What that command does is make a new filesystem in that block device, that block device represents the WHOLE disk (S)csi (D)rive (A) SATA disk are treated with scsi emulation.
In short, that command erases all logical structure of the disk (the previous filesystem and partition tables) and creates a new (empty) filesystem, so in order to get your files back you should use testdisk to read the Real data written on the disk to make a new logical structure to access those files. You should be extra careful not to write any further on that disk, the more you write on the disk, the more probably to write over the Real data.
You can get testdisk from here
Make sure to read the documentation first.