Polymorphic Indexes in MySQL: Type-First or ID-First?
A practical comparison of [type, id] versus [id, type] composite index order for polymorphic associations in Rails and MySQL, and how to choose.
Tag: mysql
localhost vs 127.0.0.1 vs 0.0.0.0: Network Binding Explained
Why localhost, 127.0.0.1, 0.0.0.0, and * behave differently for MySQL clients and services, and how to find and fix a local port conflict between Docker and SSH.
MySQL vs PostgreSQL: Foreign Key Deadlock Contention
How foreign key checks cause deadlock contention in MySQL InnoDB versus PostgreSQL, and why PostgreSQL's FOR KEY SHARE lock reduces the risk considerably.
Deadlocks in MySQL and PostgreSQL: Foreign Keys vs Performance
How deadlocks form in MySQL and PostgreSQL under concurrent updates, and the trade-off between foreign key integrity and write throughput.
Common MySQL Commands: Databases, Users, and Grants
A quick-reference list of MySQL and MariaDB commands for databases, tables, users, and grants, kept for copy-pasting from the shell.
最令PHP初学者头痛的十四个问题及解决方案
PHP是一门强大且流行的服务器端脚本语言，但初学者在学习过程中可能会遇到一些常见问题。本文将列举并提供这些问题的解决方案。