Let R be a relation on A = {0, 2, 7, 8} and R = {(7, 2), (8, 8), (8,0), (2, 7), (2, 2), (7,0)}. Are the following statements true or false? 1. R is an equivalence relation ? ? ? ? ? ? v V V V V 2. R is reflexive 3. R is transitive 4. R is anti-symmetric 5. R is a partial order 6. R is symmetric

Q1: All the following statements about weak and strong entity sets are True, Except: Select one: a. The weak entity set depends on the existence of the strong entity set b. PK of the strong entity set is not explicitly stored with the weak entity set c. An entity set that does not have a primary key is referred to as a weak entity set d. In ER-Diagram, the identifying relationship of a weak entity in represented as a double diamond e. The PK of the weak entity set is only formed by the primary key of the strong entity set Below are two pictures, each with a second and third question

Let R be a relation on A = {0, 1, 6, 8} and R = {(0,0), (8, 6), (6, 6), (8, 8), (1, 1), (1,0), (0, 1)}. Are the following statements true or false? 1. R is symmetric ? ? ? ? ? ? V V 2. R is transitive 3. R is reflexive 4. R is an equivalence relation 5. R is anti-symmetric 6. R is a partial order

:Given the pair of statements: A →~Z and Z=[Av (A•~Z)] 20. Construct a complete (ordinary) truth table for relation between the above pair of statements 21. How are the statements A-Z and Z = [A V (A • ~Z)] related? Given the argument: ~Av (B = C) B⇒ ~A ~A B Therefore, A. ~C 22. Construct a complete (ordinary) truth table. 23. Test for validity

Select the following relations on Z that are reflexive. {(a, b) | ab >0} {(a, b) | a>b-1} {(a,b) a² > b} 2 {(a,b) | a² = b² (mod 7)}

Let R₁ and R₂ be the relations on X={a,b,c}, R₁={ (b,a), (c,b), (a,c) } R₂={ (a,c), (b,c)} R₁-¹= R₂ ° R₁=

a) Define a relation R on R (the set of all real numbers) as follows: For all x, y E R, xRy → x < y. Is R reflexive, symmetric and transitive?

p.609, icon at Example 2 # 2. Let A be the set of all points in the plane with the origin removed. That is, Define a relation on A by the rule: A = {(x, y)|x, y = R} - {(0,0)}. (a, b)R(c, d) ↔ (a, b) and (c, d) lie on the same line through the origin. (a) Prove that R is an equivalence relation. (b) Describe the equivalence classes arising from the equivalence relation R in part (a). (c) If A is replaced by the entire plane, is R an equivalence relation?

1) Consider the following relation instance of R1(A, B, C) contains the tuples {(a1,b1.c1). (a2,b1,c1), (a3,b3,c3), (a4,b3,c3), (a5,b5.c5). (a6,b6,c6)} and S1(B, C, D, E) contains the tuples ((b1.c1,d1,e1), (b1.c1.d2.e2),.(b1.c1,d3,e3), (b2.c2,d2.e2), (b3,c3,d4,e4).(b6.c7.d8,e9)) The following SQL query will result in how many tuples? Select From R1 r LEFT OUTER JOIN S1 s (ON r.B= s.B AND r.C=s.C): (The answer will simply be an integer, like 25). Answer: 2) Consider a relation schema R = (A, B, C, D, E, F, G} with the following set of functional dependencies: F = (BG A, CGA, A BC, BC A, BD E, EF, CF B) The decomposition of R into R1 = (A, B, C, G), R2 = {B, D, E), R3 = (B, C, F) and R4 = (E, F) is O In BCNF but Not in 3NF. In 3NF but Not in BCNF. In 3NF and in BCNF. Not in 3NF and Not in BCNF 3)

it says relation hotel already exist