Customers and Products ERD (Show Reference (code/decode) Entities)
Library And Books ERD (Show "Books at Libraries" - 2 keys, 1 additional attribute)
Non-Profit ERD (Note that Person can have multiple skills but only one Role)
Piano Tuner Keys only ERD (Note the number of relationships with Piano)
Piano Tuner ERD (Note "Other details" and code value examples (eg))