CompSci 1.3: Exchanging Data

Vocabulary flashcards covering key concepts from the lecture on data exchange, databases, networks, and web technologies.

Asymmetric Encryption

An encryption technique where a public key is used to encrypt data, and a paired private key is used to decrypt it.

Dictionary Coding

A type of lossless compression where text entries are substituted by unique codes based on a dictionary.

Hashing

A one-way transformation of data into a hash value, used to validate credentials without revealing original data.

Lossless Compression

A compression algorithm that retains all data in the file, allowing for the original to be reconstructed without loss.

Lossy Compression

A compression algorithm that removes non-essential data, leading to unrecoverable data loss.

Run-Length Encoding

A type of lossless compression that stores repeated data occurrences as single values with their counts.

Symmetric Encryption

An encryption technique that uses the same key for both encryption and decryption.

Atomicity

In databases, all transactions should either completely succeed or completely fail.

Consistency

Each transaction must adhere to defined validation rules to maintain data integrity.

Durability

Once initiated, a database transaction must be completed under all circumstances.

Entity-Relationship Modelling

A visual method for describing data tables and relationships to reduce redundancy.

First Normal Form (1NF)

A database table with no repeating attributes, ensuring each record and attribute produce exactly one value.

Flat File Database

A database that uses a single table to store all data.

Foreign Key

An attribute that links two tables in a relational database, serving as a primary key in one and foreign key in another.

Indexing

The process of creating an index of primary keys for quick record retrieval.

Isolation

Ensuring no transaction overwrites others occurring simultaneously, maintaining consistent results.

Normalisation

The formal process of designing data tables to reduce redundancy and repetition.

Primary Key

A unique identifier for each record in a database table.

Record Locking

A technique that prevents simultaneous access to database records during editing or updating.

Redundancy

Unnecessary repetition of a data field in multiple tables, but needed for recovery purposes.

Referential Integrity

Ensuring that any changes to data are reflected in all linked tables.

Relational Databases

Databases with separate tables for each entity, linked by foreign keys.

Secondary Key

An alternative index for accessing or sorting records, less accurate than the primary key.

Second Normal Form (2NF)

A table in 1NF with removed repeating data across records, placed in a new table.

Third Normal Form (3NF)

A table in 2NF where all non-primary key attributes depend only on the primary key.

Transaction Processing

Ensuring logical operations in a database conform to ACID rules (Atomicity, Consistency, Isolation, Durability).

Circuit Switching

A data transmission method creating a dedicated channel between two network nodes.

Client-Server Network

A network structure where clients connect to central servers for resource management.

Domain Name System (DNS)

A hierarchical system that maps domain names to IP addresses.

Encryption

The process of converting plaintext data into ciphertext to prevent unauthorized access.

Firewalls

Applications that monitor and control network traffic to prevent unauthorized access.

Local Area Networks (LANs)

Networks connecting devices in a single geographical area.

Packet Switching

A method of data transmission that divides data into packets for independent delivery.

Peer-to-Peer Network

A network where computers connect directly and share resources without a central server.

Protocol Layering

A method dividing network system functions into layers with specific protocols.

Proxies

Servers that intercept data packets to hide source addresses and control access.

Transmission Control Protocol / Internet Protocol (TCP/IP) Stack

A suite of protocols allowing networked computers to communicate across connected layers.

Wide Area Networks (WANs)

Networks connecting devices over large geographical areas, often via third parties.

Cascading Style Sheets (CSS)

A style language for defining the layout and design of webpages.

Client-Side Processing

Data processing performed by the client’s browser using local resources.

HyperText Markup Language (HTML)

A markup language for writing the content of webpages.

JavaScript

A programming language for creating interactive web page elements.

PageRank Algorithm

An algorithm used by Google to rank websites based on the number of links.

Search Engine Indexing

Collecting and storing website data to enable fast information retrieval.

Server-Side Processing

Data processing performed by the web server, with requests sent from the client.