不管做什么项目,必须都得接触的东西就是时间类型。现在用时间戳存储日期数据(整型存储)已经是业界很平常的的事情,网上各大游戏公司,各大开源都是采取整型时间戳存储。整数存日期好处很多,程序判断直读,扩展性好,随意可转换xml,json等格式。不过有一个最大的缺点就是查数据库不直观,也就是说我们用管理工具打开数据库的时候,看到的是一堆数字,维护数据不方便。为了解决这一缺陷,我找到一方法,先上代码:
select *,DATE_FORMAT(FROM_UNIXTIME(datetimed/1000),"%Y-%m") from `testTable`
testTable是表名,datetimed是表里一个整型字段。本人用的是毫秒存储,但是mysql的FROM_UNIXTIME方法只能转秒,所以就/1000来计算。
用过织梦,Discuz开源的朋友应该都有过看到一堆头痛的整型时间的经历吧。这段mysql语句粘到管理工具运行就可以直观的看到日期结果了。
但是如果还有人觉得这样麻烦,我无话可说,毕竟有些做小项目的人不需要考虑扩展,也用不上对象格式转换。后台的操作基本用不上Date,都是把Date转成整型再计算,干嘛浪费时间精力存一个不方便转格式的Date型。众多大型开源都使用时间戳,允分证明了时间戳存储的优势。为了一个快一步的直观而放弃扩展,这值吗?

MySQL's position in databases and programming is very important. It is an open source relational database management system that is widely used in various application scenarios. 1) MySQL provides efficient data storage, organization and retrieval functions, supporting Web, mobile and enterprise-level systems. 2) It uses a client-server architecture, supports multiple storage engines and index optimization. 3) Basic usages include creating tables and inserting data, and advanced usages involve multi-table JOINs and complex queries. 4) Frequently asked questions such as SQL syntax errors and performance issues can be debugged through the EXPLAIN command and slow query log. 5) Performance optimization methods include rational use of indexes, optimized query and use of caches. Best practices include using transactions and PreparedStatemen

MySQL is suitable for small and large enterprises. 1) Small businesses can use MySQL for basic data management, such as storing customer information. 2) Large enterprises can use MySQL to process massive data and complex business logic to optimize query performance and transaction processing.

InnoDB effectively prevents phantom reading through Next-KeyLocking mechanism. 1) Next-KeyLocking combines row lock and gap lock to lock records and their gaps to prevent new records from being inserted. 2) In practical applications, by optimizing query and adjusting isolation levels, lock competition can be reduced and concurrency performance can be improved.

MySQL is not a programming language, but its query language SQL has the characteristics of a programming language: 1. SQL supports conditional judgment, loops and variable operations; 2. Through stored procedures, triggers and functions, users can perform complex logical operations in the database.

MySQL is an open source relational database management system, mainly used to store and retrieve data quickly and reliably. Its working principle includes client requests, query resolution, execution of queries and return results. Examples of usage include creating tables, inserting and querying data, and advanced features such as JOIN operations. Common errors involve SQL syntax, data types, and permissions, and optimization suggestions include the use of indexes, optimized queries, and partitioning of tables.

MySQL is an open source relational database management system suitable for data storage, management, query and security. 1. It supports a variety of operating systems and is widely used in Web applications and other fields. 2. Through the client-server architecture and different storage engines, MySQL processes data efficiently. 3. Basic usage includes creating databases and tables, inserting, querying and updating data. 4. Advanced usage involves complex queries and stored procedures. 5. Common errors can be debugged through the EXPLAIN statement. 6. Performance optimization includes the rational use of indexes and optimized query statements.

MySQL is chosen for its performance, reliability, ease of use, and community support. 1.MySQL provides efficient data storage and retrieval functions, supporting multiple data types and advanced query operations. 2. Adopt client-server architecture and multiple storage engines to support transaction and query optimization. 3. Easy to use, supports a variety of operating systems and programming languages. 4. Have strong community support and provide rich resources and solutions.

InnoDB's lock mechanisms include shared locks, exclusive locks, intention locks, record locks, gap locks and next key locks. 1. Shared lock allows transactions to read data without preventing other transactions from reading. 2. Exclusive lock prevents other transactions from reading and modifying data. 3. Intention lock optimizes lock efficiency. 4. Record lock lock index record. 5. Gap lock locks index recording gap. 6. The next key lock is a combination of record lock and gap lock to ensure data consistency.


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