School uniform is available at M/s Sheetal Private Limited. They have maintained SCHOOL_UNIFORM Database with two relations viz. UNIFORM and COST. The following figure shows database schema and its state.

(a) Can they insert the following tuples to the UNIFORM Relation? Give reasons in support of your answer.
(i) 7, Handkerchief, NULL
Ans: Yes, it can be inserted as UColor does not have Not Null constraint.
(ii) 4, Ribbon, Red
Ans: No, it cannot be inserted as UCode is Primary key and 4 is already existing and so we can insert duplicate record in it.
(iii) 8, NULL, White
Ans: No, it cannot be inserted as UName has Not Null constraint.
(b) Can they insert the following tuples to the COST Relation? Give reasons in support of your answer.
(i) 7, S, 0
Ans: No, it cannot be inserted as Price should always be greater than 0.
(ii) 9, XL, 100
Ans: No, it cannot be inserted as UCode is Foreign key references from Uniform relation and UNIFORM relation 9 UCode does not exist and so we cannot insert it in COST relation.