Question 1

Which of the following is a highly popular technique for creating a data model with which the developers describe the content of a database by defining what is to be stored in the database and the associations among them?

Accepted Answer

The entity-relationship (E-R) data model is a highly popular technique for creating a data model. It allows developers to describe the content of a database by defining what is to be stored in the database and the associations among them. It uses graphical symbols to represent entities, relationships, and attributes. UML is a general-purpose modeling language that can be used to model software systems, while an object-relational model is a hybrid data model that combines the features of both object-oriented and relational models. Data integrity model is a concept used to ensure the accuracy and consistency of data in a database. None of these alternatives are as appropriate as the E-R model for the purposes described.

Question 2

Which of the following is true of entities?

Accepted Answer

Entities' characteristics are described by attributes. An identifier's value is associated with every instance of an entity, but not necessarily every entity in the data model. Entities can represent both logical constructs and physical objects, so B is incorrect. Relationships between entities are not attributes, so D is incorrect.

Question 3

A data model does not depict the relationships among the data.

Accepted Answer

A data model does depict the relationships among the data. It defines how different data objects interact with each other and how they are related to each other. This is essential for understanding the overall structure and behavior of the data within a system or organization.

Question 4

The process of converting poorly structured tables into two or more well-structured tables is referred to as ________.

Accepted Answer

Normalization is the process of converting poorly structured tables into two or more well-structured tables by organizing data into tables and establishing relationships between the tables based on their keys. This helps to eliminate redundancy and inconsistencies in the database and ensures data integrity. Replication refers to creating and maintaining copies of the same database on multiple servers or locations. Integration refers to combining different data sources or systems into a single system or application. Actualization is not a commonly used term in the context of database design.

Question 5

A data model is a logical representation of the structure of the data.

Accepted Answer

A data model is indeed a logical representation of the structure of the data. It defines the relationships between different data entities and their attributes, as well as the rules and constraints that govern the data.

Question 6

Which of the following is true of an E-R diagram?

Accepted Answer

The answer of Which of the following is true of...

Question 7

Once the users have validated and approved the data model,it is transformed into a ________.

Accepted Answer

Once the data model has been validated and approved by the users, it can be transformed into a database design. A database design is a description of how the data will be stored, organized, and accessed in a database. It includes details such as the tables, fields, relationships, and constraints that make up the structure of the database. This database design serves as a blueprint for creating the actual database.

Question 8

________ are attributes whose values are associated with one and only one entity instance.

Accepted Answer

Identifiers are unique attributes that identify a specific entity instance. They cannot be duplicated or shared by multiple entities.

Question 9

The easiest time to change the database structure is ________.

Accepted Answer

During the data modeling stage, the database structure is still being designed and no actual database has been constructed yet. Therefore, it is easier to make changes to the structure during this stage than it is after constructing the database.

Question 10

In a university,each adviser can advise multiple students,but each student can have only one adviser: In a data model,this can be best represented by a(n)________.

Accepted Answer

This relationship describes that each adviser can have multiple students, but each student can have only one adviser. It is a one-to-many (1:N) relationship where the adviser is the one, and the student is the many.

Question 11

Which of the following is true of a data model?

Accepted Answer

A data model is a logical representation of the structure of data, which includes entities, attributes, and relationships among them. It is created before the database is designed as it provides the blueprint for the database. Option B refers to a single-valued attribute, and option D is incorrect as a data model describes the relationships among data.

Question 12

Maximum cardinality in an E-R diagram refers to the maximum number of ________.

Accepted Answer

The maximum cardinality in an E-R diagram refers to the maximum number of entities that can be involved in a relationship. It defines the upper bound of the number of entities that can participate in a relationship. For example, a relationship between a customer and an order may have a maximum cardinality of "many" on the order side, indicating that a customer can place multiple orders, but an order can only belong to one customer.

Question 13

Database practitioners classify tables into various ________ according to the kinds of problems they have.

Accepted Answer

Tables are classified into various normal forms (1NF, 2NF, 3NF, etc.) based on the dependencies that exist between their attributes. This helps in eliminating redundancies, anomalies, and inconsistencies in the data and ensures data integrity. Entities refer to objects or concepts in a domain that can be uniquely identified. Cardinalities describe the relationships between entities in terms of their participation and connectivities. Attributes refer to the properties or characteristics of an entity that can be described by values.

Question 14

The general goal of normalization is to ________.

Accepted Answer

The general goal of normalization is to reduce data redundancy and construct tables such that every table has a single topic, which improves data consistency and integrity. A single table should represent a single entity or concept in the database, making it easier to manage and query the data. Options A, B, and C are not correct because they do not accurately reflect the purpose of normalization.

Question 15

A(n)________ notation signifies that an adviser can be related to many students and that a student can be related to many advisers.

Accepted Answer

The N:M notation signifies a many-to-many relationship between entities, which fits the scenario where an adviser can advise many students and a student can have many advisers. Option A (1:N) would imply that each student is advised by only one adviser, which is not the case here. Option C (N:1) would imply that each adviser has only one student, which is also not true. Option D (N:N) is just another way of representing the many-to-many relationship using a diamond shape, but it does not offer any additional information beyond what is already represented by the N:M notation.

Question 16

The little lines in an E-R diagram used as shorthand to represent multiple relationships are referred to as a(n)________.

Accepted Answer

Crow's foot notation is used to represent multiple relationships between entities in an E-R diagram. It is called a crow's foot because it resembles the footprints of a crow. The other options are not related to representing multiple relationships in an E-R diagram.

Question 17

Normalized tables eliminate ________.

Accepted Answer

Normalization is the process of organizing data in a database to minimize data redundancy. Normalized tables eliminate data duplication, which is a common problem in unnormalized tables. Normalization helps to reduce the data storage space required, improve data consistency, and simplify database maintenance. Normalization does not eliminate data dependency, data entry, or data conversion.

Question 18

In an organization,a single clerk is working in the administrative department: The notation that accurately indicates this relationship is ________.

Accepted Answer

The notation 1:1 represents a one-to-one relationship, which means that one record in a table corresponds to exactly one record in another table. In this case, one clerk is working in the administrative department, and there is no indication of multiple clerks or multiple departments, so the 1:1 relationship accurately reflects this situation. The other options do not accurately describe the relationship between a single clerk and the administrative department.

Question 19

The data integrity problem can occur only if data are ________.

Accepted Answer

Data integrity problems often occur when data is duplicated, leading to inconsistencies and errors in the database.

Question 20

________ describe the characteristics of entities.

Accepted Answer

Attributes are the characteristics or properties that describe an entity in a database. For example, for a "customer" entity, attributes can be name, address, age, gender, etc. Dependencies describe the relationship between entities, cardinalities describe the number of entities that can be associated with another entity, and alternatives refer to different options or possibilities. However, only attributes specifically refer to the characteristics of entities.

Quiz 17: Database Design