ADevGuide Tag: SQL
All the articles with the tag "SQL".
-
Why Is My SQL Query Slow? A Backend Debugging Guide
Series: Backend Interview Mastery
Learn why SQL queries are slow and use EXPLAIN ANALYZE, query plans, indexes, and production evidence to fix them safely.
-
Database Deadlocks: Causes, Detection, and Prevention
Series: Backend Interview Mastery
Learn database deadlocks through transaction examples, wait-for cycles, retries, lock ordering, query design, and production prevention practices.
-
Optimistic vs Pessimistic Locking: How to Choose
Series: Backend Interview Mastery
Compare optimistic vs pessimistic locking with SQL examples, conflict handling, retries, deadlocks, and practical backend trade-offs.
-
Database Isolation Levels Explained With Real Transaction Examples
Series: Backend Interview Mastery
Learn database isolation levels through real transaction examples, including dirty reads, phantoms, write skew, retries, and SQL trade-offs.
-
Composite Index Column Order: How to Choose the Right SQL Index
Series: Backend Interview Mastery
Learn how to choose composite index column order for SQL queries using equality, range, sort, selectivity, and EXPLAIN plan trade-offs.
-
SQL vs NoSQL: How to Choose in System Design
Series: Database Fundamentals , Backend Interview Mastery
Compare SQL vs NoSQL for system design: data modeling, transactions, scale, trade-offs, and the right database for each workload.
-
Database Indexing Explained: SQL Examples and Interview Questions
Series: Database Fundamentals , Backend Interview Mastery
Learn database indexing with SQL examples: B-tree indexes, query plans, composite index order, write costs, and interview questions.
-
What Is Database Connection Pooling and Why It Matters
Series: Database Fundamentals
Learn what database connection pooling is, how it works under the hood, and why it is essential for building performant, scalable backend applications.
-
How ORMs Work Internally: A Simple Explanation
Series: Database Fundamentals
Learn how Object-Relational Mappers work under the hood - from query building and identity maps to lazy loading and the N+1 problem.
-
What Is a Database Transaction? Step-by-Step Guide
Series: Database Fundamentals
Learn what a database transaction is, how BEGIN, COMMIT, and ROLLBACK work, and when to use savepoints with clear SQL examples.