`SYSTEM_USER` returns the current executing context, so this can return an impersonated context

`ORIGINAL_LOGIN()` returns the identity of the user that initially connected to the instance, so regardless whether the context is impersonated or not it will yield the original user that logged in, good for auditing.

`SUSER_SNAME()` this is used if you want to get the username by SID so `SUSER_SNAME` can be invoked with a parameter like such `SUSER_SNAME([server_user_sid])` but the SID is optional if you don’t pass that parameter the  current user is returned.


I need some sort of way to store key/value pairs where the value can be of different types.

So I like to do:

     int i = 12;
     string s = &quot;test&quot;;
     double x = 24.1;
    
     Storage.Add(&quot;age&quot;, i);
     Storage.Add(&quot;name&quot;, s);
     Storage.Add(&quot;bmi&quot;, x);

And later retrieve the values with:

     int a = Storage.Get(&quot;age&quot;);
     string b = Storage.Get(&quot;name&quot;);
     double c = Storage.Get(&quot;bmi&quot;);

How should a Storage like this look like?
Thanks,
Erik

How do I create a Dictionary that holds different types in C#

This question requires some hypothetical background. Let&#39;s consider an `employee` table that has columns `name`, `date_of_birth`, `title`, `salary`, using MySQL as the RDBMS. Since if any given person has the same name and birth date as another person, they are, by definition, the same person (barring amazing coincidences where we have two people named Abraham Lincoln born on February 12, 1809), we&#39;ll put a unique key on `name` and `date_of_birth` that means &quot;don&#39;t store the same person twice.&quot; Now consider this data:

    id name        date_of_birth title          salary
     1 John Smith  1960-10-02    President      500,000
     2 Jane Doe    1982-05-05    Accountant      80,000
     3 Jim Johnson NULL          Office Manager  40,000
     4 Tim Smith   1899-04-11    Janitor         95,000

If I now try to run the following statement, it should and will fail:

    INSERT INTO employee (name, date_of_birth, title, salary)
    VALUES (&#39;Tim Smith&#39;, &#39;1899-04-11&#39;, &#39;Janitor&#39;, &#39;95,000&#39;)

If I try this one, it will succeed:

    INSERT INTO employee (name, title, salary)
    VALUES (&#39;Jim Johnson&#39;, &#39;Office Manager&#39;, &#39;40,000&#39;)

And now my data will look like this:

    id name        date_of_birth title          salary
     1 John Smith  1960-10-02    President      500,000
     2 Jane Doe    1982-05-05    Accountant      80,000
     3 Jim Johnson NULL          Office Manager  40,000
     4 Tim Smith   1899-04-11    Janitor         95,000
     5 Jim Johnson NULL          Office Manager  40,000

This is not what I want but I can&#39;t say I entirely disagree with what happened. If we talk in terms of mathematical sets,

    {&#39;Tim Smith&#39;, &#39;1899-04-11&#39;} = {&#39;Tim Smith&#39;, &#39;1899-04-11&#39;} &lt;-- TRUE
    {&#39;Tim Smith&#39;, &#39;1899-04-11&#39;} = {&#39;Jane Doe&#39;, &#39;1982-05-05&#39;} &lt;-- FALSE
    {&#39;Tim Smith&#39;, &#39;1899-04-11&#39;} = {&#39;Jim Johnson&#39;, NULL} &lt;-- UNKNOWN
    {&#39;Jim Johnson&#39;, NULL} = {&#39;Jim Johnson&#39;, NULL} &lt;-- UNKNOWN

My guess is that MySQL says, &quot;Since I don&#39;t *know* that Jim Johnson with a `NULL` birth date isn&#39;t already in this table, I&#39;ll add him.&quot;

My question is: **How can I prevent duplicates even though `date_of_birth` is not always known?** The best I&#39;ve come up with so far is to move `date_of_birth` to a different table. The problem with that, however, is that I might end up with, say, two cashiers with the same name, title and salary, different birth dates and no way to store them both without having duplicates.

Unique key with NULLs

Which one should I use to record update made by users?

1. `SYSTEM_USER`, or
2. `ORIGINAL_LOGIN()`, or
3. `SUSER_SNAME()`

SQL Server - current user name

<p>Which one should I use to record update made by users?</p>
<ol>
<li><code>SYSTEM_USER</code>, or</li>
<li><code>ORIGINAL_LOGIN()</code>, or</li>
<li><code>SUSER_SNAME()</code></li>
</ol>


I have a table Administrator with only one column, adminId which is the primary-key. Because of business rules it has to be this way. 

I&#39;d like to understand once and for all how I can write stored procedures that insert values in tables like this. I am using SQL Server and T-SQL and tried using SCOPE_IDENTITY() but that doesn&#39;t work since the table has INSERT_IDENTITY to false or off.

I&#39;d really like to not insert a dummy value just to be able to insert a new row.   Thanks!

Inserting rows into a table with one IDENTITY column only

I want get the value from `Exec(@sql)` and assign to `@Rowcount(int)`

Here is my query:


    &#39;SET @RowCount = (select count(*) 
                        FROM dbo.Comm_Services 
                       WHERE CompanyId = &#39;+cast(@CompanyId as char)+&#39; and &#39;+@condition+&#39;)&#39;



Return value from exec(@sql)

I&#39;ve been given a user account to a SQL Server database that only has privileges to execute a stored procedure. I added the JTDS SQL Server JDBC jar file to SQL Developer and added it as a Third Party JDBC driver. I can successfully log in to the SQL Server database.  I was given this syntax for running the procedure:

    EXEC proc_name &#39;paramValue1&#39; &#39;paramValue2&#39;

When I run this as either a statement or a script, I get this error:

    Error starting at line 1 in command:
    EXEC proc_name &#39;paramValue1&#39; &#39;paramValue2&#39;
    Error report:
    Incorrect syntax near the keyword &#39;BEGIN&#39;.

I tried wrapping the statement in `BEGIN/END`, but get the same error.  Is it possible to call the procedure from SQL Developer?  If so, what syntax do I need to use?

How to Execute SQL Server Stored Procedure in SQL Developer?

I have users who can login on a front-end page, and admins who can login on an admin page.

Should both users and admins be &quot;Users&quot; with different roles, or should they be split in different tables?

Is it good database design to have admin users in the same table as front-end users?

This is a known question but the best solution I&#39;ve found is something like:

    SELECT TOP N *
    FROM MyTable
    ORDER BY Id DESC

I&#39;ve a table with lots of rows. It is not a posibility to use that query because it takes lot of time. So how can I do to select last N rows without using ORDER BY?

**EDIT**

Sorry duplicated question of [this one][1]


  [1]: https://stackoverflow.com/questions/311054/how-do-i-select-last-5-rows-in-a-table-without-sorting

SQL Server SELECT LAST N Rows

I&#39;m doing some basic sql on a few tables I have, using a union(rightly or wrongly)

but I need remove the duplicates. Any ideas?

    select * from calls
    left join users a on calls.assigned_to= a.user_id
    where a.dept = 4 
    union
    select * from calls
    left join users r on calls.requestor_id= r.user_id
    where r.dept = 4

remove duplicates from sql union

We&#39;re going to provide our clients with a tool that (among other things) creates a new SQL Server database, and I want to be able to do basic validation on the database name they provide. SQL Server&#39;s documentation explains what characters are valid in a database name. However, the documentation is apparently incorrect, because I can successfully create databases whose names violate the documented rules.

According to SQL Server&#39;s documentation for &lt;a href=&quot;http://msdn.microsoft.com/en-us/library/ms176061.aspx&quot;&gt;CREATE DATABASE&lt;/a&gt;, database names must comply with the rules for identifiers; and the rules for &lt;a href=&quot;http://msdn.microsoft.com/en-us/library/ms175874.aspx&quot;&gt;identifiers&lt;/a&gt; depend on the database compatibility level. When the compatibility level is 100 (which, according to SQL Server Management Studio, means &quot;SQL Server 2008&quot;), the name must start with a Unicode letter, `_`, `@`, or `#`; followed by one or more letters, numbers, `@`, `$`, `#`, or `_`. The documentation clearly states that embedded spaces or special characters are not allowed.

This flies in the face of the available evidence, because I can use SQL Server Management Studio to create a database whose name is `This &amp; That | &quot;Other&quot;` -- which not only contains embedded spaces (explicitly forbidden), but contains special characters (`|`, `&quot;`) that aren&#39;t even valid in a filename. I checked, and the database&#39;s compatibility level is indeed &quot;SQL Server 2008 (100)&quot;, even though its name is documented to be invalid at that compatibility level.

Heck, I can even do `CREATE DATABASE &quot; &quot;` (yes, that&#39;s a single space), which proves that the first character does *not* have to be a letter, underscore, at sign, or pound sign.

So I guess my question is, what characters **are** valid in an SQL Server database name? Are there any documented rules that are consistent with SQL Server&#39;s actual behavior?

What characters are valid in an SQL Server database name?

I&#39;m new to the concept `nvarchar(MAX)`. How many characters will it hold?


Content Type	Original Author	Original Content on Stackoverflow
Question	Sreedhar	View Question on Stackoverflow
Solution 1 - Sql Server	Raymund	View Answer on Stackoverflow

SQL Server - current user name

Sql Server Problem Overview

Sql Server Solutions

Solution 1 - Sql Server

Unique key with NULLs

How do I create a Dictionary that holds different types in C#

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