2. (50 points) [Research: ternary relationship] Consider the Trade relationship shown below. (This relationship was discussed in class.) Some ER schema design tools support only binary relationships, and in that case we should represent the ternary relationship using binary relationships instead. With this regard, read the textbook Section 3.9.1, including Figure 3.17, and do the exercises a and b below. M N Buyer Trade Seller K Broker (a) Draw an ER schema diagram with three binary relationships in the same manner as in Figure 3.17b, and explain why the three binary relationships together (i.e., in conjunction) are not equivalent to the ternary relationship Trade. (b) Draw an ER schema diagram with three binary relationships in the same manner as in Figure 3.17c, and explain why the three binary relationships together (i.e., in conjunction) are equivalent to the ternary relationship Trade. Sname Quantity Proj_name (a) SUPPLIER SUPPLY PROJECT Part_no PART Sname Proj_name (b) M N SUPPLIER SUPPLIES PROJECT M M CAN_SUPPLY USES Part_no N N PART (c) Sname Quantity Proj_name 1 N N 1 SUPPLIER SS SUPPLY SP) PROJECT N SP Part_no PART Figure 3.17 Ternary relationship types. (a) The SUPPLY relationship. (b) Three binary relationships not equivalent to SUPPLY. (C) SUPPLY represented as a weak entity type