CPT103 Introduction to Database

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Questions and Answers

Which of the following data models is NOT directly used by any databases?

Relational Data Model

Hierarchical Data Model

Entity-Relationship Model (correct)

Network Data Model

Who originally introduced the relational model in 1970?

E.F. Codd (correct)

Ted Codd

Peter Chen

Charles Bachman

Which data model specifically uses graph structures for semantic queries?

Document Model

Object-Oriented Model

Graph Model (correct)

Relational Model

What is a characteristic of the Document model in data storage?

Stores documents in forms like JSON or XML Signup and view all the answers

Which one of the following options is a key feature of a Database Management System (DBMS)?

Must be accessible from remote computers Signup and view all the answers

Which data structure is commonly arranged for ease and speed of search and retrieval?

Organized collection of data Signup and view all the answers

What is the primary focus of the hierarchical data model?

Representing data in a tree-like structure Signup and view all the answers

What does the object-oriented model present information as?

Objects Signup and view all the answers

What is one primary purpose of a database management system?

To manage and store data efficiently Signup and view all the answers

Which of the following is considered a type of data example?

A docx file storing a project status report Signup and view all the answers

Which characteristic should data possess to be meaningful?

It should be relevant to its designed scenario Signup and view all the answers

What percentage of the assessment is attributed to the closed-book exam in the module?

70% Signup and view all the answers

What is an important activity to do before assessments according to the module information?

Revise contents weekly Signup and view all the answers

What does a relation represent in the context of databases?

One class/type of objects Signup and view all the answers

Which of the following statements about tuples is correct?

Each tuple must contain unique attribute combinations. Signup and view all the answers

Which key uniquely identifies each tuple in a relation?

Primary key Signup and view all the answers

Given the examples, which combination uniquely identifies an office room?

Building number and room number Signup and view all the answers

What ensures the uniqueness of a staff member's identity in a database?

Their unique ID number Signup and view all the answers

What is true about super keys in database relations?

They do not guarantee uniqueness. Signup and view all the answers

Which of the following is NOT a type of relational key mentioned?

Attribute key Signup and view all the answers

Why are duplicate tuples disallowed in a relation?

To ensure data integrity Signup and view all the answers

What does a foreign key in a database ensure?

It ensures correct references across relations. Signup and view all the answers

Which of the following correctly describes the attributes of a foreign key?

It can be a single or multiple attributes. Signup and view all the answers

In the database example provided, which ticket belongs to the group with the largest table size?

B1 Signup and view all the answers

Which combination of attributes can uniquely identify an office?

Building Number, Room, Room Size Signup and view all the answers

What is the definition of a superkey?

A set of attributes that uniquely identifies a tuple and may contain extra attributes. Signup and view all the answers

What information is NOT typically included in a foreign key relationship?

The size of the data table. Signup and view all the answers

Which of the following statements about candidate keys is false?

A relation can have multiple primary keys. Signup and view all the answers

Which option correctly classifies a primary key?

The candidate key selected to uniquely identify tuples. Signup and view all the answers

In the context of the given office data, which room has a printer?

Room 502 in Building 11 Signup and view all the answers

What is the function of an alternate key?

To provide a method for identifying tuples that is not the primary key. Signup and view all the answers

If a relation has multiple candidate keys, how many of these can be primary keys?

Only one candidate key can be a primary key. Signup and view all the answers

Which key consists of more than one attribute?

Composite key Signup and view all the answers

Study Notes

Module Overview

Instructors: Jianjun Chen, Jun Qi, Yu Liu with designated office hours.
Textbook: "Database Systems: a practical approach to design, implementation, and management" by Thomas M. Connolly and Carolyn E. Begg.
Assessment: 15% from two online quizzes and 70% from a closed-book exam.

Importance of Collaboration

Engaging in discussions enhances understanding of concepts and terminology.
Regular notifications from instructors regarding updates and important announcements.

Understanding Data

Data examples include documents (docx) and spreadsheets (Excel) containing relevant information.
Meaningful data requires specific contexts and restrictions on access to authorized users.

Data Models

Defined as organized collections of data structured for efficient search and retrieval.
Key models include:
- Relational Data Model: Data is organized in tables.
- Hierarchical Data Model: Data organized in a tree-like structure.
- Network Data Model: Data organized as a graph.
- Entity-Relationship Model: Used for teaching, not implemented in databases.
- Graph Model: Utilizes nodes and edges for semantic queries.
- Document Model: Stores information in JSON/XML.
- Object-Oriented Model: Information presented as objects.

The Relational Model

Introduced by E.F. Codd in 1970.
Enforces uniqueness with no duplicate tuples.
Each relation represents a class/type of objects with tuples as instances.

Relation Keys

Super Key: Any attribute(s) that uniquely identifies a tuple.
Candidate Key: A minimal super key with no proper subset also being a super key.
Primary Key: Selected candidate key for unique identification.
Foreign Key: Attribute(s) in one relation that reference a candidate key in another relation.

Examples of Relations

Staff table attributes might include ID, Name, Salary, and Department.
Combination keys are needed where single attributes are not unique (e.g., Building Number + Room).

Identifying Key Attributes

Tuples in staff or office relations can have overlapping attributes (like Name or Room Size) but must have unique identifiers (like ID or a combination of Building Number and Room).
Composite keys allow identification using multiple attributes.

Questions for Understanding

Queries to test knowledge on which attribute combinations uniquely identify relations, particularly in office and teaching staff scenarios.

Assessment Preparation

Encourage weekly revision and not being solely reliant on slides before assessments.
Utilize lab sessions to clarify doubts and enhance understanding of practical applications.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Welcome to CPT103, where you will explore the fundamentals of databases. This module covers the relational model, relational keys, and provides an understanding of database structures. Get ready to dive into the intriguing world of data management!