Hi All
I am practicing low level design diagram as I was asked on Amazon once so would like the community feedback on Low Level diagram of library management system.
In my understanding the diagrams available on the internet ( I have attached a picture below and can't name the website here) doesn't take separation of concerns into account.
They are missing DAL Layer and Business Layer.

The first diagram is what I have come up with the and the second one is from alternative place.
First: The most important feedback I am looking for is which is the correct style of drawing LLD.
Second feedback : if we want to search for a book based on location and availability ( essentially if I have to join few tables to get a result ) which repository should handle this job bookRepository, bookItemRepository, bookingRepository. In my example I have given this responsibility to bookRepository.
Third : When to use Repository and when to use Dao. Are my repositories correct or I should have used DAO
Below is the functional requirement ( I don't think it will make a difference)
User: can search a book/ reserve a book/
Admin: can add/remove boook
First Solution : (image link : https://ibb.co/Qj3Ckh8)

Solution from alternative place (image link :https://ibb.co/99LLXYp)