philipxy questions

philipxy answers

• Definition of the fourth normal form in normalization
• What is the difference between theta join and inner join?
• join 2 tables with their FKs in a 3rd table but not each other
• Should this ER diagram use a ternary relationship instead
• Can I use the same foreign key constraint in two different tables?
• How to add reference to a non primary key column of a table in rails5
• PostgreSQL using constants in foreign key
• Is there a well-defined difference between "normalizing" and "canonicalizing" data?
• Find date range overlaps within the same table, for specific user MySQL
• Relational algebra to count rows