According to [the documentation][1], `timestamp` is a synonym for `rowversion` - it&#39;s automatically generated and *guaranteed*&lt;sup&gt;1&lt;/sup&gt; to be unique. `datetime` isn&#39;t - it&#39;s just a data type which handles dates and times, and can be client-specified on insert etc.

----

&lt;sup&gt;1&lt;/sup&gt; Assuming you use it properly, of course. See comments.

  [1]: http://msdn.microsoft.com/en-us/library/ms182776.aspx

Datetime is a datatype.

Timestamp is a method for row versioning. In fact, in sql server 2008 this column type was renamed (i.e. timestamp is deprecated) to rowversion. It basically means that every time a row is changed, this value is increased. This is done with a database counter which automatically increase for every inserted or updated row.

For more information:

http://www.sqlteam.com/article/timestamps-vs-datetime-data-types

http://msdn.microsoft.com/en-us/library/ms182776.aspx

I have a really simple question but it&#39;s something I have not done before. I have the following:

    &lt;td id=&quot;abc&quot; style=&quot;width:15px;&quot;&gt;&lt;span&gt;&lt;/span&gt;&lt;/td&gt;

I would like to put some text into the span. 

How can I do this with jQuery. I know how to change things with the id of abc but not the code inside the span. 

thanks,

How can I change the text inside my &lt;span&gt; with jQuery?

I came across some code containing the following:

    struct ABC {
        unsigned long array[MAX];
    } abc;

When does it make sense to use a declaration like this?

Why declare a struct that only contains an array in C?

What is the difference between `Timestamp` and `Datetime` SQL Server?

I thought Both formats are capable of storing date + time. Then, Where the difference is lying between them?

But `Timestamp` is not capable of storing date, time information.

Still Whats the difference?

Difference between datetime and timestamp in sqlserver?

What is the difference between <code>Timestamp</code> and <code>Datetime</code> SQL Server?
I thought Both formats are capable of storing date + time. Then, Where the difference is lying between them?
But <code>Timestamp</code> is not capable of storing date, time information.
Still Whats the difference?

I&#39;m a bit old school when it comes to database design, so I&#39;m totally for using the correct data sizes in columns. However, when reviewing a database for a friend, I noticed he used `varchar(max)` a lot.  Now, my immediate thought was to throw it back to him and tell him to change it.  But then I thought about it and couldn&#39;t come up with a good reason for him not to use it (he&#39;d used a case type tool to generate the db, if you&#39;re wondering).

I&#39;ve been researching the topic of `varchar(max)` usage and I can&#39;t really come up with any good reason for him not to use it.

He doesn&#39;t use the columns for indexes, the application that sits on the db has limitations on the input, so it won&#39;t allow massive entries in the fields.

Any help would be appreciated to help me make him see the light :).

Why not use varchar(max)?

I am not a database expert and have no formal computer science background, so bear with me.  I want to know the kinds of _real world_ negative things that can happen if you use an old [MongoDB version prior to v4](https://www.mongodb.com/transactions), which were not [ACID](http://en.wikipedia.org/wiki/ACID) compliant.  This applies to any ACID noncompliant database.

I understand that MongoDB can perform [Atomic Operations](http://www.mongodb.org/display/DOCS/Atomic+Operations), but that they don&#39;t &quot;support traditional locking and complex transactions&quot;, mostly for performance reasons.  I also understand the importance of database transactions, and the example of when your database is for a bank, and you&#39;re updating several records that all need to be in sync, you want the transaction to revert back to the initial state if there&#39;s a power outage so credit equals purchase, etc.

But when I get into conversations about MongoDB, those of us that don&#39;t know the technical details of how databases are actually implemented start throwing around statements like:

&gt; MongoDB is way faster than MySQL and Postgres, but there&#39;s a tiny chance, like 1 in a million, that it &quot;won&#39;t save correctly&quot;.

That &quot;won&#39;t save correctly&quot; part is referring to this understanding: If there&#39;s a power outage right at the instant you&#39;re writing to MongoDB, there&#39;s a chance for a particular record (say you&#39;re tracking pageviews in documents with 10 attributes each), that one of the documents only saved 5 of the attributes… which means over time your pageview counters are going to be &quot;slightly&quot; off.  You&#39;ll never know by how much, you know they&#39;ll be 99.999% correct, but not 100%.  This is because, unless you specifically made this a [mongodb atomic operation](http://www.mongodb.org/display/DOCS/Atomic+Operations), the operation is not guaranteed to have been atomic.

So my question is, what is the correct interpretation of when and why MongoDB may not &quot;save correctly&quot;?  What parts of ACID does it not satisfy, and under what circumstances, and how do you know when that 0.001% of your data is off?  Can&#39;t this be fixed somehow?  If not, this seems to mean that you shouldn&#39;t store things like your `users` table in MongoDB, because a record might not save.  But then again, that 1/1,000,000 user might just need to &quot;try signing up again&quot;, no?

I am just looking for maybe a list of when/why negative things happen with an ACID noncompliant database like MongoDB, and ideally if there&#39;s a standard workaround (like run a background job to cleanup data, or only use SQL for this, etc.).

What did MongoDB not being ACID compliant before v4 really mean?

I am using a SQL 2008 database project (in visual studio) to manage the schema and initial test data for my project. The atabase project uses a post deployment which includes a number of other scripts using SQLCMD&#39;s &quot;:r &lt;filename&gt;&quot; syntax.

I would like to be able to conditionally include certain files based on a SQLCMD variable. This will allow me to run the project several times with our nightly build to setup various version of the database with different configurations of the data (for a multi-tenant system).

I have tried the following:

    IF (&#39;$(ConfigSetting)&#39; = &#39;Configuration1&#39;)
      BEGIN
        print &#39;inserting specific configuration&#39; 
    :r .\Configuration1\Data.sql
      END
    ELSE
      BEGIN
        print &#39;inserting generic data&#39; 
    :r .\GenericConfiguration\Data.sql
      END

But I get a compilation error: 
**SQL01260: A fatal parser error occurred: Script.PostDeployment.sql**

Has anyone seen this error or managed to configure their postdeployment script to be flexible in this way? Or am I going about this in the wrong way completely?

Thanks,
Rob

P.S. I&#39;ve also tried changing this around so that the path to the file is a variable, [similar to this post][1]. But this gives me an error saying that the path is incorrect.


  [1]: https://stackoverflow.com/questions/5653103/sqlcmd-r-path-where-path-is-a-variable
  

Conditional logic in PostDeployment.sql script using SQLCMD

I have a table named `PAYMENT`. Within this table I have a user ID, an account number, a ZIP code and a date. I would like to find all records for all users that have more than one payment per day with the same account number. 

**UPDATE:** Additionally, there should be a filter than only counts the records whose ZIP code is different.

This is how the table looks like:

&lt;pre&gt;| user_id | account_no | zip   |      date |
|       1 |        123 | 55555 | 12-DEC-09 | 
|       1 |        123 | 66666 | 12-DEC-09 |
|       1 |        123 | 55555 | 13-DEC-09 |
|       2 |        456 | 77777 | 14-DEC-09 |
|       2 |        456 | 77777 | 14-DEC-09 |
|       2 |        789 | 77777 | 14-DEC-09 |
|       2 |        789 | 77777 | 14-DEC-09 |
&lt;/pre&gt; 

The result should look similar to this:

&lt;pre&gt;| user_id | count |
|       1 |     2 |
&lt;/pre&gt; 

How would you express this in a SQL query? I was thinking self join but for some reason my count is wrong.

SQL query for finding records where count &gt; 1

Entering the following command into a PostgreSQL interactive terminal results in an error:

    ALTER TABLE tbl_name ALTER COLUMN col_name varchar (11);

What is the correct command to alter the data type of a column?


How to alter a column&#39;s data type in a PostgreSQL table?

I have a table of data (the db is MSSQL):

    ID  OrderNO  PartCode  Quantity DateEntered
    417 2144     44917     100      18-08-11
    418 7235     11762     5        18-08-11
    419 9999     60657     100      18-08-11
    420 9999     60657     90       19-08-11

I would like to make a query that returns OrderNO, PartCode and Quantity, but only for the last registered order.

From the example table I would like to get back the following info:

     OrderNO  PartCode  Quantity     
     2144     44917     100      
     7235     11762     5        
     9999     60657     90  

Notice that only one line was returned for order 9999.

Thanks!

SQL Server: SELECT only the rows with MAX(DATE)

I have query in a stored procedure that calls some linked servers with some dynamic SQL. I understand that EF doesn&#39;t like that, so I specifically listed all the columns that would be returned. Yet, it still doesn&#39;t like that. What am I doing wrong here? I just want EF to be able to detect the columns returned from the stored procedure so I can create the classes I need.

Please see the following code that makes up the last lines of my stored procedure:

    SELECT
	    #TempMain.ID,
	    #TempMain.Class_Data,
	    #TempMain.Web_Store_Class1,
	    #TempMain.Web_Store_Class2,
	    #TempMain.Web_Store_Status,
	    #TempMain.Cur_1pc_Cat51_Price,
	    #TempMain.Cur_1pc_Cat52_Price,
    	#TempMain.Cur_1pc_Cat61_Price,
	    #TempMain.Cur_1pc_Cat62_Price,
	    #TempMain.Cur_1pc_Cat63_Price,
	    #TempMain.Flat_Length,
	    #TempMain.Flat_Width,
	    #TempMain.Item_Height,
	    #TempMain.Item_Weight,
	    #TempMain.Um,
	    #TempMain.Lead_Time_Code,
	    #TempMain.Wp_Image_Nme,
	    #TempMain.Wp_Mod_Dte,
	    #TempMain.Catalog_Price_Chg_Dt,
	    #TempMain.Description,
	    #TempMain.Supersede_Ctl,
	    #TempMain.Supersede_Pn,
    	TempDesc.Cust_Desc,
	    TempMfgr.Mfgr_Item_Nbr,
	    TempMfgr.Mfgr_Name,
	    TempMfgr.Vendor_ID
    FROM
    	#TempMain
    		LEFT JOIN TempDesc ON #TempMain.ID = TempDesc.ID
		    LEFT JOIN TempMfgr ON #TempMain.ID = TempMfgr.ID

EF4 - The selected stored procedure returns no columns

I am trying to group records by week, storing the aggregated date as the first day of the week. However, the standard technique I use for rounding off dates does not appear to work correctly with weeks (though it does for days, months, years, quarters and any other timeframe I&#39;ve applied it to).

Here is the SQL:

    select &quot;start_of_week&quot; = dateadd(week, datediff(week, 0, getdate()), 0);

This returns `2011-08-22 00:00:00.000`, which is a Monday, not a Sunday. Selecting `@@datefirst` returns `7`, which is the code for Sunday, so the server is setup correctly in as far as I know.

I can bypass this easily enough by changing the above code to:

    select &quot;start_of_week&quot; = dateadd(week, datediff(week, 0, getdate()), -1);

But the fact that I have to make such an exception makes me a little uneasy. Also, apologies if this is a duplicate question. I found some related questions but none that addressed this aspect specifically.

Get first day of week in SQL Server

How to write literal boolean value in SQL Server? See sample use:

    select * from SomeTable where PSEUDO_TRUE

another sample:

    if PSEUDO_TRUE
    begin
      select &#39;Hello, SQL!&#39;
    end 

Note: The query above has nothing to do with how I&#39;m going to use it. It is just to test the literal boolean.

SQL Server - boolean literal?

`@RowFrom int`

`@RowTo int`

are both Global Input Params for the Stored Procedure, and since I am compiling the SQL query inside the Stored Procedure with T-SQL then using `Exec(@sqlstatement)` at the end of the stored procedure to show the result, it gives me this error when I try to use the `@RowFrom` or `@RowTo` inside the `@sqlstatement` variable that is executed.. it works fine otherwise.. please help.

    &quot;Must declare the scalar variable &quot;@RowFrom&quot;.&quot;

------------------------

Also, I tried including the following in the `@sqlstatement` variable:

    &#39;Declare @Rt int&#39;
    &#39;SET @Rt = &#39; + @RowTo

but `@RowTo` still doesn&#39;t pass its value to `@Rt`  and generates an error.


Must declare the scalar variable

The date string looks like this

`2011-08-19 17:14:40`

(year-month-day  hours:minutes:seconds)


How can I find out if the date is older than the current date with more than 30 days?

find if date is older than 30 days

How can I find out the min and the max date from an array of dates? Currently, I am creating an array like this:

    var dates = [];
    dates.push(new Date(&quot;2011/06/25&quot;))
    dates.push(new Date(&quot;2011/06/26&quot;))
    dates.push(new Date(&quot;2011/06/27&quot;))
    dates.push(new Date(&quot;2011/06/28&quot;))

Is there a built-in function to do this or am I to write my own?

Min/Max of dates in an array?

i am trying to convert a string in the format dd-mm-yyyy into a date object in JavaScript using the following:

     var from = $(&quot;#datepicker&quot;).val();
     var to = $(&quot;#datepickertwo&quot;).val();
     var f = new Date(from);
     var t = new Date(to);

`(&quot;#datepicker&quot;).val()` contains a date in the format dd-mm-yyyy. 
When I do the following, I get &quot;Invalid Date&quot;:

    alert(f);

Is this because of the &#39;-&#39; symbol? How can I overcome this?




Convert dd-mm-yyyy string to date

How do I get the month as an integer from a Date object (`java.util.Date`)?

Java: Get month Integer from Date

Lets say I have an array as:

`int a[]={4,5,7,10,2,3,6}`

when I access an element, such as `a[3]`, what does actually happen behind the scenes?
Why do many algorithm books (such as the Cormen book...) say that it takes a constant time? 

(I&#39;m just a noob in low-level programming so I would like to learn more from you guys)

why does accessing an element in an array take constant time?

Is there a simple way / module to _correctly_ measure the elapsed time in python? I know that I can simply call `time.time()` twice and take the difference, but that will yield wrong results if the system time is changed. Granted, that doesn&#39;t happen very often, but it does indicate that I&#39;m measuring the wrong thing.

Using `time.time()` to measure durations is incredibly roundabout when you think about it. You take the difference of two absolute time measurements which are in turn constructed from duration measurements (performed by timers) and known absolute times (set manually or via ntp), that you aren&#39;t interested in at all.

So, is there a way to query this &quot;timer time&quot; directly? I&#39;d imagine that it can be represented as a millisecond or microsecond value that has no meaningful absolute representation (and thus doesn&#39;t need to be adjusted with system time). Looking around a bit it seems that this is exactly what `System.nanoTime()` does in Java, but I did not find a corresponding Python function, even though it should (hardware-technically) be easier to provide than `time.time()`.

Edit: To avoid confusion and address the answers below: This is not about DST changes, and I don&#39;t want CPU time either - I want elapsed physical time. It doesn&#39;t need to be very fine-grained, and not even particularly accurate. It just shouldn&#39;t give me negative durations, or durations which are off by several orders of magnitude (above the granularity), just because someone decided to set the system clock to a different value. Here&#39;s what the Python docs say about &#39;time.time()&#39;:

[&quot;While this function normally returns non-decreasing values, it can return a lower value than a previous call if the system clock has been set back between the two calls&quot;][1]

This is exactly what I want to avoid, since it can lead to strange things like negative values in time calculations. I can work around this at the moment, but I believe it is a good idea to learn using the proper solutions where feasible, since the kludges will come back to bite you one day.

Edit2: Some research shows that you can get a system time independent measurement like I want in Windows by using GetTickCount64(), under Linux you can get it in the return value of times(). However, I still can&#39;t find a module which provides this functionality in Python.

  [1]: http://docs.python.org/library/time.html#time.time

Measuring elapsed time in python

I am trying to figure out the differences between the `datetime` and `time` modules, and what each should be used for.

I know that `datetime` provides both dates and time.  What is the use of the `time` module?

Examples would be appreciated and differences concerning timezones would especially be of interest.

Difference between Python datetime vs time modules

I learning about some basic C functions and have encountered `time(NULL)` in some manuals.

What exactly does this mean?

Content Type	Original Author	Original Content on Stackoverflow
Question	MduSenthil	View Question on Stackoverflow
Solution 1 - Sql	Jon Skeet	View Answer on Stackoverflow
Solution 2 - Sql	Andreas Ågren	View Answer on Stackoverflow

Difference between datetime and timestamp in sqlserver?

Sql Problem Overview

Sql Solutions

Solution 1 - Sql

Solution 2 - Sql

Why declare a struct that only contains an array in C?

How can I change the text inside my <span> with jQuery?

Attributions