How do the relations (tables) in SQL differ from the relations defined formally in Chapter 3? Discuss the other differences in terminology. Why does SQL allow duplicate tuples in a table or in a query result?

ER Model	Relational Model
Entity type	Entity relation
1:1 or 1:N relationship type	Foreign key(or relationship type)
M:N relationship type	Relationship relation and two foreign keys
n-ary relationship type	Relationship relation and n foreign keys
Simple Attributes	Attribute
Composite attributes	Set of simple component attribute
Multivalued attributes	Relation and foreign keys
Value set	Domain
Key attributes	Primary(or secondary) key