Skip to content

This repository is a helpful guide for anyone working with data. It covers everything you need to know about databases, including SQL and NoSQL databases, making them faster, and keeping them secure. It also has real-world examples to help you understand how to use databases in practice.

License

Notifications You must be signed in to change notification settings

djeada/Databases-Notes

Folders and files

NameName
Last commit message
Last commit date

Latest commit

 
 
 
 
 
 
 
 
 

Repository files navigation

Databases

This repository is an extensive guide for anyone working with data, from beginners to seasoned professionals. It covers a comprehensive range of topics related to databases, including SQL and NoSQL databases, performance optimization, security best practices, and practical applications. Real-world examples are provided to help you understand how to effectively use databases in practice.

Motivation

Throughout my career as an engineer, I have faced numerous challenges such as slow SQL queries, poorly optimized tables, and inefficient database architectures. Recognizing that a deep understanding of databases is essential for building reliable and high-performance data systems, I created this repository. It aims to serve as a comprehensive resource for myself and others to overcome database challenges and advance our skills in database engineering.

By compiling essential concepts, practical tools, and real-world case studies, this guide provides a well-rounded understanding of database systems. Whether you're looking to optimize queries, design robust schemas, or ensure data security, this repository offers valuable insights and actionable knowledge.

Getting Started with Databases

Setting up a database can be challenging, especially if you're new to the field. To help you get started, here are some useful resources:

Online SQL Interpreters

These platforms allow you to practice SQL queries directly in your browser without any local installation:

Sample Databases

Working with sample databases is an excellent way to learn and experiment:

These resources provide a hands-on approach to learning, allowing you to experiment with SQL queries and explore different database systems.

Notes

Introduction to Databases

Topic Description Notes
Databases Introduction An overview of what databases are and their fundamental concepts. Link
Types of Databases Exploring various kinds of databases, such as relational, NoSQL, and more. Link
Database Management Systems (DBMS) Delves into systems that manage databases, their functions, and types. Link
Data Models Discusses different methods of structuring and representing data within a database. Link
Glossary A compilation of key terms and definitions related to databases. Link

Database Design

Topic Description Notes
Requirements Analysis Process of determining user needs and conditions for the development of a new database system. Link
Normalization Techniques to minimize redundancy and dependency by organizing fields and tables of a database. Link
Denormalization Strategies to optimize database performance by selectively introducing redundancy and organizing tables. Link
Indexing Strategies Approaches to optimize the performance of database queries using indexes. Link
Data Integrity and Constraints Ensuring the accuracy and consistency of data in a database and the rules governing permissible operations. Link

SQL

Topic Description Notes
Introduction to SQL An overview of SQL, its history, and its significance in database management. Link
Data Definition Language (DDL) Commands used to define and manage database structures, such as CREATE, ALTER, and DROP. Link
Data Manipulation Language (DML) Commands for accessing and manipulating data, such as SELECT, INSERT, UPDATE, and DELETE. Link
Data Control Language (DCL) Commands related to data security, such as GRANT and REVOKE permissions. Link
Transaction Control Language (TCL) Commands that manage transactions in a database, such as COMMIT, ROLLBACK, and SAVEPOINT. Link
Joins, Subqueries, and Views Techniques to combine data from different tables and create virtual tables or complex queries in SQL. Link
Stored Procedures and Functions Reusable SQL code saved in the database to perform specific tasks or calculations. Link
Triggers Automated actions that are executed in response to specific changes in the database. Link
Hierarchical Data Techniques and strategies to represent tree-like data structures in relational databases. Link

ACID Properties and Transactions

Topic Description Notes
What is a Transaction An overview of what database transactions are and their significance in ensuring reliable data operations. Link
Atomicity Discusses the all-or-nothing nature of transactions, ensuring that operations are either fully completed or fully reverted. Link
Consistency Ensuring that transactions maintain database integrity and do not violate predefined rules or constraints. Link
Isolation How transactions operate independently and how their effects can be isolated from other concurrent transactions. Link
Durability How the results of a transaction are permanent and cannot be lost once committed. Link

Database Storage and Indexing

Topic Description Notes
How Tables and Indexes are Stored on Disk Explores the underlying mechanisms databases use to store tables and indexes on disk, including physical layouts and data structures. Link
Row-based vs. Column-based Databases Compares the two storage formats, discussing the advantages and drawbacks of each in terms of performance and use cases. Link
Primary Key vs. Secondary Key Differentiates between primary and secondary keys, focusing on their roles, characteristics, and impact on performance. Link
Database Pages Explains how databases use pages to store data and facilitate efficient read/write operations. Link
Indexing Provides an overview of indexing strategies, types of indexes, and how they enhance query performance. Link

Distributed Databases

Topic Description Notes
Partitioning Types Different methods of dividing a database into parts and distributing them across a system. Link
Working with Billion-Row Tables Techniques and best practices for efficiently handling and querying massive tables. Link
Consistent Hashing A technique used in distributing data across multiple servers, ensuring minimal rehashing when servers change. Link
Sharding The process of breaking up large tables into smaller chunks and distributing them across multiple servers. Link
Partitioning vs. Sharding Discussing the differences, similarities, and appropriate use-cases for partitioning and sharding. Link
CAP Theorem A principle outlining the trade-offs between consistency, availability, and partition tolerance in distributed databases. Link
Eventual Consistency A consistency model that ensures all replicas eventually converge to the same value. Link
Distributed Database Systems Overview of systems and architectures that support databases spread across multiple machines or locations. Link

Concurrency Control and Locking

Topic Description Notes
Shared vs. Exclusive Locks Differences between shared and exclusive locking mechanisms. Link
Deadlocks Understanding and resolving situations where locks block each other. Link
Two-Phase Locking The protocol for acquiring and releasing locks to ensure consistency. Link
Double Booking Problem Issues arising from concurrent transactions booking the same resource. Link
Serializable vs. Repeatable Read Discusses the differences between isolation levels and their impact on concurrency and consistency. Link

Database Performance and Optimization

Topic Description Notes
Query Optimization Techniques Methods to enhance the efficiency of database queries. Link
Indexing Strategies Techniques for using indexes to speed up query performance. Link
Database Caching Storing data in cache to improve retrieval times. Link
Materialized Views Precomputed views for faster data access. Link
Accessing Databases in Code Best practices for database interactions within applications. Link

Database Replication

Topic Description Notes
Introduction to Replication Overview of database replication concepts. Link
Master-Standby Replication Exploring the master-standby replication method. Link
Multi-Master Replication Delving into multi-master replication techniques. Link
Synchronous vs. Asynchronous Replication Comparing synchronous and asynchronous replication. Link

NoSQL Databases

Topic Description Notes
Introduction to NoSQL Databases Introduction to non-relational database concepts. Link
Types of NoSQL Databases Overview of various NoSQL database types, such as key-value stores, document stores, column-family stores, and graph databases. Link
Querying NoSQL Databases Techniques for querying non-relational databases. Link
CRUD Operations in SQL vs. NoSQL Differences in CRUD operations between SQL and NoSQL databases. Link

Database Security and Best Practices

Topic Description Notes
Backup and Recovery Strategies Strategies to backup and restore database data. Link
Database Security Measures to protect data and maintain its integrity. Link
Capacity Planning Predicting and addressing database growth needs. Link
Database Migration Process of moving a database from one environment to another. Link
Performance Monitoring and Tuning Observing and optimizing database performance. Link
Real-life Challenges Practical issues faced when managing databases. Link
SQL Injection A type of security vulnerability in database applications. Link

Database Engines

Topic Description Notes
SQLite A lightweight, serverless SQL database engine commonly used in mobile apps and small-scale applications. Link
MySQL A widely-used, open-source relational database management system known for its performance and reliability. Link
PostgreSQL An advanced, open-source relational database system supporting complex queries and data types. Link
MongoDB A popular NoSQL database designed for scalability and flexibility, using JSON-like documents. Link
Neo4j A leading graph database that uses nodes and relationships to represent and store data for complex relationship querying. Link
AWS Database Services Overview of Amazon Web Services' database offerings, covering both relational and non-relational services like Amazon RDS, DynamoDB, and Aurora. Link
Choosing the Right Database Guidelines and factors to consider when selecting a database engine for specific application needs and scenarios. Link

Additional Topics

To further enhance your understanding of databases, consider exploring the following topics:

Big Data and Data Warehousing

Topic Description Notes
Data Warehousing Concepts and architectures for data warehouses used in large-scale data analytics. Link
Hadoop and HDFS An introduction to Hadoop and the Hadoop Distributed File System for big data storage and processing. Link
Spark SQL Using Apache Spark for large-scale data processing with SQL queries. Link

Object-Relational Mapping (ORM)

Topic Description Notes
Introduction to ORM Understanding how ORMs bridge the gap between object-oriented programming and relational databases. Link
Popular ORM Tools Overview of popular ORM tools like Hibernate, Entity Framework, and SQLAlchemy. Link
Advantages and Disadvantages of ORMs Discussing when to use ORMs and potential performance considerations. Link

References

Star History

Star History Chart


This repository is a living document and will be continually updated with new topics and resources. Contributions are welcome!

About

This repository is a helpful guide for anyone working with data. It covers everything you need to know about databases, including SQL and NoSQL databases, making them faster, and keeping them secure. It also has real-world examples to help you understand how to use databases in practice.

Topics

Resources

License

Stars

Watchers

Forks

Releases

No releases published

Packages

No packages published

Languages