Data Management Overview

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Questions and Answers

What characterizes data in a database context?

Data can only exist in digital format.

Data is always structured and fixed.

Data must be immediately processed for it to hold value.

Data can be recorded and has implicit meaning. (correct)

Which of the following is a disadvantage of file-based systems?

Increased data isolation and separation. (correct)

Simplified management of data formats.

Ability to automatically update records.

Easy access to multiple records.

How do file-based systems handle data duplication?

By consolidating data into a single file.

By ensuring each program has its own copy of the same data. (correct)

By allowing sharing of data between applications.

By automatically syncing data across systems.

What does the term 'data dependence' refer to in file-based systems?

Changes to data structure are difficult to implement. Signup and view all the answers

What is an integrity problem in the context of file-based systems?

Data may not meet certain constraints, compromising its integrity. Signup and view all the answers

What issue does the atomicity problem in file-based systems refer to?

Transactions must be fully completed or not executed at all. Signup and view all the answers

Which of the following describes a consequence of having data scattered across files?

Time wastage due to duplicated entries. Signup and view all the answers

Why is enforcing security constraints difficult in file-based systems?

All users have access to all data due to lack of control. Signup and view all the answers

What function of a DBMS involves specifying the data types, structures, and constraints of the data?

Defining a database Signup and view all the answers

Which aspect of a database allows multiple users and programs to access it simultaneously?

Sharing Signup and view all the answers

What term is used to describe the value stored in a database that must be updated only once to maintain consistency?

Data integrity Signup and view all the answers

What is the term for the software that enables users to create and maintain a database?

Database management system Signup and view all the answers

What is stored in a database dictionary or catalog?

Meta data Signup and view all the answers

Which of the following is NOT considered an advantage of using a database?

Data inconsistency Signup and view all the answers

What does the term 'miniworld' refer to in the context of databases?

An aspect of the real world represented in a database Signup and view all the answers

What is the main purpose of protecting a database?

To prevent unauthorized access and system failures Signup and view all the answers

When is it more desirable to use regular files instead of a database?

For simple, well-defined applications that are not expected to change Signup and view all the answers

Which role is primarily responsible for authorizing access to the database?

Database Administrator Signup and view all the answers

What is NOT a typical data record found in a university database?

Market Share Signup and view all the answers

Which of the following best describes the responsibilities of database designers?

Choosing appropriate structures for data representation and storage Signup and view all the answers

Who among the following is primarily responsible for generating reports from the database?

End User Signup and view all the answers

Which of the following best describes the relationship between systems analysts and application programmers?

Systems analysts interact with end users to determine their needs Signup and view all the answers

What is a key responsibility of a Database Administrator?

Acquiring necessary software and hardware resources Signup and view all the answers

In which scenario would a database be least beneficial?

In embedded systems with limited storage Signup and view all the answers

What is one advantage of using a database regarding data integrity?

Data integrity is achieved through applying constraints. Signup and view all the answers

Which type of database language requires the user to specify how to retrieve the required data?

Procedural language Signup and view all the answers

What is a common disadvantage of Database Management Systems (DBMS)?

They can be complex and require a lot of memory. Signup and view all the answers

Which statement accurately describes the role of Data Definition Language (DDL)?

It is used to manipulate the structure of the database. Signup and view all the answers

What is one reason databases support multiple views of data?

To provide different perspectives for various users. Signup and view all the answers

What impacts the performance of a database negatively?

Being accessed by multiple applications simultaneously. Signup and view all the answers

What is a benefit of improved backup and recovery services in databases?

They ensure data can be restored after loss. Signup and view all the answers

Which of these is NOT a reason databases might require additional hardware?

To store minimal data efficiently. Signup and view all the answers

Study Notes

Introduction

Data is important for organizations
Data is known facts that can be recorded
Examples of data: name, mobile number, grades, temperature
Data is everywhere: universities, supermarkets, banks, interactive voice response (IVR) systems
File-based systems were an early attempt to manage data.

File Based Systems

They are a collection of application programs that perform services for users.
Each program defines and manages its own data.
They were based on the manual filing system.
They are not suitable when needing to cross-reference or process information in files.

File Based Processing

Data is stored and processed in files.

Disadvantages of File Based Systems

Data separation and isolation: data scattered in separate files with different formats making access difficult.
Data duplication: different systems/programs have separate copies of the same data, wasting time, storage space, and leading to inconsistent data.
Data dependence: physical structure and storage of data files are defined in application code, making changes difficult.
Integrity problems: data values must satisfy certain constraints, like salary limits and unique IDs, which are difficult to enforce.
Atomicity problems: transactions must happen entirely or not at all, difficult to ensure in file-based systems.
Security problems: difficult to restrict data access to authorized users and track user actions.
Limited data sharing: only one user can access files at a time.
Disaster recovery: limited or nonexistent recovery in case of hardware or software failures.

Solution: Database

A database is a collection of related data, managed by a Database Management System (DBMS).
DBMS enables users to create, maintain, and share databases.
Database applications interact with the database.
A database represents a real-world aspect, called a miniworld.

DBMS Functions

Defining a database: specifying data types, structures, and constraints. This definition is called metadata.
Constructing a database: storing data on a storage medium controlled by DBMS.
Manipulating a database: functions like querying for data retrieval and updating data.
Sharing a database: allowing multiple users and programs to access the database concurrently.
Protecting a database: security measures to prevent unauthorized access and protect against hardware/software failures.

Database Advantages

Control of data redundancy: integrates files to avoid multiple copies of the same data.
Data consistency: updates are reflected immediately for all users.
Sharing of data: multiple users can access data concurrently.
Improved data integrity: constraints ensure data integrity.
Support multiple view of the data: users can see different perspectives of the database through views.
Improved security: enforces security measures to prevent unauthorized access.
Program data independence: applications are less dependent on physical storage details.
More information from the same amount of data.
Improved backup and recovery services.

Database Languages

Procedural: users specify how to get data.
Declarative (nonprocedural): users specify what data they want without specifying how to retrieve it.
Data Definition Language (DDL): defines database structures, tables, attributes, data types, and constraints.
Data Manipulation Language (DML): manipulates data in the database, like inserting, updating, deleting, and retrieving.
Query: a statement to retrieve data.

Database Environment

Different users interact with the database, like students, teachers, or systems.
Different DBMS are available, including:
- Oracle
- MySql
- Access

Database Disadvantages

Complexity: complex software that requires expertise.
Size: large software, demanding more disk space and memory.
Cost: considerable cost varies based on functionality.
Additional hardware cost: may need larger machines and storage.
Performance: databases can impact application performance due to managing large data stores and multiple users.

When Not to Use DB

Simple database applications that are not expected to change.
Embedded systems with limited storage capacity.
No multiple-user access to data.

An Example

University Database: information about students, courses, and grades.
Data Records: Student, Course, Section, Grade Report, Prerequisite.

Database Catalog

Stores metadata about the database, like data types, structures, and constraints.

Database Users

Database Administrator (DBA): responsible for access control, coordination, monitoring, and acquiring resources.
Database Designers: identify data to be stored and choose appropriate structures.
End Users: interact with the database for querying, updating, and generating reports.
Systems Analysts and Application Programmers: analyze end user requirements and develop programs that interact with the database.

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Description

This quiz covers the importance of data within organizations, focusing on file-based systems for managing and processing data. It highlights the advantages and disadvantages of these systems, providing insights into issues like data duplication and isolation.