling there's got to be some snazzy funky way of doing this.
TA!!
DateTime.ToLocalTime Is what you're looking for.
Essentially, the fact that you're calling the method tells the DateTime object to add the current culture's offset from UTC and return the result. DateTime.ToUniversalTime does the opposite.
First of all, make sure that the DATETIME values in your tables are stored as UTC values.
After that when you read them, the "client" application can convert them to local datetime (whatever that may be).
When inserting/updating stuff make sure you convert from local to utc before storing in the db.

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