Using SQL Server 2008, I'd like to create a UDF that gives me the create date of an object. This is the code:

create function dbo.GetObjCreateDate(@objName sysname) returns datetime as
begin
    declare @result datetime
    select @result = create_date from sys.objects where name = @objname
    return @result
end
go

I'd like to p开发者_开发百科ut this UDF in the master database or some other shared database so that it is accessible from anywhere, except that if I do that then the sys.objects reference pulls from the master database instead of the database that I'm initiating my query from. I know you can do this as the information_schema views sit in master and just wrap calls to local instances of sys.objects, so I'm hoping there's a simple way to do that with my UDF as well.

Try this:

CREATE FUNCTION dbo.GetObjCreateDate(@objName sysname, @dbName sysname) 
RETURNS datetime AS
BEGIN
    DECLARE @createDate datetime;
    DECLARE @params nvarchar(50);
    DECLARE @sql nvarchar(500);

    SET @params = '@createDate datetime OUTPUT';

    SELECT @sql = 'SELECT @createDate = create_date FROM ' + @dbName + '.sys.objects WHERE name = ''' + @objname + '''';

    EXEC sp_executesql @sql, @params, @createDate = @createDate OUTPUT;         

     RETURN @createDate
END
;

Why not do this instead?

1. Create a stored procedure that creates a view in the master database containing all of the information in sys.objects from each database on the server.
2. Create a DDL Trigger that gets fired whenever a CREATE, ALTER or DROP statement is executed for a database. The trigger would then execute the stored procedure in step #1. This allows the view to be automatically updated.
3. (Optional) Create a user defined function that queries the view for the creation date of a given object.

Stored Procedure DDL:

USE [master];
GO

CREATE PROCEDURE dbo.BuildAllServerObjectsView
AS

SET NOCOUNT ON;

IF OBJECT_ID('master.dbo.AllServerObjects') IS NOT NULL
    EXEC master..sp_SQLExec 'DROP VIEW dbo.AllServerObjects;';

IF OBJECT_ID('tempdb..Databases') IS NOT NULL
    DROP TABLE #Databases;

DECLARE @CreateView varchar(8000);
SET @CreateView = 'CREATE VIEW dbo.AllServerObjects AS' + CHAR(13)+CHAR(10) + CHAR(13)+CHAR(10);

SELECT name COLLATE SQL_Latin1_General_CP1_CI_AS AS 'name'
  INTO #Databases
  FROM sys.databases
 ORDER BY name;

DECLARE @DatabaseName nvarchar(100);
WHILE (SELECT COUNT(*) FROM #Databases) > 0
BEGIN
    SET @DatabaseName = (SELECT TOP 1 name FROM #Databases ORDER BY name);
    SET @CreateView +='SELECT N'+QUOTENAME(@DatabaseName, '''')+' AS ''database_name''' + CHAR(13)+CHAR(10)
                    + '      ,name COLLATE SQL_Latin1_General_CP1_CI_AS AS ''object_name''' + CHAR(13)+CHAR(10)
                    + '      ,object_id' + CHAR(13)+CHAR(10)
                    + '      ,principal_id' + CHAR(13)+CHAR(10)
                    + '      ,schema_id' + CHAR(13)+CHAR(10)
                    + '      ,parent_object_id' + CHAR(13)+CHAR(10)
                    + '      ,type' + CHAR(13)+CHAR(10)
                    + '      ,type_desc' + CHAR(13)+CHAR(10)
                    + '      ,create_date' + CHAR(13)+CHAR(10)
                    + '      ,modify_date' + CHAR(13)+CHAR(10)
                    + '      ,is_ms_shipped' + CHAR(13)+CHAR(10)
                    + '      ,is_published' + CHAR(13)+CHAR(10)
                    + '      ,is_schema_published' + CHAR(13)+CHAR(10)
                    + '  FROM ' + QUOTENAME(@DatabaseName) + '.sys.objects';
    IF (SELECT COUNT(*) FROM #Databases) > 1
        SET @CreateView += CHAR(13)+CHAR(10) + CHAR(13)+CHAR(10) + ' UNION' + CHAR(13)+CHAR(10);
    ELSE
        SET @CreateView += ';';  

    DELETE #Databases
     WHERE name = @DatabaseName;
END;

--PRINT @CreateView --<== Uncomment this to see the DDL for the view.

EXEC master..sp_SQLExec @CreateView;

IF OBJECT_ID('tempdb..Databases') IS NOT NULL
    DROP TABLE #Databases;

GO

Function DDL:

USE [master];
GO

CREATE FUNCTION dbo.GetObjCreateDate(@DatabaseName sysname, @objName sysname) RETURNS DATETIME AS
BEGIN
    DECLARE @result datetime;

    SELECT @result = create_date
      FROM master.dbo.AllServerObjects
     WHERE [database_name] = @DatabaseName
       AND [object_name] = @objname;

    RETURN @result;
END
GO

Sample Usage:

SELECT master.dbo.GetObjCreateDate('MyDatabase', 'SomeObject') AS 'Created';
SELECT master.dbo.GetObjCreateDate(DB_NAME(), 'spt_monitor') AS 'Created';

Does it have to be a function? If you just want it accessible everywhere, a trick is to put your code in a varchar and sp_executesql it:

create procedure dbo.GetObjCreateDate(@objName sysname) 
as
    declare @sql nvarchar(max)
    select @sql = 'select create_date from sys.objects where name = ''' + @objname + ''''
    EXEC sp_executesql @sql 
go

There seems to be an undocumented stored procedure that allows you to create your own system objects: sp_ms_marksystemobject

You can read more on http://www.mssqltips.com/tip.asp?tip=1612

Have a look at How to Write Your Own System Functions. I believe that it may help you