Textual representation of database tables – Primary key attributes are underlined

Examples: – Book(Bno, Author, Title) – Loan(Bno, Rno, Loan date, Return date)

1. One-to-one (or zero-to-one)
   
2. One-to-may
   
3. Many-to-many (M-to-N). Often via a Bridge table. This table decomposes the M-to-N
   table in to one-to-many relationships.
   

Important to look at the primary key and the foreign key (= a primary key in another table).

1. Inner join (result = both circles)
   
2. Left outer join (you have customers with order and without order)
   

3. Right outer join (customers with orders, and orders without customers)

1. 
   

4. Full outer join (customers without orders, customers with order, orders without
customers)
5. Minus (customers without orders)