Programmer Group

Several common ways to install software on Linux: Source code compilationDecompress the compressed package (generally tar.gz)Compiled installation packages (RPM, DPKG, etc.)Online installation (YUM, APT, etc.) The convenience of the above methods increases in turn, but the versatility decreases in turn. For example, downloading compressed pac ...

SQL basics tutorial Statement: the content of this blog is sorted out from Datawhale's punch in learning, and sorted into notes according to the punch in content. For reprint, please contact Datawhale and my authorization, and the reprint source must be indicated. Chapter 3 more complex queries The first two punch in notes introduced th ...

preface: Will MySQL restrict login when there are too many failures to connect to the database? How should the database server deal with violent cracking? This article introduces the connection control plug-in in MySQL. Let's learn the role of this plug-in. 1. Introduction to connection_control plug-in MySQL server contains a plug-in library ...

Tip: the following is the main content of this article. The following cases can be used for reference 1, Introduction 1.1 what are the existing data storage methods? ① Java programs store data (variables, objects, arrays, collections), which are stored in memory and belong to transient state storage. ② File stores data, which is ...

1, What is a transaction          Transaction refers to a program execution unit that accesses and updates various data in the database. MySQL transactions are mainly used to process data with large amount of operations and high complexity.          (1) . four features (ACID): ...

Database benefits Data persistence is realizedUse a complete management system to uniformly manage data, which is easy to query Related concepts of database DB database: the warehouse where data is stored. It holds some columns of organized data. DBMS Database Management System. A database is a container created and operated by a DBMS. Th ...

Comparison of several batch insertion efficiencies of [MyBatis] There are three main methods for batch data processing: Execute a single insert statement repeatedlyforeach   Splicing   sqlBatch processing 1, Preliminary preparation Based on Spring Boot  +  Mysql, and lombok is used to omit get/set. See pom.xml for details ...

1, Design First, docker is installed in the default reader server, as shown below Next, build a mysql master-slave architecture Start two virtual machines with ip 192.168.96.126 and 192.168.96.127126 as the master and 127 as the slave. 2, Pull image docker pull mysql:5.7 If docker pull mysql is used, the latest version of mysql is pu ...

Overall user shopping What are pv (total visits), average daily visits, uv (total number of users), the number of users with purchase behavior, the shopping situation of users and the repurchase rate? User behavior transformation funnel How about the conversion rate of click Add shopping cart purchase links? What is the abandonment rate of s ...

1. Second kill code (most low implementation): //Open transaction @Transactional(rollbackFor = Exception.class) public BaseResponse<?> startSeckillWithLock(Long id, Long userId) { try { return seckill(id, userId); } catch (Exception e) { throw e; } finally { } } p ...