A relation can have several candidate keys. True False Question 2 (10 points) A relation has only one primary key, a candidate key designed as the pr True False Question 3 ( 10 points) A foreign key in a relation R1 is a candidate key in a relation R2. True False Question 4 ( 10 points) A check constraint is inter-relational. True False Question 5 (10 points) A foreign key constraint is intra-relational. True False Check all that apply. We consider the constraint: A class start tim end time. The constraint is ... Static Dynamic Structural/syntactic Semantic Question 7 (10 points) Check all that apply. We consider the constraint: In teaching assignr assigns professors to courses, each individual assignment should con exactly one professor and one course. The constraint is ... Semantic Structural/syntactic Static Dynamic Question 8 (10 points) MySQL SQL and PostgreSQL permit to define the same reactive and re constraints. True False