SQL File and Filegroups

Clarifications

allow you to have a single database span a set of physical files.

You can have several files in one group, so you can say spread the the load across a set of disks.

Note if you had say three files in a group, create a table and specify that group,
SQL server would put the first record in file 1, the second in 2 and the third in 3 and then roll round again.

Another use is to set up a group and put certain 'classes' of tables in it.
For instance, if you had lookup / parameter tables than are only chnaged in say a software update, you can put them in one group an make it readonly.

You get the performance gain from no locking and if a developer accidentally tries to write to one, the application will error.

Lot's of things you can do with them, like put your indexes on one disk and the table in another...

HtHs