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1. Why use set For example: storing data Before, you can use arrays to store data. Arrays have great disadvantages. Once the length is determined, it cannot be modified. Therefore, if you delete or add elements, you need to move a lot of elements. Array: only one data type can be put, either basic dat ...

1. Distributed transaction scenario Scene Description: Alipay transfer balance treasure Distributed transactions must meet the following conditions: 1, remote RPC calls, Alipay and bal ...

1. Flow chart: /* ** close at 12 loads ** As you can see from the browser console, the close method actually adds a display:none style ** Just hide the window, not really close it ** In addition, the advantage of loading the window in advance is that when printing, the loading animation will not appear, and the printing method ...

Summary of this section In the previous section, we realized the function of adding books, then this section will mainly realize the function of book maintenance, that is, the query, modification and deletion of book records.   Book maintenance interface First of all, we need to get out the inter ...

Program Functions The main function of this program is to import data from files into the clickhouse database. [Problem Description] Server memory runs out at regular intervals [Problem Analysis] Because it was developed in go language, pprof, a tool popular in the industry, was used. Reference URL:https://cizixs.com/2017/09/11/profiling-golang ...

1, Statement interface introduction Function: object used to execute a static SQL statement and return the result it generates int executeUpdate(String sql) executes the given SQL statement, which may be an INSERT, UPDATE, or DELETE statement, or an SQL statement that does not return anything, such as a SQLDDL statement. vo ...

MyBatis configuring dynamic SQL statements In the SQL mapping file of MyBatis, sometimes you need to select different SQL statements according to some query conditions. If you rewrite SQL in every scenario, it's obvious that the efficiency is not very high, and the dynamic SQL of MyBatis solves this problem well. The dynamic SQL of MyBatis pro ...

In the third part of this series, I used an example to detail the Impala query profile.In this section, I will use an Impala Profile file from a real production system to explain the steps I take to read the Profile file when I encounter a problem and gradually find the real cause of the problem.If you missed the first three parts of my article ...

This paper records the implementation of simple paging function. Relevant environment: Spring boot framework; Template engine: thymeleaf; Front end framework: layui; Framework of persistence layer: mybatis; Paging plug-in: pagehelper; Write some nonsense. (please skip it if you are eager to realize th ...

MyBatis Getting Started to CURD As a happy little farmer, we often repeat different versions at every stage, student management, user management, registered logins, from the console version of JavaSE, or GUI version, to the JSP version of JavaWeb, to the version that just uses HTML as a front-end presentation, and to a newer technology where w ...