How to avoid table crash?
I would say to try to use a different storage engine like InnoDB.

It sounds like you were using MyISAM which isn't crash safe. If you want to continue using MyISAM and it crashes in the future, you can fix it with an external program called myisamchk.

http://dev.mysql.com/doc/refman/5.0/en/myisamchk.html

 myisamchk --force --key_buffer_size=512M --sort_buffer_size=64M --read_buffer_size=8M --write_buffer_size=8M  /path/to/datadir/*/*.MYI