Database performance issues, solutions, and SQL vs NoSQL comparison. Common Performance Issues 1. Missing Indexes 1-- โ Problem: Full table scan 2SELECT * FROM users WHERE email = 'test@example.com'; 3 4-- โ Solution: Add index 5CREATE INDEX idx_email ON users(email); 6 7-- Verify index usage 8EXPLAIN SELECT * โฆ
Read MoreMongoDB 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 โฆ
Read MoreMySQL 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 โฆ
Read MoreNeo4j 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 โฆ
Read MorePostgreSQL 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 โฆ
Read MoreSQL 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 โฆ
Read MoreComprehensive comparison of SQL and NoSQL databases to help choose the right database for your use case. Decision Tree Feature Comparison Feature SQL NoSQL Schema Fixed, predefined Flexible, dynamic Scalability Vertical (scale up) Horizontal (scale out) Transactions ACID guaranteed Eventually consistent (usually) Joins โฆ
Read MoreSQLite 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 โฆ
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