DBMS

In the context of schema normalization in relational DBMS, consider a set $F$ of functional dependencies. The set of all functional dependencies implied by $F$ is called the closur...

A schedule of three database transactions T1, T2, and T3 is shown. Ri(A) and Wi(A) denote read and write of data item A by transaction Ti, i = 1,2,3. The transaction T1 aborts at t...

An audit of a banking transactions system has found that on an earlier occasion, two joint holders of account A attempted simultaneous transfers of Rs. 10000 each from account A to...

Consider two relations describing teams and players in a sports league: * teams (tid, tname): tid, tname are team-id and team-name, respectively * players(pid, pname, tid): pid, pn...

Consider a relational schema team (name, city, owner), with functional dependencies {name → city, name → owner}. The relation team is decomposed into two relations, t1(name, city)...

Once the DBMS informs the user that a transaction has been successfully completed, its effect should persist even if the system crashes before all its changes are reflected on disk...

In the context of owner and weak entity sets in the ER (Entity-Relationship) data model, which one of the following statements is TRUE?

Let S be the specification: "Instructors teach courses. Students register for courses. Courses are allocated classrooms. Instructors guide students." Which one of the following ER...

Which of the following file organizations is/are I/O efficient for the scan operation in DBMS?

Which of the following statements about the Two Phase Locking (2PL) protocol is/are TRUE?

The symbol → indicates functional dependency in the context of a relational database. Which of the following options is/are TRUE?

The relation schema, Person (pid, city), describes the city of residence for every person uniquely identified by pid. The following relational algebra operators are available: sele...

Consider the following read-write schedule S over three transactions T1, T2, and T3, where the subscripts in the schedule indicate transaction IDs: S: r₁(z); w₁(z); r₂(x); r₃(y); w...

Consider the following two relations, R(A, B) and S(A, C) : R A B 10 20 20 30 30 40 30 50 50 95 S A C 10 90 30 45 40 80 The total number of tuples obtained by evaluating the follow...

Once the DBMS informs the user that a transaction has been successfully completed, its effect should persist even if the system crashes before all its changes are reflected on disk...

In the context of owner and weak entity sets in the ER (Entity-Relationship) data model, which one of the following statements is TRUE?

Let r i (z) and w i (z) denote read and write operations respectively on a data item z by a transaction T i . Consider the following two schedules. S 1 : r 1 (x) r 1 (y) r 2 (x) r...

Which one of the following statements is NOT correct about the B + tree data structure used for creating an index of a relational database table?

In an Entity-Relationship $$(ER)$$ model, suppose $$R$$ is a many-to-one relationship from entity set $$E1$$ to entity set $$E2.$$ Assume that $$E1$$ and $$E2$$ participate totally...

Consider the following tables T1 and T2. In table T1, P is the primary key and Q is the foreign key referencing R in table T2 with on-delete cascade and on-update cascade. In table...

Two transactions T₁ and T₂ are given as T1:r1(X)w1(X)r1(Y)w1(Y) T2:r2(Y)w2(Y)r2(Z)w2(Z) where ri (V) denotes a read operation by transaction Tᵢ on a variable V and wᵢ(V) denotes a...

Given the following statements: S1: A foreign key declaration can always be replaced by an equivalent check assertion in SQL. S2: Given the table R(a,b,c) where a and b together fo...

Consider a B + - tree in which the maximum number of keys in a node is 5. What is the minimum number of keys in any non-root node?

A clustering index is defined on the fields which are of type

The following functional dependencies are given : $$\eqalign{ & AB \to CD,\,AF \to D,\,\,DE \to F, \cr & C \to G.\,\,\,\,\,\,\,\,\,\,F \to E.\,\,\,\,\,\,\,\,\,G \to A. \cr} $$ Whic...

Let $${E_1}$$ and $${E_2}$$ be two entities in an E-R diagram with simple single-valued attributes, $${E_1}$$ and $${E_2}$$ are two relationships between $${E_1}$$ and $${E_2}$$, W...

Which of the following relational calculus expressions is not safe?