The process of maintaining views up to date is called _____.

Consider a relation R(A, B, C, D, E) with the following three functional dependencies,

1. AB -> C
2. BC -> D
3. C -> E

The number of superkeys in the relation R is

In relational database management systems (RDBMS), the efficient data structure used for internal storage representation is

Consider the following statements S₁ and S₂ about the relational data model :

S₁ : A relation scheme can have at most one foreign key

S₂ : A foreign key in a relation scheme R cannot be used to refer to tuples of R

Consider the following tables T1 and T2:

In table T1, P is the primary key, Q is the foreign key referencing R in table T2 with on-delete cascade and on-update cascade. In table T2, R is the primary key and S is the foreign key referencing P in the table T1 with on-delete set NULL and on-update cascade. In order to delete record (3,8) from table, numbers of additional record that need to be deleted from table T1 is 

A relational database contains two tables Student and Performance as shown below:

The primary key of the Student table is Roll_no. For the Performance table, the columns Roll_no. and Subject_code together from the primary key. Consider the SQL query given below:

SELECT S.Student_name, sum(P.Marks) FROM Student S, Performance P WHERE P.Marks > 84 GROUP BY S.Student_name;

The number of rows returned by the above SQL query is

Let the set of functional dependencies F = {QR → S, R → P, S → Q} hold on a relation schema X = (PQRS). X is not in BCNF. Suppose X is decomposed into two schemas and Z where Y = (PR) and Z = (QRS). Consider the two statements given below:

• I. Both Y and Z are in BCNF
• II. Decomposition of X into Y and Z is dependency preserving and a lossless.

Which of the above statements is/are correct?

Suppose a database system crashes again while recovering from a previous crash. Assume checkpointing is not done by the database either during the transactions or during recovery. Which of the following statements is/are correct?

Consider a database implemented using B+ tree for file indexing and installed on a disk drive with block size of 4 KB. The size of search key is 12 bytes and the size of tree/disk pointer is 8 bytes. Assume that the database has one million records. Also assume that no node of the B+ tree and no records are present initially in main memory. Consider that each record fits into one disk block. The minimum number of disk accesses required to retrieve any record in the database is

Consider the following two tables and four queries in SQL.

Book (isbn, bname), Stock (isbn, copies)

Query 1:

SELECT B.isbn, S.copies FROM Book B INNER JOIN Stock S ON B.isbn = S.isbn;

Query 2:

SELECT B.isbn, S.copies FROM B B LEFT OUTER JOIN Stock S ON B.isbn = S.isbn;

Query 3:

SELECT B.isbn, S.copies FROM Book B RIGHT OUTER JOIN Stock S ON B.isbn = S.isbn;

Query 4:

SELECT B.isbn, S.copies FROM B B FULL OUTER JOIN Stock S ON B.isbn = S.isbn;

Which one of the queries above is certain to have an output that is a superset of the outputs of the other three queries?