sys.data_spaces

I've just discovered the use of sys.data_spaces.
This'll give you the data files' information in your database.

use test
go
select * from sys.data_spaces

output:

name	data_space_id	type	type_desc	is_default
PRIMARY	1	FG	ROWS_FILEGROUP	1
SQLIndex_2	2	FG	ROWS_FILEGROUP	0
SQLIndex_1	3	FG	ROWS_FILEGROUP	0
SQLData_1	4	FG	ROWS_FILEGROUP	0
SQLData_2	5	FG	ROWS_FILEGROUP	0
SQLData_3	6	FG	ROWS_FILEGROUP	0
SQLData_4	7	FG	ROWS_FILEGROUP	0