Question

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 the database schema and its state.

School Uniform Database
Attributes and Constraints				Table: COST
Table: UNIFORM				UCode	Size	COST Price
Attribute	UCode	UName	UColor	1	M	500
Constraints	Primary Key	Not Nul	-	1	L	580
Table: COST				1	XL	620
Attribute	UCode	Size	Price	2	M	810
Constraints	Composite Primary Key		>0	2	L	890
Table: UNIFORM				2	XL	940
UCode	UName	UColor		3	M	770
1	Shirt	White		3	L	830
2	Pant	Grey		3	XL	910
3	Skirt	Grey		4	S	150
4	Tie	Blue		4	L	170
5	Socks	Blue		5	S	180
6	Belt	Blue		5	L	210
				6	M	110
				6	L	140
				6	XL	160

Can they insert the following tuples to the COST Relation? Give reasons in support of your answer.

1. 7, S, 0
2. 9, XL, 100

Answer 1

1. No, it cannot be inserted as the price must be > 0.
2. Yes, it can be inserted.