All supported database objects and functions reside in the srs schema namespace. For example, the distinguished name for the table scan_data would be referenced as srs.scan_data when using the namespace prefix.
Although use of the namespace prefix is not required in all cases, there are some cases where it is required, such as when referencing a user defined function in Microsoft SQL Server, or when another database object of the same name exists in the schema search path. For these reasons you should always reference the supported database objects and functions with the srs prefix.