declare @MyDay varchar(20)
declare @query varchar(1000)
declare @DatabaseName varchar(128)
declare @snapshotName varchar(128)
declare @snapDataName varchar(128)
declare @snapFileName varchar(128)
declare @snapFilePath varchar(128)
set @Myday = (Select datename(weekday,getdate()))
print 'It is ' + @MyDay
Set @DatabaseName ='MyDB'
Set @SnapDataName='MyDB_Data'
Set @SnapshotName ='MyDB_Snapshot'+'_'+@MyDay
Set @SnapFilename ='c:\data\MyDB_Data'+'_'+@MyDay+'.ss'
Print 'Snapshot name is ' +@SnapshotName 

select * from sys.databases where source_database_id =db_id(@databasename) and name = @SnapshotName  
if @@rowcount <>0
begin
set @query = 'Drop database '+ @SnapshotName 
print @query
exec(@query)
end

set @query ='Create database '+ @SnapshotName + ' on  (Name = '''+@snapDataName +', FileName="'
+@SnapFilename +'") AS SNAPSHOT of '+ @databasename+';'
print @query
exec(@query)