Cannot execute as the database principal because the principal "dbo" does not exist, this type of principal cannot be impersonated, or you do not have permission.

Set the database owner to fix this issue.

Goto database properties -->Files-->Owner.

sqlserver developer reference

http://technet.microsoft.com/en-us/library/dd206988.aspx

SQL Server: How to list all the indexes for a table

Use the in-build stored procedure 'sp_helpindex' to list all the indexes on a table.
Syntax: 'EXEC sp_helpindex 'table_name' on any sql editor.

SQL Server Profiler: How to get deadlock graph

How to save a deadlock graph by using SQL Server Profiler. Deadlock graphs are saved as XML files.

To save deadlock graph events separately

1. Goto the File menu, click New Trace, and then connect to an instance of SQL Server.
   The Trace Properties dialog box appears.

   Note:
   If Start tracing immediately after making connection is selected, the Trace Properties dialog box fails to appear, and the trace begins instead. To turn off this setting, on the Tools menu, click Options, and clear the Start tracing immediately after making connection check box.

2. In the Trace Properties dialog box, type a name for the trace in the Trace name box.
3. In the Use the template list, select a trace template on which to base the trace, or select Blank if you do not want to use a template.
4. Do one of the following:
   • Select the Save to file check box to capture the trace to a file. Specify a value for Set maximum file size.
     
     Optionally, select Enable file rollover and Server processes trace data.
     
     
   • Select the Save to table check box to capture the trace to a database table.
     
     Optionally, click Set maximum rows, and specify a value.
     
5. Optionally, select the Enable trace stop time check box, and specify a stop date and time.
6. Click the Events Selection tab.
7. In the Events data column, expand the Locks event category, and then select the Deadlock graph check box. If the Locks event category is not available, check Show all events to display it.
   The Events Extraction Settings tab is added to the Trace Properties dialog box.
8. On the Events Extraction Settings tab, click Save Deadlock XML Events Separately.
9. In the Save As dialog box, enter the name of the file in which to store the deadlock graph events.
10. Click All Deadlock XML batches in a single file to save all deadlock graph events in a single XML file, or click Each Deadlock XML batch in a distinct file to create a new XML file for each deadlock graph.

After you have saved the deadlock file, you can open the file in SQL Server Management Studio. For more information, see How to: Open, View, and Print a Deadlock File (SQL Server Management Studio).

How to shrink MSS database to save memory.

Logon to sqlserverManagementStudio

-->Right click on the database

-->Goto Tasks

-->Select Shrink

-->Click Ok.

Stored Procedure to fetch all orders created today

CREATE PROCEDURE todays_orders

AS

BEGIN

SELECT * FROM order_table where  order_date = DATEADD(DAY,-1,GETDATE())

END

How to reduce amount of network data for SQL server stored procedure?

SET NOCOUNT ON

Every time a SQL Statement is executed it returns the number of rows that were affected.  By using

"SET NOCOUNT ON" within your stored procedure you can reduce some traffic.  You can still use

@@ROWCOUNT variable to get number of rows.