Basic Terminology of Databases
Database:
A database is a structured collection of data that is organized and stored in a way that allows for efficient retrieval and manipulation. It acts as a central repository for storing and managing information.
Table:
A table is a fundamental component of a relational database. It represents a collection of related data organized in rows and columns. Each row in a table is called a record, and each column represents a field or attribute.
Record:
A record is a single entry or row in a database table. It contains specific information related to an entity, such as a customer, product, or employee.
Field/Attribute:
A field or attribute is a single piece of data within a record. It represents a characteristic or property of the entity being described. For example, a customer record might have fields such as name, email, and phone number.
Primary Key:
The primary key is a unique identifier for each record in a table. It ensures that each row has a distinct identity and allows for efficient retrieval and referencing of specific records.
Foreign Key:
A foreign key is a field in a table that establishes a link between two tables. It references the primary key of another table, creating a relationship between the two.
Index:
An index is a data structure that enhances the performance of database queries. It speeds up data retrieval by creating a reference to the locations of specific data values, reducing the need for full table scans.
Query:
A query is a request for specific data from a database. It allows users to extract information based on certain conditions or criteria.
Normalization:
Normalization is the process of organizing data in a database to minimize redundancy and improve data integrity. It involves breaking down tables into smaller, well-structured entities to eliminate data duplication.
Communication through the Internet
Internet:
The internet is a global network of interconnected computers and servers that communicate with each other using a set of standardized protocols.
IP Address:
An IP (Internet Protocol) address is a unique numerical label assigned to each device connected to a network. It serves as an identifier for locating and routing data packets across the internet.
Packet:
A packet is a unit of data that is transmitted over the internet. It contains both the data being sent and the necessary information for its delivery, such as source and destination IP addresses.
HTTP (Hypertext Transfer Protocol):
HTTP is the foundation of data communication on the World Wide Web. It enables web browsers to request and receive web pages and other resources from web servers.
URL (Uniform Resource Locator):
A URL is a web address that specifies the location of a resource on the internet. It consists of the protocol (e.g., HTTP or HTTPS), domain name, and optional path to the specific resource.
DNS (Domain Name System):
DNS is a system that translates human-readable domain names (e.g., http://www.example.com) into IP addresses, allowing users to access websites without needing to remember the numeric IP addresses.
HTTPS (Hypertext Transfer Protocol Secure):
HTTPS is a secure version of HTTP that uses encryption (SSL/TLS) to protect data transmitted between the web browser and the web server, ensuring secure communication.
SMTP (Simple Mail Transfer Protocol):
SMTP is the standard protocol used for sending and receiving email messages over the internet.
FTP (File Transfer Protocol):
FTP is a protocol used for transferring files between computers on the internet. It allows users to upload and download files from FTP servers.
TCP/IP (Transmission Control Protocol/Internet Protocol):
TCP/IP is the foundational protocol suite for internet communication, responsible for routing data packets and ensuring reliable transmission.
Router:
A router is a network device that forwards data packets between different networks, allowing devices on different networks to communicate with each other.
Firewall:
A firewall is a security system that monitors and controls incoming and outgoing network traffic, protecting networks and devices from unauthorized access and potential threats.
Modem:
A modem (modulator-demodulator) is a device that converts digital data from a computer into analog signals for transmission over communication channels like telephone lines, cable lines, or fiber optics, and vice versa.