1 (a) (i) Analyse the difference between two-tier and three-tier architectures of a database management system with neat sketch. (ii) Let El and E2 be two entities in an E/R diagram with simple single-valued attributes. R1 and R2 are two relationships between El and E2, where Ri is onel to-many and R2 is many-to-many. R1 and R2 do not have any attributes of their own. Calculate the minimum number of tables required to represent this situation in the relational model and explain