17. The one-to-many (1:M) relationship is easily implemented in the relational model by putting the of the "1" side in the table of the "many" side as a a. primary key, primary key b. primary key, foreign key c. foreign key, primary key d. foreign key, foreign key 18. A(n) table is the implementation of a composite entity used to implement an M:N relationship. a. linking b. bridge c. associative d. association 19. A(n) is an orderly arrangement used to logically access rows in a table. a. primary rule b. superkey c. relationship d. index 20. Relation schema R={A1,A2,.,An} is a set of attributes S subset-of R with the property that no two tuples t1 and t2 in any legal relation state r of R will have t1[S]=t2[S] a. Normal form b. Super key c. Candidate key. d. Foreign key 21. In a university, the data of students such as student id, name, and address are recorded in the STUDENT table and the courses are stored in a COURSE table by the course code, number of credits, and professor teaching. Usually, a student takes up to 5 courses per cycle, and each course has a minimum of 2 students. What kind of relationship exists between the courses and students? a. 1:1 b. 1:M c. Functional dependence. d. M:N 22. A database stores the data of the sales using the primary key RECEIVE_NUM in the SALE table and the products in the PRODUCT table with primary key PROD_NUM. To create the relation that represents what products were sold in a SALE a M:N relationship is necessary. What should be used to represent this in a relational model? a. composite attribute with RECEIVE_NUM + PROD_NUM b. composite entity with RECEIVE_NUM + PROD_NUM c. a product table SALE x PRODUCT d. a join table SALE + PRODUCT