GATE CS ER-model questions

Consider a relational database schema with a relation $R(A, B, C, D)$. If $\{A, B\}$ and $\{A, C\}$ are the only two candidate keys of the relation $R$, then the number of superkeys of relation $R$ is $\_\_\_\_$. (answer in integer)

In the context of DBMS, consider the two sets $\mathbf{T}$ and $\mathbf{S}$ given below. …

Let $\mathrm{S}$ be the specification: "Instructors teach courses. Students register for courses. Courses are allocated classrooms. Instructors guide students." Which one of the following $\mathrm{ER}$ diagrams CORRECTLY represents $\mathrm{S}$?

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

Which one of the following is used to represent the supporting many-one relationships of a weak entity set in an entity-relationship diagram?

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 in $R$ and that the cardinality of E1 is greater than the cardinality of E2. Which one of the following is true about $R$?

An ER model of a database consists of entity types $A$ and $B$. These are connected by a relationship $R$ which does not have its own attribute. Under which one of the following conditions, can the relational table for R be merged with that of A?

Consider an Entity-Relationship $(\text{ER})$ model in which entity sets $E_{1}$ and $E_{2}$ are connected by an $m:n$ relationship $R_{12}$. $E_{1}$ and $E_{3}$ are connected by a $1 : n$ ($1$ on the side of $E_{1}$ and $n$ on the side of $E_{3}$) relationship $R_{13}$. $E_{1}$ has two-singled attributes $a_{11}$ and $a_{12}$ …

Given the basic ER and relational models, which of the following is INCORRECT?

Consider the following $\text{ER}$ diagram The minimum number of tables needed to represent $M$, $N$, $P$, $R1$, $R2$ is Which of the following is a correct attribute set for one of the tables for the minimum number of tables needed to represent $M$, $N$, $P$, $R1$, $R2$?

Consider the following $\text{ER}$ diagram The minimum number of tables needed to represent $M$, $N$, $P$, $R1$, $R2$ is

Let $E_1$ and $E_2$ be two entities in an $E/R$ diagram with simple-valued attributes. $R_1$ and $R_2$ are two relationships between $E_1$ and $E_2$, where $R_1$ is one-to-many and $R_2$ is many-to-many. $R_1$ and $R_2$ do not have any attributes of their own. What is the minimum number of tables required to represent this situation in …