For java and android developers.
To avoid definite two fields of the same value, consider using @Unique or @Index at the first field.
@Unique : Any two fields mustn't equal the same value.
@Index : All fields must be auto increased as 0,1,2,3, ... .
to see how to easy to use.
This plugin is opened at Github, if you like it, plz give me a start, tks.