Seasoned Java and mobile developer with years of experience, specializing in mini‑programs, public accounts, and full‑stack front‑end development. In the AI era, I continuously learn to broaden my knowledge and evolve. I revived a public account I started a decade ago during a dessert‑startup venture, using code as a vessel and knowledge as a companion. I share personal projects, technical articles, programming tips, and growth insights—let’s improve together and set sail.
The article explains what MySQL slow queries are, why they must be detected, when to enable slow‑query logging, step‑by‑step commands to configure the log, how to simulate and analyze problematic SQL with EXPLAIN, and practical optimization techniques—including index creation and Spring Boot integration—to eliminate performance bottlenecks.
This article explains how the SQL UPDATE statement modifies existing rows, emphasizes the necessity of a WHERE clause to avoid full‑table changes, provides single‑row, batch, and multi‑column examples, and advises verifying data with SELECT before executing updates in production.
When query results appear unordered, the SQL ORDER BY clause lets you instantly arrange rows by ascending or descending values—such as timestamps, amounts, or multiple fields—providing clean, organized output for latest‑first displays, statistical sorting, and tidy list presentations.
This article explains MySQL indexes with a simple book‑catalog analogy, shows why missing or mis‑used indexes cause severe latency and CPU issues, outlines when to create or avoid indexes, and provides a step‑by‑step SpringBoot demo that measures query time dropping from 80‑200 ms to under 5 ms.
SELECT is the most frequently used SQL command, handling about 80% of data‑related work; this guide explains its core role, basic operations such as selecting all rows, specific columns, distinct values, and row limits, shows practical code examples, and advises against using SELECT * for better performance.
To keep microservice systems stable, the article explains why fault‑tolerance is essential, defines service avalanches, and details four core safeguards—rate limiting, circuit breaking, degradation, and debounce—covering their principles, typical use cases, deployment layers, and how they work together to prevent cascading failures.
This tutorial explains the purpose of the SQL INSERT statement, compares column‑specified and full‑field syntax, shows single‑row and batch‑row examples using a UserInfo table, and highlights common pitfalls such as column‑value ordering, quoting rules, and auto‑increment IDs.
This tutorial walks beginners through the fundamentals of database tables—explaining fields, data types, and constraints—while demonstrating how to create a standard user table, view its structure, and safely delete it using SQL Server commands.
This tutorial walks SQL newcomers through the three essential database commands—creating a database, listing all databases, switching to a specific one, and safely dropping a database—providing copy‑paste code, practical scenarios, and beginner‑focused pitfalls.
The article explains how to build a production‑grade MQ architecture by addressing the four critical pitfalls—message loss, duplicate consumption, backlog, and out‑of‑order delivery—through producer ACK retries, persistent storage, manual ACKs, idempotent business logic, dead‑letter queues, consumer scaling, and partitioned ordering.
