Database performance issues, solutions, and SQL vs NoSQL comparison. Common Performance Issues 1. Missing Indexes 1-- ❌ Problem: Full table scan 2SELECT * FROM users WHERE email = 'test@example.com'; 3 4-- ✅ Solution: Add index 5CREATE INDEX idx_email ON users(email); 6 7-- Verify index usage 8EXPLAIN SELECT * FROM …

MongoDB queries, aggregation, and Docker setup for document-based NoSQL database. Docker Setup Docker Run 1# Run MongoDB 2docker run -d \ 3 --name mongodb \ 4 -e MONGO_INITDB_ROOT_USERNAME=admin \ 5 -e MONGO_INITDB_ROOT_PASSWORD=password \ 6 -v mongo-data:/data/db \ 7 -p 27017:27017 \ 8 mongo:7 9 10# Connect 11docker …

MySQL commands, optimization, and Docker setup. Docker Setup Docker Run 1# Run MySQL 2docker run -d \ 3 --name mysql \ 4 -e MYSQL_ROOT_PASSWORD=rootpassword \ 5 -e MYSQL_DATABASE=mydb \ 6 -e MYSQL_USER=myuser \ 7 -e MYSQL_PASSWORD=password \ 8 -v mysql-data:/var/lib/mysql \ 9 -p 3306:3306 \ 10 mysql:8 11 12# Connect …

Neo4j graph database queries, algorithms, and vector search capabilities. Docker Setup 1version: '3.8' 2 3services: 4 neo4j: 5 image: neo4j:5 6 container_name: neo4j 7 environment: 8 NEO4J_AUTH: neo4j/password 9 NEO4J_PLUGINS: '["apoc", "graph-data-science"]' 10 NEO4J_dbms_security_procedures_unrestricted: apoc.,gds. …

PostgreSQL advanced features including procedures, views, pgvector for vector similarity search, and Docker setup. Docker Setup Docker Run 1# Run PostgreSQL 2docker run -d \ 3 --name postgres \ 4 -e POSTGRES_PASSWORD=password \ 5 -e POSTGRES_USER=myuser \ 6 -e POSTGRES_DB=mydb \ 7 -v …

SQL language fundamentals - essential commands and patterns for relational databases. Data Definition Language (DDL) CREATE TABLE 1-- Basic table 2CREATE TABLE users ( 3 id SERIAL PRIMARY KEY, 4 username VARCHAR(50) UNIQUE NOT NULL, 5 email VARCHAR(100) UNIQUE NOT NULL, 6 created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP …

Comprehensive comparison of SQL and NoSQL databases to help choose the right database for your use case. Decision Tree graph TD A[Choose Database] --> B{Data Structure?} B -->|Structured, Related| C[SQL] B -->|Flexible, Document| D[NoSQL Document] B -->|Graph Relationships| E[NoSQL Graph] B -->|Key-Value| F[NoSQL KV] C …

SQLite commands for embedded database applications. Basic Commands 1# Create/open database 2sqlite3 mydb.db 3 4# Open in-memory database 5sqlite3 :memory: 6 7# Execute SQL file 8sqlite3 mydb.db < schema.sql 9 10# Dump database 11sqlite3 mydb.db .dump > backup.sql 12 13# Export to CSV 14sqlite3 -header -csv mydb.db …