Macro define_sql 

macro_rules! define_sql {
    (
        $enum_name:ident
        $(
            $( @$mtype:ident ( $($margs:tt)* ) )?
            $name:ident $( { $($field:ident : $ftype:ty $( [ $mode:ident ] )? ),* $(,)? } )? => $sql:expr
        ),* $(,)?
    ) => { ... };
}