SQL Server – How to Get Database Name in Stored Procedure

dynamic-sqlsql serversql-server-2008-r2stored-procedures

Weird question?…maybe, but I have a need. 🙂

I have a stored procedure that I want to use universally in any database.
The stored procedure generates some dynamic SQL and then executes that SQL in a database that is passed in as one of the parameters in this procedure.

BUT I want to make the database parameter optional and when no database name is passed in, I want the dynamic SQL to execute within the same database that the procedure itself was called from. (Please keep in mind this procedure could be executed across databases and not within the same database that the procedure itself lives in.)

Best Answer

You can easily tell the dynamic SQL execute in a specific database by dynamically building a [database].sys.sp_executesql command:

USE your_database;
GO

CREATE PROCEDURE dbo.DatabaseNameOptional
    @db sysname = NULL
AS
BEGIN
  SET NOCOUNT ON;

  DECLARE @sql nvarchar(max) = N'SELECT DB_NAME(); /* other stuff */'

  DECLARE @exec nvarchar(770) = COALESCE(@db, DB_NAME())
    + N'.sys.sp_executesql';

  -- alternatively, just leave DB_NAME() out of it:

  --DECLARE @exec nvarchar(770) = COALESCE(@db, N'')
  --  + N'sys.sp_executesql';

  EXEC @exec @sql;
END
GO

Try it out:

USE your_database;
GO

EXEC dbo.DatabaseNameOptional;
GO  -- output = your_database

EXEC dbo.DatabaseNameOptional @db = N'master';
GO  -- output = master

USE tempdb;
GO

EXEC your_database.dbo.DatabaseNameOptional;
GO  -- output = your_database

EXEC your_database.dbo.DatabaseNameOptional @db = N'master';
GO  -- output = master

In the execution context of the procedure, though, no, I don't think there's any way to determine where the call originated from (or to run in that context). That's the benefit of using a system-marked procedure in master - if that's the functionality you want, you need to decide if "putting objects in master" is ickier than "not getting what I want."

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