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01 download resource file The following three JS and CSS resource files are introduced into the project in the BootStrap front-end framework <!-- DataTables --> <script src="/static/assets/bower_components/datatables.net/js/jquery.dataTables.min.js"></script> <script src="/stat ...

## JDBC: 1. Concept: Java DataBase Connectivity, Java language operation database * essence of JDBC: in fact, it is a set of rules defined by the official (sun company) to operate all relational databases, that is, interfaces. Each database manufacturer will implement the socket and provide the da ...

Opening chapter Recently, I have nothing to do at home and started Python language. I have been engaged in Java development, so it is easier to learn Python than to start from scratch. After learning the basic grammar, I made a student management system (necessary for university course design ~), and consolidated the python grammar. Next, I wil ...

General index Key at creation: INDEX KEY when viewing: KEY #Amendment: ALTER TABLE book ADD INDEX BkNameIdx ( bookname(30) ); #In the book table, create a common index on the year [publication] field. The SQL statement is as follows: CREATE TABLE book ( bookid INT NOT NULL, bookname ...

The principle of Mybatis interceptor is a bit convoluted and simple. The principle is to implement agents for our customized interceptor class through the dynamic agent technology of JDK, and there can be multiple agents. Therefore, Mybatis interceptor will exist in the form of a chain, and each agent w ...

Cold and hot backup of database Data export is not exactly equal to data backup: Data export refers to the data in the database is conversed into SQL statements for export, so the export is SQL files. Often used to migrate data from one system to another in order to mask differences between systems Data backup refers to copying the relevant ...

execute(String  sql)    Any sql statement can be executed, but the return value is void, so it is generally used for database creation, modification, deletion and data table record addition, deletion and modification.     int  update(String sql)  int  update(String sql, Object...args) Add, delete, args passes the actual parameter, and retur ...

Operation of database Linked database mysql -u root -proot -- Direct display of password is not recommended mysql -uroot -p Exit database exit/quit The sql statement needs a semicolon at the end; the end Show database version select version(); Display time select now(); View all databases ...

First, a PooledConnection class is created to encapsulate the connection information; package com.bai.pool; import java.sql.Connection; /** * * Copyright: Copyright (c) 2018 LanRu-Caifu * * @ClassName: PooledConnection.java * @Description: Connection information stored in connection pool * * @version: v1.0.0 * @author: Mr ...

In the last blog, I simply said what is distributed lock, and built a basic environment (very simple). This blog needs to start to experience distributed lock formally. Because it is developed on a single machine, there is no cluster, but the specific implementation of the code method is no different fr ...