Domain integrity constraint

1. Describe the characteristics a table must have to be considered a relation.2. Define the term domain, and explain the significance of the domain integrity constraint to a relation.3. Using EARe notation to define its entity, give an original example of a table that is not a proper relation. Explain what makes it not a relation.4. Under what circumstances can a relation have duplicate rows?5. Define the term non-unique key and give an original example with non-unique keys, using EARe notation to define its entity.6. Give an original example of a relation with a unique composite key, using EARe notation to define its entity.7. What is a surrogate key, and under what circumstances would you use one?8. Explain the term foreign key and give an original example, using EARe notation to define its entity.