various security functions

--execute as login = 'sa';
--execute as user = 'guest';

SELECT @@version
     --current context / execute as
     , user "user" --same as user_name()
     , user_name() "user_name" 
     , current_user "current_user"  
     , session_user "session_user" 

     --current login unless execute as
     , system_user "system_user" 
     , suser_name() "suser_name"  

     --original context
     , ORIGINAL_LOGIN() "original_login" 

GO

Example checking for DML type of trigger

Most of the time it is better to have separate insert/update/delete triggers if you need to do different things based on the DML type.  If you did want to have common code then could call a stored procedure with the DML type as a parameter.

In the rare instances where it may be more practical to have one trigger to rule them all, here is an example of how to check for the type of DML activity of the transaction executing the trigger.


ALTER TRIGGER dbo.tr_test_iud
   ON  dbo.test
   AFTER INSERT,UPDATE,DELETE
AS 
   DECLARE @trgtype varchar(10)
BEGIN
   SET NOCOUNT ON;

   IF EXISTS (SELECT TOP 1 1 FROM inserted)
      IF EXISTS (SELECT TOP 1 1 FROM deleted) SET @trgtype = 'UPDATE'
      ELSE SET @trgtype = 'INSERT'
   ELSE SET @trgtype = 'DELETE'

   PRINT @trgtype
END
GO


Keep in mind also, it is best practice to always code for there being more than one record involved in the transaction resulting in multiple records in the insert/deleted tables.

Server not configured for DATA ACCESS

Error: Server 'SERVER_NAME' is not configured for DATA ACCESS.


Resolution:
exec sp_serveroption 'SERVER_NAME', 'data access', 'true'
go

SQL Configuration Manager Cannot connect to WMI provider

Cannot connect to WMI provider. You do not have permission or the server is unreachable. Note that you can only manage SQL Server 2005 and later servers with SQL Server Configuration Manager.
Invalid namespace [0x8004100e]

This problem occurs because the WMI provider is removed when you uninstall an instance of SQL Server. The 32-bit instance and the 64-bit instance of SQL Server share the same WMI configuration file. This file is located in the %programfiles(x86)% folder.


To work around this problem, open a command prompt, type the following command, and then press ENTER:

Note For this command to succeed, the Sqlmgmproviderxpsp2up.mof file must be present in the %programfiles(x86)%\Microsoft SQL Server\number\Shared folder.

mofcomp "%programfiles(x86)%\Microsoft SQL Server\number\Shared\sqlmgmproviderxpsp2up.mof"

The value of number depends on the version of SQL Server:nnn

Microsoft SQL Server 2016        130
Microsoft SQL Server 2014        120
Microsoft SQL Server 2012        110
Microsoft SQL Server 2008 R2   100
Microsoft SQL Server 2008        100
Microsoft SQL Server 2005        90


https://support.microsoft.com/en-us/kb/956013

super trim

CREATE FUNCTION dbo.trim( @val nvarchar(max) )
RETURNS nvarchar(max)
BEGIN
   DECLARE @tab nchar(1)
         , @lf nchar(1)
         , @cr nchar(1)
         , @crlf nchar(2)

   SET @tab = char(9)
   SET @lf = char(10)
   SET @cr = char(13)
   SET @crlf = char(13) + char(10)

   RETURN ( replace(replace(replace(replace(ltrim(rtrim(@val)), @tab, ''), @crlf, ''), @lf, ''), @cr, '' ) )

END  --trim()

AFTER clause

ALTER DATABASE database-name SET OFFLINE WITH ROLLBACK AFTER 120 SECONDS

a call to LogonUserW failed

xp_cmdshell raises error "a call to LogonUserW failed with error code 1385"

An error occurred during the execution of xp_cmdshell. A call to 'LogonUserW' failed with error code: '1385'.

In order to fix this you need to open the Local Security Settings on the host machine.
 
Navigate to Security Settings -> Local Policies -> User Rights Assignment.
 
Open "Log on as a batch job" and add the user assigned as the xp_cmdshell proxy account