[MySQL] - File Type Extensions

.MYD (MyISAM DATA) = เก็บ Data
.MYI (MyISAM INDEX) = เก็บ Index
.FRM (MyISAM FORMAT) = เก็บ Format

Ref :
- http://dev.mysql.com/doc/internals/en/myisam-introduction.html
- http://dev.mysql.com/doc/internals/en/the-myi-file.html