Podcast
Questions and Answers
What is a significant advantage of using a DBMS regarding data loss?
What is a significant advantage of using a DBMS regarding data loss?
- DBMS eliminates the need for data storage.
- DBMS allows for automatic backup and recovery. (correct)
- DBMS provides unlimited storage capacity.
- DBMS requires manual backups periodically.
How does a DBMS facilitate the development of new applications?
How does a DBMS facilitate the development of new applications?
- By requiring extensive restructuring of existing data.
- By allowing instant access to existing data without re-creation. (correct)
- By mandating the use of specific programming languages.
- By limiting data access for new applications.
What does tunability in a DBMS refer to?
What does tunability in a DBMS refer to?
- The restrictions on data entry formats.
- The ability to automatically back up data.
- The process of adjusting the database to enhance performance. (correct)
- The capacity of the database to hold a large volume of data.
Which statement is true regarding the maintenance of DBMS?
Which statement is true regarding the maintenance of DBMS?
What is one benefit of central control in a DBMS?
What is one benefit of central control in a DBMS?
What is a drawback of traditional file processing systems compared to DBMS?
What is a drawback of traditional file processing systems compared to DBMS?
Which function is NOT efficiently handled by a DBMS?
Which function is NOT efficiently handled by a DBMS?
In what manner does a DBMS improve the performance of applications?
In what manner does a DBMS improve the performance of applications?
What distinguishes a solid-state drive (SSD) from a hard disk drive (HDD)?
What distinguishes a solid-state drive (SSD) from a hard disk drive (HDD)?
What does file organization refer to?
What does file organization refer to?
Which of the following best defines a file?
Which of the following best defines a file?
What is a key characteristic of nonvolatile flash memory?
What is a key characteristic of nonvolatile flash memory?
Which statement about file organization is true?
Which statement about file organization is true?
What role does file organization play in data retrieval?
What role does file organization play in data retrieval?
In what context is file organization described?
In what context is file organization described?
How can data be categorized within files?
How can data be categorized within files?
What is the primary purpose of the conceptual schema in database design?
What is the primary purpose of the conceptual schema in database design?
Which of the following is NOT a step in the logical database design process?
Which of the following is NOT a step in the logical database design process?
What does a physical schema describe?
What does a physical schema describe?
Which programming languages may be used during the database implementation phase?
Which programming languages may be used during the database implementation phase?
What is a key aspect of physical database design?
What is a key aspect of physical database design?
What stage follows the logical schema design in the database development process?
What stage follows the logical schema design in the database development process?
Which of the following constitutes a part of the database maintenance process?
Which of the following constitutes a part of the database maintenance process?
In which phase is the final database documentation typically completed?
In which phase is the final database documentation typically completed?
What is the primary purpose of data modeling in database design?
What is the primary purpose of data modeling in database design?
What is a significant challenge faced by database designers when developing a database?
What is a significant challenge faced by database designers when developing a database?
Which of the following best describes a data model?
Which of the following best describes a data model?
To avoid failures in database designs, what must database designers achieve?
To avoid failures in database designs, what must database designers achieve?
How does data modeling contribute to communication among stakeholders?
How does data modeling contribute to communication among stakeholders?
Why is it important to trace the evolution of data models?
Why is it important to trace the evolution of data models?
Which aspect of data is represented in a data model?
Which aspect of data is represented in a data model?
What is a common effect of misaligned data perspectives within an organization?
What is a common effect of misaligned data perspectives within an organization?
Which type of attribute allows for multiple values to be stored in a single attribute?
Which type of attribute allows for multiple values to be stored in a single attribute?
What is a derived attribute?
What is a derived attribute?
What purpose do database keys serve?
What purpose do database keys serve?
Which statement accurately describes a secondary key?
Which statement accurately describes a secondary key?
How does a compound key differ from a composite key?
How does a compound key differ from a composite key?
What is a constraint in the context of databases?
What is a constraint in the context of databases?
What happens if a data action violates a set constraint?
What happens if a data action violates a set constraint?
Which of the following best defines a composite attribute?
Which of the following best defines a composite attribute?
How can a derived attribute such as an employee's age be calculated?
How can a derived attribute such as an employee's age be calculated?
Which notation uses a dashed line to represent a derived attribute?
Which notation uses a dashed line to represent a derived attribute?
What does connectivity in an ERD describe?
What does connectivity in an ERD describe?
Which concept describes the maximum number of entities of one set associated with entities of another set?
Which concept describes the maximum number of entities of one set associated with entities of another set?
Which SQL command can be used to calculate a derived attribute in Microsoft SQL Server?
Which SQL command can be used to calculate a derived attribute in Microsoft SQL Server?
In which kind of relationship does cardinality ratios primarily apply?
In which kind of relationship does cardinality ratios primarily apply?
Which of the following statements is not true regarding derived attributes?
Which of the following statements is not true regarding derived attributes?
Which term refers to the number of entities associated with a relationship?
Which term refers to the number of entities associated with a relationship?
Flashcards
DBMS Backup and Recovery
DBMS Backup and Recovery
DBMS automatically backs up and recovers data, preventing data loss and saving time and resources compared to traditional file processing.
DBMS Application Development
DBMS Application Development
DBMSs make developing new applications easier because existing data is used, reducing development time.
DBMS Tunability
DBMS Tunability
DBMSs allow adjusting database settings (tuning) to improve performance, managed by Database Administrators (DBAs).
DBMS Maintenance Cost
DBMS Maintenance Cost
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DBMS Standards Enforcement
DBMS Standards Enforcement
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Data Loss Problem
Data Loss Problem
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Traditional File Processing
Traditional File Processing
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Database Administrators (DBAs)
Database Administrators (DBAs)
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Physical Storage Media
Physical Storage Media
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Solid State Drive (SSD)
Solid State Drive (SSD)
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File Organization
File Organization
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File
File
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File Access
File Access
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File Systems
File Systems
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File Structures
File Structures
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Hard Disk Drive (HDD)
Hard Disk Drive (HDD)
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Conceptual Schema
Conceptual Schema
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Logical Schema
Logical Schema
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Physical Schema
Physical Schema
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Database Implementation
Database Implementation
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Database Maintenance
Database Maintenance
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Logical Database Design Stages
Logical Database Design Stages
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Physical Database Design
Physical Database Design
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Atomic Elements
Atomic Elements
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Data Modeling
Data Modeling
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Data Model Purpose
Data Model Purpose
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Data Model Elements
Data Model Elements
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Data Model Importance
Data Model Importance
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Data Model Evolution
Data Model Evolution
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Data Model Benefits
Data Model Benefits
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Data Model Communication
Data Model Communication
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Data Model Abstraction
Data Model Abstraction
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Multivalued Attribute
Multivalued Attribute
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Derived Attribute
Derived Attribute
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Composite Attribute
Composite Attribute
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Database Key
Database Key
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Secondary Key
Secondary Key
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Composite Key
Composite Key
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Compound Key
Compound Key
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Constraints
Constraints
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Example of Derived Attribute
Example of Derived Attribute
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Chen Notation for Derived Attribute
Chen Notation for Derived Attribute
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Degree of Relationship
Degree of Relationship
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Connectivity
Connectivity
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Cardinality
Cardinality
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Mapping Cardinality
Mapping Cardinality
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Cardinality Ratio
Cardinality Ratio
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Study Notes
INFS 329: Database Management
- Course covers database management topics, including an overview, benefits, and challenges.
- Overview focuses on database concepts, terminologies, applications, and limitations.
- Students will be able to understand database concepts and the historical development of database systems.
- Students will be able to discuss the benefits and challenges of database management systems for organizations and individuals.
Database Terminologies
- Data: Raw, unprocessed facts stored in a database.
- Metadata: Data about data, including field descriptions, file types, structure, and access rules.
- Information: Processed data that makes sense, presented as query results or reports.
- Null: A value representing missing or unknown data.
- Entity: A thing, person, place, or concept in a database.
- Attribute (Field): Characteristics of an entity.
- Record (Tuple): A set of attribute values for an entity.
- Key: An attribute or attribute combination that uniquely identifies a record.
- Primary Key: Uniquely identifies a record in a table.
- Foreign Key: A field in one table linked to a primary key in another table for relationships.
What is a Database?
- An organized collection of related data.
- A database represents an aspect of the real world, reflecting changes in that aspect.
- Designed for a specific purpose, used by someone.
- Examples include phonebooks, class registers, lists of registered students and items sold in a store.
Databases are Structured
- Data is categorized and structured into tables.
What is a File?
- A collection of records or documents about a single organization, person, or subject.
Query
- Querying a database means retrieving specific data.
- Example query: "Salesperson='Mary' AND Price>100"
- Database examples of items sold in a grocery shop can be cited.
More Terminologies
- Entity: The concept the table describes (e.g., customer, course).
- Attribute (Field): Items of information unique to an entity (e.g., Customer ID, name, address).
- Record (Tuple): A set of values for each characteristic of an entity (e.g., a row in a table).
- Key: Used to define a necessary item.
- Primary Key: Uniquely identifies a record.
- Foreign Key: A primary key from another table that specifies relationships.
- Relationship: Linking two or more tables; describes an association among entities.
Summary of some salient DB terminologies
- Column (attribute): Represents data characteristics (e.g., customer ID, name...).
- Row (tuple): A row in a table holds data for one entity.
- Primary key: A unique identifier for each record.
DB terminologies: Query
- SELECT * FROM customers;
What is a Database Management System (DBMS)?
- Software programs managing a database.
- Stored, retrieve, and otherwise manage databases for applications and users.
- Manages large amounts of data to optimise recording, updating, modifications, and securing data.
Database Management System Diagram
- The diagram shows the relationship between a DBMS, the database, and the users, and how data is stored and accessed.
Why Database (DB) & DBMS?
- Areas of database usage: Banking, airlines, universities, and credit card transactions; and sales.
- Functions of DBMS: data storage and retrieval, managing metadata, limiting data repetition, supporting simultaneous data access, providing transactions, backup, and security features, and enforcing business rules.
- Benefits: minimizing data redundancy, sharing data efficiently, enforcing data consistency and integrity, offering searching, security, privacy, and backup & recovery facilities.
- Drawbacks: complexity, size, performance, and costs of conversion.
Advantages of DBMS
- Minimize data redundancy: Data is stored only once, in a single database, in management systems, thus eliminating redundant data.
- Data consistency: Data remains consistent and is updated to all users immediately when modifying any database values.
- Data integrity: Data integrity means unification of so many files into a single file. In DBMSs data is stored in different tables that are linked to each other. Users can easily input data and associate it. DBMS allows maintaining data integrity to decrease data duplication and inconsistency.
- Search capability: Rapid data retrieval to meet user queries.
- Security: Data protection.
- Privacy: Extent of data access by users is determined by database administrators (DBA).
- Simplicity: Data can be viewed in a clear and simple manner.
- Backup and recovery: Automated backups and recovery of databases if there is a system failure during data processing.
- Development of new applications: Easy to develop new applications based on available data.
- Performance: Improved performance in some situations by accessing data more quickly.
- Maintenance cost: Lower maintenance cost.
- Standards: Enforcement of data standards facilitates data migrations and the interchange of data.
- Less chances of data loss. Data loss is limited due to security constraints imposed on the database.
Disadvantages of DBMS
- Complexity: The complexity of DBMS programs/software is due to the provision of its expected functionalities (this also requires more skilled professionals to maintain and implement).
- Size: The DBMS's extensive functionality and complexity leads to disk space and substantial memory requirements to run efficiently.
- Performance: Some systems may now run slower than previously, but this can be addressed by adjusting the system and DBA expertise.
- Costs of Conversion: Costly to convert existing systems to run on a newer DBMS.
- Additional Hardware costs: The larger storage demands of a DBMS might require the addition of further hardware.
DBMS Terminology Summary
- Entity: A thing (object) about which data is stored.
- Attribute (Field): Description of an entity.
- Key: Unique value to identify a record.
- Primary Key: Identifies a row in a table.
- Foreign Key: A primary key linking one table to another, for relationship.
- Record (Tuple): A row in the table.
- Relations: Tables in a database.
Activity 2.1
- Discuss the challenges and benefits of database management software.
- Identify any three (3) drawbacks of DBMS, discuss how they can be mitigated.
Data Storage & File Structures
- Several types of data storage exist, categorised by speed, cost, and reliability.
- Secondary storage devices (e.g., magnetic tapes, hard disks, optical disks, solid-state drives) are used from storing data permanently, even when power is switched off, unlike main memory.
File Organisation
- File is a collection of data, usually stored on disk (a logical entity).
- File organization is the methodology used to store data.
- Heap file organization: Simplest, records ordered as they are inserted.
- Hash file organization: Records distributed randomly using a hash function to calculate addresses.
- Indexed sequential access method (ISAM): Sequential storage with extra indexes for quicker access.
- B+ tree organization: Efficient for large datasets with complex retrieval needs; internal nodes used for indexing and leaf nodes for data.
- Clustered tables organization: Tables stored together in a group where common columns share space.
File Access & File Structures
- Sequential access: Reading and writing data in the order it is stored.
- Direct access: Access to data records with specific record numbers.
- Stream access: Accessing data without specific record structures; sequential access to bytes addressed by a positive integer.
File systems
- A method to organize files on physical storage devices.
- Examples include Windows, macOS, Ubuntu, PlayStation, Xbox systems.
- Different file systems have different strengths and capabilities for handling data.
Database Development Process
- Enterprise data modeling (EDM): Creating an overall blueprint of organizational data.
- Systems Development Life Cycle (SDLC): An approach used to develop, maintain, and replace information systems with phases: Planning, Analysis, Design, Implementation, and Maintenance.
- Database Development Lifecycle (DBDLC): A life cycle specific for databases, with six phases: Database initial study, database design, implementation and loading, testing and evaluation, operation, and maintenance and evaluation.
- Prototyping: Creating a working model to gain user feedback and improve system design.
CASE Tools
- Computer-aided software engineering (CASE) Tools: Tools aiding in database design and application programming to enhance productivity.
- Enhance efficiency in designing databases; generate codes.
- Help in analysis, diagramming, and documentation of database models.
- Front-end CASE tools: focus on designing database models; back-end CASE tools help in generating database-related codes.
Data Models
- A representation of data objects, their characteristics, interactions, and types.
- Data models are important for database design and can be classified into various categories to satisfy different needs.
- Hierarchical, Network, Relational, Semantic, and Object-Oriented are the types.
Normalization
- The process of organizing data in a database to avoid redundant data and anomalies.
- Normalization works in a series of stages (normal forms; 1NF, 2NF, 3NF).
- 1NF ensures all columns are atomic (unbreakable into further parts).
- 2NF ensures no non-key attribute depends on only part of the primary key.
- 3NF removes transitive dependencies from non-key attributes.
Denormalization
- The process of adding redundancy to a database schema in order to improve performance (which might be slower when heavily normalized).
- Useful when frequent data retrieval queries are essential.
Deadlock
- A situation in a database where two or more processes are waiting indefinitely for each other to release a resource that they both need.
- Deadlocks can be detected via methods (like a timeout period) and resolved by either preempting or aborting a process.
Activity 8.1
- Explain what a deadlock is in the context of relational database management.
- Provide an example and explanation of a deadlock in a database.
- Explain Coffman's four conditions required to maintain a deadlock prevention strategy.
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Description
Test your knowledge on Database Management Systems (DBMS) and understand their advantages, functions, and performance improvements. This quiz covers key concepts including data loss prevention, application development, and file organization.