List of top Database Management Systems Questions

Consider the following relational schema along with all the functional dependencies that hold on them. 
R1(A, B, C, D, E): { \( D \rightarrow E \), \( EA \rightarrow B \), \( EB \rightarrow C \) } 
R2(A, B, C, D): { \( A \rightarrow D \), \( A \rightarrow B \), \( C \rightarrow A \) } 
Which of the following statement(s) is/are TRUE?

A tuple within a relation must be ______.
Which two constraints when applied together will produce a primary key constraint?
Which two constraints when applied together will produce a primary key constraint ?
(A) NOT NULL
(B) UNIQUE
(C) DEFAULT
(D) ZERO
Choose the correct answer from the options given below:
Which statement is used to add a constraint in existing attribute of a relation?
The Lucas sequence Ln is defined by the recurrence relation: Ln = Ln−1 + Ln−2, for n ≥ 3, with L1 = 1 and L2 = 3. Which one of the options given is TRUE?