My first HTML document

This is personal study note Copyright and original reference: https://www.youtube.com/watch?v=y6Rpp9yEMQI&list=PLuHgQVnccGMDF6rHsY9qMuJMd295Yk4sa ================================================================================ Edit ERD before:

after:

================================================================================ - Consider the relationship between 'Author' and 'Dormant' - Cardinality 'One author' can have 'one dormant' (1) 'One dormant' can have 'one author' (1) - Optionality 'One author' can have 'no dormant' (optional) 'One dormant' must have 'author' (mandatory) - Table scheme Author id text dormant_id 1 kim 1 2 park 2 3 lee Dormant id dormant author_id 1 kim 1 2 park 2 author () : dormant (1) author () : dormant (optional) author (1) : dormant (1) author (mandatory) : dormant (optional) ================================================================================ Create table for dormant

================================================================================ In 1:1 relationship, who should have FK? It's unclear

Author table is more super entity In other words, dormant should know author table But author table doesn't need to know dormant table dormant table is depending on author table Author table (parent table) : dormant table (child table) Author table (PK) : dormant table (FK) ================================================================================ Drag and drop from parent to child tables

================================================================================ Install foreign key of author into Dormant table

================================================================================ The installed foreign key into Dormant table

================================================================================ 1 0...1 means author (1) : dormant (1) author (mandatory) : dormant (optional)

================================================================================ author (1) : dormant (1) author (mandatory) : dormant (optional) author : dormant (foreign key of author is installed in dormant table)