MySQL SQL Optimization
The core goal of SQL optimization is to reduce full table scans, make full use of indexes, and lower database resource consumption, ultimately improving query and write efficiency. High-Frequency SQL …
MySQL (CAP Theorem)
Definition The CAP theorem (also called the CAP principle) is a core guideline for distributed system design, proposed by computer scientist Eric Brewer. Its central conclusion: a distributed system c…
Summary of MySQL Basic and Advanced Knowledge
How to get the names and types of all columns in a table How to create and drop tables Use create table to create a table and drop table to drop a table: How to create and drop databases How to view a…
Alipay Payment Wrapper (For Understanding Internal Workflow)
src/config.php src/Rsa.php src/Base.php src/AliPay.php src/Notify.php src/Return.php Root Entry: index.php (Initiate Payment) Root Entry: notify.php (Asynchronous Notification) Root Entry: return.php …
A Gentle Look at EXPLAIN
Overview EXPLAIN is the core tool in MySQL for analyzing SQL execution plans. It simulates the optimizer's process of executing an SQL statement and outputs execution details, such as whether an index…
MySQL Deadlocks
Core Principles Deadlock = opposite lock ordering + circular waiting. For example, transaction A locks row 1 then waits for row 2, while transaction B locks row 2 then waits for row 1 — each waits on …
MySQL Locks
What Are Locks Locks are the mechanism databases use to manage "multiple transactions concurrently accessing the same data", and a key feature distinguishing databases from ordinary file systems. With…
PHP's Composition and Lifecycle
Understanding PHP can't stop at "writing a few functions". From a PHP request being caught by the web server to the final response output, a whole set of kernel components must cooperate, and the requ…
MySQL Transactions
What Is a Transaction Definition of a Transaction A transaction is a sequence of operations in the database that either all execute successfully or all don't (all are undone) — there's no "half-done" …
MySQL Development Standards
Table Creation Standards Naming and Comments Database / table / column names use lowercase letters or digits, no leading digits Database names, table names, and column names must all be lowercase lett…
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