• Rethink MySQL transactions


    What is business? Is a set of atomic SQL queries, or a separate unit of work. Statements within a transaction are either executed or not executed at all. Scene simulation: Transfer 1000 yuan from user a to user B User a – 1000 yuan User B + 1000 yuan If all of the above operations […]

  • 03. Isolation level of MySQL database transactions


    affairIt is to ensure that a set of database operations are either all successful or all failed. In mysql, transaction support is implemented in the engine layer MySQL is a multi engine system, but not all engines support transactions.For example, MySQL’s native MyISAM engine does not support transactions, which is one of the important reasons […]

  • The difference between dirty reading, non repeatable reading and unreal reading of database


    1. Acid of database In the database, transactions should satisfy acid, that is, a: atomicity, C: consistency, I: isolation, D: persistence. Among them, isolation is the most relaxed one. The database lock mechanism or version and control mechanism can be used to obtain a higher isolation level. However, with the improvement of isolation level, the […]

  • PHP code audit foundation – Advanced


    Advanced part 1. Be familiar with the historical version vulnerabilities of each open source framework. 2. Business logic vulnerability 3. Vulnerabilities caused by multithreading 4. Vulnerability caused by transaction lock   There are a lot of loopholes in advanced audit, which normally do not exist, only in special cases.   PHP common framework Zendframwork,Yii,Laravel ,、ThinkPHP For […]

  • Java snail


      Preface: Consistency means that the integrity constraints of the database are not broken before and after the transaction. This means that database transactions cannot destroy the integrity of relational data and the consistency of business logic. Example: for a bank transfer transaction, no matter whether the transaction succeeds or fails, the total deposit amount […]

  • Redis transaction and expiration time


    Redis transaction and expiration time I. Redis transactions: Transaction is supported in Redis. Transaction means that when we need to execute several commands, either they are not executed or they are executed: 1. Start Transaction Writing: multi 2. Then write the command. Pay attention to every command to be executed after writing. The command will […]

  • ACID features of database transactions (atomicity, consistency, isolation, persistence)


    ACID features: Atomicity, Consistency, Isolation, Durability Atomicity: a transaction must be regarded as an indivisible minimum unit of work. All operations in the whole transaction are either successfully committed or rolled back. The transaction is either successful (visible) or failed (invisible). There is no partial success of the transaction. For a transaction, it is impossible […]

  • Brief Analysis of Transactions in MySQL


    What is a transaction? Transaction is a database operation in which there are only two results, success or failure, there is no theory of half success. Classic cases: Bank transfer:_Account A needs to transfer 1000 yuan to Account B. After analysis, the operation needed is the balance of Account A – 1000 yuan and the […]

  • Summary of 100 MySQL Common Interview Questions


    Preface This article is mainly for developers, so it does not involve MySQL service deployment and other operations, and more content, we are ready for patience and melon seed mineral water. A while ago, I studied MySQL systematically, and had some practical experience. I came across an interview article related to MySQL. I found that […]

  • How to Use Transactions in Redis Basic Tutorials


    How to Use Transactions in Redis Basic Tutorials Redis transactions can execute multiple commands at a time with the following two important guarantees: A transaction is a separate isolated operation: all commands in a transaction are serialized and executed sequentially. During the execution of a transaction, it will not be interrupted by command requests sent […]

  • MySql Learning Notes IV


    MySql Learning Notes IV 5.3. Data types Numerical type integer decimal Fixed-point number Floating point number Character Shorter text: char, varchar Long text: text, blob (long binary data) Date type Principle: The simpler the type chosen, the better the smaller the type that can hold the value. 5.3.1. NUMERICAL MODEL Integer Tinyint: A byte […]

  • Database Storage Engine


    Catalog Database Storage Engine What is a storage engine? What storage engines does MySQL support? Characteristics of various storage engines Common Storage Engines and Applicable Scenarios Interview questions Database Storage Engine What is a storage engine? Data in MySQL is stored in files (or memory) using various technologies. Each of these technologies uses different storage […]