i understand what is collation is.
my question about DATABASE_DEFAULT
is DATABASE_DEFAULT mean the current running database or the Model database ?
imagine that i created a new database then i changed it is collation after creation process if i called this line
ON GP_DOCNUMBR COLLATE DATABASE_DEFAULT = DocumentNumber COLLATE DATABASE_DEFAULT
what DATABASE_DEFAULT will be?
DATABASE_DEFAULT is the collation which you set when the sql server was installed. I always get the default collation of the server by checking the collation of tempdb.