curd-repository.md

first We don't need global updates, and this is a dangerous operation

   long count();
   void deleteAll();
   Iterable<T> findAll();

deleteById is ok

void delete(T entity);
void deleteAll(Iterable<? extends T> entities);

add methods return update num

<S extends T> int saveAll(Iterable<S> entities,int batchSize);
<S extends T> int  update(S entity);
<S extends T> int  updateAllField(S entity);