Database
Master relational database theory, SQL, normalization, transactions, concurrency, and modern data systems including NoSQL and data warehousing.
Popular Topics
Relational Model & ER Diagrams
Entities represent real-world objects; attributes describe their properties (simple, composite, single-valued, multi-valued).
SQL Basics
DDL commands (CREATE, ALTER, DROP) define and modify database structure.
Normalization
1NF ensures atomicity of columns and enforces a primary key.
1The Foundation
Relational Model & ER Diagrams
Entities represent real-world objects; attributes describe their properties (simple, composite, single-valued, multi-valued).
SQL Basics
DDL commands (CREATE, ALTER, DROP) define and modify database structure.
Normalization
1NF ensures atomicity of columns and enforces a primary key.
2The Engine Room
Advanced SQL & Query Optimization
Joins (Inner, Outer, Self, Cross) combine rows from multiple tables based on related columns.
Transaction Management & ACID
ACID: Atomicity (all or nothing), Consistency (preserving rules), Isolation (concurrency independence), Durability (persistence).
Concurrency Control
The lost update problem occurs when concurrent transactions overwrite each other's changes.
Database Security & User Management
Authentication verifies identity; authorization grants permissions (privileges).
3The Real World
Storage, Indexing & File Structures
Random I/O is expensive; sequential I/O is fast — this drives index design.
NoSQL Databases
Document stores (MongoDB) store semi-structured JSON-like data with flexible schemas.
Query Processing & Execution Internals
Parsing checks syntax and validates names against the system catalog.
Distributed Databases
Sharding splits tables horizontally across databases by key range or hash.
Data Warehousing & Big Data Concepts
OLTP systems handle transactions (row-store); OLAP systems handle analytics (column-store).