This is personal study note Copyright and original reference: https://www.youtube.com/watch?v=hGVdzWstuqc&list=PLuHgQVnccGMDF6rHsY9qMuJMd295Yk4sa ================================================================================ create "write" table ================================================================================ create relationship author to write (1:N) topic to write (1:N) ================================================================================ ================================================================================ author : write (N) author : write (optional) write : author (1) write : author (mandatory) ================================================================================