Chapter 1: Introduction to Databases

Flashcards covering key concepts from Chapter 1: Introduction to Databases, including definitions, architecture, roles, and basic database concepts.

What is a database?

A collection of related data that represents some aspect of the real world and is stored for a specific purpose.

What does data mean in database terminology?

Known facts that can be recorded and have implicit meaning.

Is data singular or plural in standard English, and what is the singular form?

Data is plural; datum is the singular form.

What is a DBMS?

A computerized system that enables users to create and maintain a database, including defining, constructing, manipulating, and sharing data, with meta-data stored in a catalog or dictionary.

What is a database system?

The combination of the database and the DBMS software.

What are NOSQL or big data storage systems used for?

To manage nontraditional data (such as posts, tweets, images, videos) for social media applications and large-scale data; often used by Google, Amazon, Yahoo, and for cloud storage.

What is cloud storage in this context?

Web-based storage providing storage capabilities on the Web for managing various data types (documents, programs, images, videos, emails).

Give examples of traditional database applications.

Bank deposits/withdrawals, hotel/airline reservations, library catalogs, online purchases, and supermarket inventory updates.

In the UNIVERSITY database example, what are the five files?

STUDENT, COURSE, SECTION, GRADE_REPORT, PREREQUISITE.

What data items are stored in the STUDENT record?

Name, Student_number, Class, Major.

What data items are stored in the COURSE record?

Coursename, Coursenumber, Credit_hours, Department.

What data items are stored in the SECTION record?

Sectionidentifier, Coursenumber, Semester, Year, Instructor.

What data items are stored in the GRADE_REPORT in the UNIVERSITY example?

The grades that students receive in various sections; it links students to sections/courses and their grades.

What is the PREREQUISITE file used for?

Stores prerequisite relationships between courses (Coursenumber and Prerequisitenumber).

What is a query in a database?

A request to retrieve data or perform updates; examples include retrieving transcripts, listing prerequisites, etc.

What is a transaction?

An executing program that includes one or more database accesses and must execute as a unit (isolation and atomicity).

What is the self-describing nature of a database system?

The DBMS catalog stores metadata describing the structure and constraints of the database.

What is data abstraction in a DBMS?

Providing a conceptual representation of data that hides storage and implementation details, enabling program-data and program-operation independence.

What is a view in a database?

A subset or derived data from base tables, possibly not stored explicitly; supports multiple views for different users.

Who are the main actors on the scene in a database environment?

Database Administrators (DBA), Database Designers, End Users (casual, naive/parametric, sophisticated, standalone), System Analysts and Application Programmers.

Who are the workers behind the scene?

DBMS system designers/implementers, Tool developers, and Operators/maintenance personnel.

What is data normalization and why is it used?

Normalization stores each logical data item in one place to reduce redundancy and ensure consistency; denormalization may be used temporarily to improve query performance.

What is referential integrity?

A constraint ensuring that a record in one file relates to records in another (e.g., every Section must relate to a valid Course).

What is impedance mismatch in databases?

The mismatch between programming language data structures and DBMS data structures; addressed by object-oriented databases and ORDBMS.