Chapter 5: Data

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Questions and Answers

What is the primary focus of this chapter?

Software

People and processes

Hardware

Data (correct)

What are the two components of information technology that have little value without data?

Software and processes

Hardware and software (correct)

Processes and hardware

Data and people

What happens to data to become information?

It is transformed (correct)

It is discarded

It is stored

It is deleted

What is the role of technology in information systems?

To transform data into information Signup and view all the answers

What is the result of new data being generated at unprecedented speeds?

New data is being generated faster than we can transform it Signup and view all the answers

What are the three components of information technology?

Hardware, software, and data Signup and view all the answers

What do you need to open a word processor, a music application, or a web browser?

Data Signup and view all the answers

What is data in the context of information systems?

Raw facts Signup and view all the answers

What is the main limitation of relational databases?

They are not scalable Signup and view all the answers

What is the purpose of defining data types in a database?

To determine what functions can be performed with the data Signup and view all the answers

What is the term for a collection of related records in a database?

File Signup and view all the answers

What is the purpose of a data hierarchy?

To organize data in a database Signup and view all the answers

What is the term for a single unit of digital information?

Byte Signup and view all the answers

What is the data type for storing non-numeric data that is brief, generally under 256 characters?

Text Signup and view all the answers

What is the data type for storing data that cannot be entered via keyboard, such as an image or a music file?

Object Signup and view all the answers

What is the term for a collection of related fields in a database?

Record Signup and view all the answers

What is the main advantage of using a NoSQL database?

It is more scalable Signup and view all the answers

What is the term for a unit of measurement to quantify computer data?

Bit Signup and view all the answers

What is the largest database software vendor in the world?

Oracle Signup and view all the answers

What is the logical structure of the data items and their relationships in a database?

Data model Signup and view all the answers

What type of database organizes data into inter-related tables?

Relational database Signup and view all the answers

What is the term used to describe a database that contains only one file/table, with no relationships?

Flat file database Signup and view all the answers

What is the main difference between a database and a spreadsheet?

A database can mix different types of data together Signup and view all the answers

What is the most used database model today?

Relational database model Signup and view all the answers

What is the concept of allowing for a parent/child relationship between data?

Hierarchical database model Signup and view all the answers

What is the term used to describe the concept of not allowing multiple people to manipulate a piece of data at a time?

Record-locking Signup and view all the answers

What is the term used to describe databases that can be spread over several servers or even across the world?

NoSQL database Signup and view all the answers

What is the term used to describe the process of connecting a spreadsheet to a specific table or query in a database?

Data connection Signup and view all the answers

What is the estimated amount of data that will be created globally by 2025?

463 exabytes of data per day Signup and view all the answers

What is the term used to describe large data sets that conventional data processing technologies do not have sufficient power to analyze?

Big Data Signup and view all the answers

What is the purpose of a database?

To store and analyze data for decision-making Signup and view all the answers

What is an example of a non-digital database?

A filing cabinet Signup and view all the answers

What is the software used to create, store, maintain, and access database files?

Database Management System Signup and view all the answers

What is the purpose of a Database Management System (DBMS)?

To provide an interface for the user to interact with the database Signup and view all the answers

What is an example of a Database Management System (DBMS)?

Microsoft Access Signup and view all the answers

What is the term used to describe 'data about data'?

Metadata Signup and view all the answers

What is the purpose of aggregating data in a database?

To support reporting and analysis Signup and view all the answers

What is the term used to describe the collection of related information in a database?

Organized collection Signup and view all the answers

What is the primary purpose of data modeling in database design?

To develop a high-level conceptual representation of the database structure Signup and view all the answers

What is the primary key of the STUDENT table?

Student ID Signup and view all the answers

What is the purpose of defining a data type for a field?

To allocate the proper amount of storage space Signup and view all the answers

What is an Entity Relationship Diagram (ERD)?

A diagram that shows the relationships among tables of data Signup and view all the answers

What is the purpose of a foreign key in a database?

To connect to a primary key in another table Signup and view all the answers

What is normalization in database design?

The process of designing a database to reduce data redundancy and ensure data integrity Signup and view all the answers

What is the purpose of a data dictionary in database design?

To define the fields and structure of the database Signup and view all the answers

What is the primary key in a relational database?

A unique identifier for each record in the table Signup and view all the answers

What is the advantage of using a GRADE table in the School Database design?

It prevents data redundancy and ensures data integrity Signup and view all the answers

Why is it not suitable to use a student's name as a primary key?

Because it is not unique Signup and view all the answers

What is a characteristic of a valuable resource?

Data that is not redundant, inconsistent, inaccurate, or fails to meet the characteristics of valuable information Signup and view all the answers

What is the advantage of using a database approach over a file-based system?

It prevents data redundancy and inconsistencies Signup and view all the answers

What is the purpose of defining constraints in data modeling?

To restrict data values to specific ranges Signup and view all the answers

What is the purpose of the primary key in a table?

To uniquely identify each record in a table Signup and view all the answers

What is the relationship between the STUDENT and COURSE tables in the school database?

Many-to-many Signup and view all the answers

What is the purpose of identifying entities in data modeling?

To capture the data contained in the database Signup and view all the answers

What is the result of using non-database tools to store and manipulate business data?

Data becomes redundant, inconsistent, inaccurate, and fails to meet the characteristics of valuable information Signup and view all the answers

What is the advantage of the School Database design?

It makes it easy to change the design without major modifications Signup and view all the answers

Why is a primary key important in a relational database?

To uniquely identify each record in the table Signup and view all the answers

Why is data a valuable resource?

Because it is used to make business decisions Signup and view all the answers

What is the primary issue with redundant data in a database?

It can cause inconsistencies in the data set. Signup and view all the answers

What is the benefit of using a database approach to control redundant data?

It ideally stores each data item in only one place. Signup and view all the answers

What is meant by data integrity in a database?

The consistency among the stored data. Signup and view all the answers

What is the benefit of data sharing in a database?

It allows for more information to be produced from a given amount of data. Signup and view all the answers

What is the primary function of a database management system (DBMS)?

To create and manage databases Signup and view all the answers

What is the purpose of security features in a database management system?

To restrict unauthorized access to the data. Signup and view all the answers

What is the purpose of the recovery subsystem in a database management system?

To restore the database to its previous state in case of a failure. Signup and view all the answers

What is the term for the process of designing a database to reduce redundancy and ensure integrity?

Data normalization Signup and view all the answers

What is the primary language used for creating and manipulating relational databases?

SQL Signup and view all the answers

What is the benefit of using the database approach?

All of the above Signup and view all the answers

What type of database is the most widely used?

Relational database Signup and view all the answers

What is the benefit of using a database approach to manage data?

It allows for data sharing, security, and recovery. Signup and view all the answers

What is the purpose of database manipulation?

To analyze and manipulate relational data. Signup and view all the answers

What is the purpose of using a primary key in a relational database?

To set unique identifiers for each table Signup and view all the answers

What is the benefit of using SQL to manipulate a database?

It is a popular language for database use. Signup and view all the answers

What is the language used to create queries in databases?

SQL Signup and view all the answers

What is the benefit of using QBE (Query-by-Example)?

Generates SQL for you Signup and view all the answers

What is the term for a record in a table?

Record Signup and view all the answers

What is the purpose of defining the data type of a field in a relational database?

To ensure data integrity Signup and view all the answers

What is the term for an organized collection of related data?

Database Signup and view all the answers

What is a database?

An organized collection of related information Signup and view all the answers

What is the purpose of a Data Dictionary?

To define the fields and structure of the database Signup and view all the answers

What is Data Integrity?

The consistency among the stored data Signup and view all the answers

What is a Relational Database?

A database that organizes data into one or more related tables Signup and view all the answers

What is the purpose of Normalization in a database?

To reduce data redundancy and ensure data integrity Signup and view all the answers

What is Metadata?

Data that describes other data Signup and view all the answers

What is a NoSQL Database?

A type of database that operates using means other than relational tables Signup and view all the answers

What is the purpose of a Schema?

To provide an overall description of the database Signup and view all the answers

What is an Entity Relationship Diagram (ERD)?

A graphical representation of the relationships among data items Signup and view all the answers

What is Data Hierarchy?

The structure and organization of data in a database Signup and view all the answers

Study Notes

Data and Databases

Data is everywhere, and it is being generated every second of every day.
It is estimated that 463 exabytes of data will be created each day globally by 2025.
Big data refers to large data sets that conventional data processing technologies do not have sufficient power to analyze.

Databases

A database is an organized collection of related information.
Databases are not always digital – a filing cabinet, for instance, might be considered a form of database.
A database management system (DBMS) is software for creating, storing, maintaining, and accessing database files.
Examples of DBMS include Microsoft Access, Filemaker Pro, Oracle, IBM (DB2), Sybase, Microsoft (SQL Server), and MySQL.

Database Models

Databases can be organized in different ways by using different models.
The relational data model organizes data into inter-related tables.
Relational databases are easy to understand and use, and are often contrasted with a flat file database.
Flat File Database includes one-dimensional table of data organized in rows and columns.
Relational Database includes multiple tables of data that are related by a common field.

Data Hierarchy

A data hierarchy is the structure and organization of data in a database.
A data hierarchy consists of:
- File: a collection of related records.
- Record: a collection of related fields.
- Field: holds a single fact or attribute.
- Byte: a unit of digital information.
- Bit: a unit of measurement to quantify computer data.
Data types include:
- Text
- Number
- Boolean
- Date/Time
- Currency
- Paragraph Text
- Object

Designing a Database

The first step in database design is data modeling.
Data modeling includes capturing the:
- Entities: the data contained in the database.
- Relationships: between data items.
- Constraints: on data.
A schema is developed to provide an overall description of the database.
A data dictionary is created to hold the metadata, defining the fields and structure of the database.
Normalization is an important concept in database design, which aims to:
1. Reduce data redundancy.
2. Ensure data integrity.### Why Databases?
Data is a valuable resource, but it can become redundant, inconsistent, and inaccurate if not managed properly.
Using non-database tools like spreadsheets can lead to unmanageable and error-prone data.
The database approach offers several benefits, including control of redundant data, data integrity, data sharing, security, and recovery.

Control of Redundant Data

Redundant data is data that is repeated in a database, causing inconsistencies and errors.
The database approach aims to store each data item in only one place, minimizing redundancy.
Example: a student's name and major are recorded in both the registered student roster and student grade roster, making it difficult to update information.

Data Integrity

Data integrity means consistency among the stored data.
Example: a student's grade is recorded in the student grade roster, but the student's name is not found in the registered student roster, violating data integrity.
Database management systems provide capabilities to define and enforce certain constraints to ensure data integrity.

The integration of the whole data in an organization leads to the ability to produce more information from a given amount of data.
Centralizing data in one database makes it easier to share and access information.

Security and Recovery

Database management systems allow for restricting unauthorized access through security features that control user accounts.
Users may have different views of the database, and users may not need to be aware of how and where the data they refer to is stored.
If the computer system fails, the recovery subsystem is responsible for restoring the database to its previous state.

Database Manipulation

Once a database is designed and loaded with data, Structured Query Language (SQL) is used to analyze and manipulate the data.
SQL is a programming language used to create and manipulate databases.
Examples of SQL queries include retrieving a student's major and counting the total number of students in a database.

Database Design

Designing a relational database involves determining how the data is organized into tables, setting primary keys, and creating relationships among the tables.
Normalization is the process of designing a database to reduce redundancy and ensure data integrity.
The database approach allows for the control of redundant data, data integrity, data sharing, and security and recovery.

Key Terms

Attribute: A record is one instance of a set of fields in a table.
Big Data: A broad term for data sets so large or complex that traditional data processing applications are inadequate.
Database: An organized collection of related information.
Data Dictionary: A collection of metadata that defines the fields and structure of the database.
Data Hierarchy: The structure and organization of data in a database.
Data Integrity: Consistency among the stored data.
Database Management Systems (DBMS): Programs that provide user-friendly interfaces to view and change a database, create queries, and develop reports.
Database Manipulation: The use of a programming language to modify data in a database to make it easier to view or for the purpose of decision making.
Data Model: The logical structure of the data items and their relationships.
Data Sharing: The integration of the whole data in an organization leads to the ability to produce more information from a given amount of data.
Data Types: The type of data stored in a field, such as text, number, or date.
Entities: The data contained in the database, such as students, courses, or grades.
Entity Relationship Diagram (ERD): A diagram that shows the relationships among the tables of data.
Flat File Database: A database that contains only one file/table, with no relationships.
Hierarchical Database Model: A database model that connects data together in a hierarchy, allowing for a parent/child relationship between data.
Metadata: Data that describes other data.
NoSQL Databases: A type of database that operates using means other than relational tables.
Query-by-Example (QBE): A graphical query tool that allows users to retrieve data through visualized commands.
Record (row): A record is one instance of a set of fields in a table.
Redundant Data: Data that is repeated in a database, causing inconsistencies and errors.
Relational Database: A database that organizes data into one or more related tables.
Relationships: The connections between data items, such as students getting grades in courses.
Scale: The ability of a database to grow and expand as the amount of data increases.
Schema: A detailed description of the database structure and organization.
Structured Query Language (SQL): A programming language used to create and manipulate databases.

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Description

Learn about databases, data hierarchy, and more in this chapter on data. Explore the concepts and importance of databases in data management.