When to use timestamp in sql 2008? - asp.net

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 Its role has been replaced by the rowversion type, which is a synonym for timestamp: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.

Related

Unparseable Date in Grails Domain Class from SQLite Database

I have a sqlite db (it is the spiceworks db) and I am mapping the tables to grails domain classes. There is a table in particular that is in a datetime format (yyyy-MM-dd HH:mm:ss). An example of such a date in the db for anyone who wants to verify would be: 2015-06-26 15:32:39
I created the domain class and mapped my properties to the columns. Let grails generate the views so that they are default. When I try to get to the index page I get:
URI
/spiceworks/weeklyReportItem
Class
java.text.ParseException
Message
Unparseable date: "2015-06-26 15:32:39" does not match (\p{Nd}++)\Q-\E(\p{Nd}++)\Q-\E(\p{Nd}++)\Q \E(\p{Nd}++)\Q:\E(\p{Nd}++)\Q:\E(\p{Nd}++)\Q.\E(\p{Nd}++)
I've used MSSQL datetimes in the past and have never ran into this issue. In the database, the data type for the problematic column is datetime. Anyone know what's going on?
EDIT: I only have Read permissions on the db and the spiceworks source code isn't open source.
If you look at that regular expression, you'll see it's looking for a ISO8601 timestamp formatted like YYYY-MM-DD HH:mm:SS.SSS - in other words, it needs a decimal seconds, and you're just providing whole seconds.
An easy fix would be to update every existing value in the relevant column by appending '.000' to it, and update the insertion routines to do the same.
If you refer to the sqlite date time functions, there's a %f format specifier for strftime() that can be used to produce fractional seconds that might be helpful if you're building the timestamp directly in an insert query.
In the database, the data type for the problematic column is datetime
Sqlite3 doesn't have a datetime type. The timestamps you're storing are strings. More information.

How to get current date time format in SQlite?

I am using sqlite for local database in mobile and in my database. i want to know that
How to get current date format in SQLITE? I want to get date in the next format: MM/dd/yyyy
To get the current date you can use:
SELECT date('now');
Note: This is NOT a server date, it's the same time you get if you query the date and time directly from your application because SQLITE runs in-process.
It's mostly useful for putting a current time into a table or for some simple calculations if your language's date processing is very poor.
To do the calculations see the SQLITE Documentation
See the docs for formatting too for example:
SELECT strftime('%Y-%m-%d %H:%M:%S', datetime('now'))
According to the SQLite documentation as of this writing (3/30/2020), in the section titled "The DEFAULT clause", it is recommended that a constant value be used instead of a sub-query.
In my experimentation, I also ran into issues with the SQLite CREATE TABLE statement that was generated during model creation by EF Core 3.0 when using SELECT datetime('now'). The SQLite data provider complained of a syntax error when using a SELECT statement within the CREATE table statement. As such, I would recommend using the CURRENT_TIMESTAMP keyword.
for your concrete case, this is what you need:
strftime('%m/%d/%Y',date('now'))

Updating an SQLite database via an ODBC linked table in Access

I am having an issue with an SQLite database. I am using the SQLite ODBC from http://www.ch-werner.de/sqliteodbc/ Installed the 64-bit version and created the ODBC with these settings:
I open my Access database and link to the datasource. I can open the table, add records, but cannot delete or edit any records. Is there something I need to fix on the ODBC side to allow this? The error I get when I try to delete a record is:
The Microsoft Access database engine stopped the process because you and another user are attempting to change the same data at the same time.
When I edit a record I get:
The record has been changed by another user since you started editing it. If you save the record, you will overwrite the changed the other user made.
Save record is disabled. Only copy to clipboard or drop changes is available.
My initial attempt to recreate your issue was unsuccessful. I used the following on my 32-bit test VM:
Access 2010
SQLite 3.8.2
SQLite ODBC Driver 0.996
I created and populated the test table [tbl1] as documented here. I created an Access linked table and when prompted I chose both columns ([one] and [two]) as the Primary Key. When I opened the linked table in Datasheet View I was able to add, edit, and delete records without incident.
The only difference I can see between my setup and yours (apart from the fact that I am on 32-bit and you are on 64-bit) is that in the ODBC DSN settings I left the Sync.Mode setting at its default value of NORMAL, whereas yours appears to be set to OFF.
Try setting your Sync.Mode to NORMAL and see if that makes a difference.
Edit re: comments
The solution in this case was the following:
One possible workaround would be to create a new SQLite table with all the same columns plus a new INTEGER PRIMARY KEY column which Access will "see" as AutoNumber. You can create a unique index on (what are currently) the first four columns to ensure that they remain unique, but the new new "identity" (ROWID) column is what Access would use to identify rows for CRUD operations.
I had this problem too. I have a table with a primary key on a VARCHAR(30) (TEXT) field.
Adding an INTEGER PRIMARY KEY column didn't help at all. After lots of testing I found the issue was with a DATETIME field I had in the table. I removed the DATETIME field and I was able to update record values in MS-Access datasheet view.
So now any DATETIME fields I need in SQLite, I declare as VARCHAR(19) so they some into Access via ODBC as text. Not perfect but it works. (And of course SQLite doesn't have a real DATETIME field type anyway so TEXT is just fine and will convert OK)
I confirmed it's a number conversion issue. With an empty DATETIME field, I can add a time of 01-01-2014 12:01:02 via Access's datasheet view, if I then look at the value in SQLite the seconds have been rounded off:
sqlite> SELECT three from TEST where FLoc='1020';
2014-01-01 12:01:00.000
SYNCMODE should also be NORMAL not OFF.
Update:
If you have any text fields with a defined length (e.g. foo VARCHAR(10)) and the field contents contains more characters than the field definition (which SQLite allows) MS-Access will also barf when trying to update any of the fields on that row.
I've searched all similar posts as I had a similar issue with SQLite linked via ODBC to Access. I had three tables, two of them allowed edits, but the third didn't. The third one had a DATETIME field and when I changed the data type to a TEXT field in the original SQLite database and relinked to access, I could edit the table. So for me it was confirmed as an issue with the DATETIME field.
After running into this problem, not finding a satisfactory answer, and wasting a lot of time trying other solutions, I eventually discovered that what others have mentioned about DATETIME fields is accurate but another solution exists that lets you keep the proper data type. The SQLite ODBC driver can convert Julian day values into the ODBC SQL_TIMESTAMP / SQL_TYPE_TIMESTAMP types by looking for floating point values in the column, if you have that option enabled in the driver. Storing dates in this manner gives the ODBC timestamp value enough precision to avoid the write conflict error, as well as letting Access see the column as a date/time field.
Even storing sub-second precision in the date string doesn't work, which is possibly a bug in the driver because the resulting TIMESTAMP_STRUCT contains the same values, but the fractional seconds must be lost elsewhere.

How to add Timestamp value in SQL Server 2005 by using LINQ

My database table have a Timestamp column named as inTime and i am using LINQ for insert, update data in SQL server. Now i want to add the timestamp value in my database but i don't know how to insert?
spaBL.attendance obj = new spaBL.attendance();
obj.FK_employeeId = 1;
obj.inTime =[what to write here??]
inTime is of timestamp type.
Timestamp as in SQL Server Timestamp data type?
;) If I got a cent every time someone did not read the documentation and thought that is a TIME STAMP I would be more rich than bill gates.
Timestamp data time has NO TIME INFORMATION IN IT. It is a running version number, legacy to Sybase SQL Server where SQL Server from Microsoft originated and a totally borked design.
So, no, you CAN NOT SET THAT FIELD, sorry, and it has no usable value except to see whether it changed (then the row was updated).
The documentation is explicitly clear on that, even if some people think reading is maybe a lost art:
http://msdn.microsoft.com/en-us/library/ms182776(v=sql.90).aspx
Is a data type that exposes automatically generated, unique binary
numbers within a database. timestamp is generally used as a mechanism
for version-stamping table rows.
There is no way for you to set it. CHange your LINQ setup to not update this column.
Timestamp values are auto generated by the server on inserts. You should insert rows to the table without supplying a value for the timestamp column. Sql server will then generate the value for the column.
Note the columns of type timestamp does NOT contain values that can be parsed as a DateTime. The idea behind timestamp columns is that they can be used to check if a row has been updated between fetching the row and trying to update the row with new values.
You do not provide values for columns with a Timestamp (Rowversion) data type. SQL Server will provide a value for you automatically (and it won't be a datetime value). Therefore you do not need to be concerned with having Linq To SQL insert a Timestamp value for you. In fact, you cannot do it. SQL Server will do it for you. You can however, retrieve the value of a Timestamp column. I believe the corresponding C# type will be System.Data.Linq.Binary.
How to add Timestamp value in SQL database by using LINQ
hope it helps
You cannot update a timestamp. See here. And indeed, as TomTom indicated, it doesn't contain actual time information.

SQL Server 2005 vs. ASP.net datetime format confusion

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.

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