IB Computer - Databases

Database

An organized collection of structured information or data, typically stored electronically in a computer system.

Purpose of Databases

To store, retrieve, and manage data efficiently and securely.

Relational Database

Organizes data into tables consisting of rows and columns, using SQL for data manipulation.

DBMS (Database Management System)

Software that uses a standard method to store and organize data, providing an interface between users and the database.

NoSQL Database

Designed for unstructured or semi-structured data, with flexible schema and horizontal scalability.

SQL (Structured Query Language)

A language used for managing and manipulating relational databases.

Document Store

A type of NoSQL database that stores data in document formats like JSON or BSON (e.g., MongoDB, CouchDB).

Key-Value Store

A NoSQL database that stores data as a collection of key-value pairs (e.g., Redis, Amazon DynamoDB).

Column-Family Store

A NoSQL database that stores data in columns rather than rows (e.g., Apache Cassandra, HBase).

Graph Database

Uses graph structures with nodes, edges, and properties to represent and store data (e.g., Neo4j, Amazon Neptune).

Hierarchical Database

Organizes data in a tree-like structure (e.g., IBM Information Management System).

Network Database

Allows many-to-many relationships and more flexible data organization than hierarchical databases (e.g., Integrated Data Store).

ACID Properties

Ensures reliable transactions: Atomicity, Consistency, Isolation, Durability.

Data Definition

Using DDL (Data Definition Language) to define and modify database schema (e.g., CREATE, ALTER, DROP).

Data Manipulation

Using DML (Data Manipulation Language) to insert, update, delete, and retrieve data (e.g., SELECT, INSERT, UPDATE, DELETE).

Data Control

Using DCL (Data Control Language) to manage user permissions and access (e.g., GRANT, REVOKE).

Atomicity

Ensures all operations within a transaction are completed successfully.

Consistency

Ensures the database is in a valid state before and after a transaction.

Isolation

Ensures transactions do not interfere with each other.

Durability

Ensures committed transactions remain so even after a system failure.

Concurrency Control

Manages simultaneous data access to ensure consistency and prevent conflicts.

Data Security

Protects data from unauthorized access and breaches.