Hand-in-hand as a JSP starter (6): Get the details of a single product

Get details of a single commodity Expanding BookDAO Class to Acquire Book Information Based on isbn Value The realization and acquisition of all commodities are very similar. A parameter property of a PreparedStatment is also used here. public Book getBookByISBN(String isbn){ Connection conn = null; PreparedStatement preStmt = null; ...

Posted on Fri, 29 Mar 2019 13:18:29 -0700 by BenGilbert

Thinking in SQL Series IV: Data Mining C4.5 Decision Tree Algorithms

C4.5 is a series of applications machine learning Classification of Data Mining algorithm . Its goal is supervised learning: given a data set, each tuple can be described by a set of attribute values, and each tuple belongs to a class of mutually exclusive categories. The goal of C4.5 is to accumulate experience and serve for subsequent deci ...

Posted on Thu, 28 Mar 2019 01:48:30 -0700 by ktsirig

Login and Upgrade Modules of Privilege Management System Series

Reference page: http://www.yuanjiaocheng.net/CSharp/Csharp-structure.html http://www.yuanjiaocheng.net/CSharp/Csharp-enum.html http://www.yuanjiaocheng.net/CSharp/Csharp-stringbuilder.html http://www.yuanjiaocheng.net/CSharp/csharp-array.html http://www.yuanjiaocheng.net/CSharp/Csharp-multi-dimensional-array.html Catalog Preface to Privilege Ma ...

Posted on Wed, 27 Mar 2019 14:51:28 -0700 by 2kau

Implementation of Panju Recommendation System Based on Flask and MySQL (2)

Implementation of Recommendation System Introduction to the experiment 1.1 Introduction to Experiments In this section, we will implement the core part of the recommendation system on the basis of the previous section. 1.2 Knowledge Points In this section, we will learn and practice the following knowledge points: Use of Jinj ...

Posted on Wed, 27 Mar 2019 14:39:28 -0700 by Vibralux

[explain] Driver tables in MySQL join table queries

Written in front 1. Everyone is not required to understand the mysql operation process of join/left join/inner join, etc. 2. It is not necessary for everyone to know which tables have a large amount of data and which tables have a small amount of data online (now or in the future). 3. But it's a virtue to put mysql cli ...

Posted on Wed, 27 Mar 2019 10:18:30 -0700 by peterg0123

Mybatis - Advantages and Disadvantages of Level 2 Caching

Deep understanding of MyBatis secondary caching I. The Complete Process of Creating Cache Let's start with the SqlSessionFactoryBuilder parsing mybatis-config.xml configuration file: Reader reader = Resources.getResourceAsReader("mybatis-config.xml"); SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader); ...

Posted on Wed, 27 Mar 2019 09:51:28 -0700 by dellvostro

Detailed Explanation of Three Level Linkage Selection in WheelView Area

1. effect Recently, I need to do a function of area selection, but I haven't found a satisfactory one on the Internet and github for a long time. Then my friend recommended one to me. I spent some time to read the code roughly and change it to what I want, and write down my understanding. The effect is as follows: 2. pay attention to a. ...

Posted on Tue, 26 Mar 2019 17:45:30 -0700 by Bizzle

A simple implementation of annotation-based orm (1)

Let's start with a common database operation code: protected User getDataFromDatabase(long id){ String sql = "select firstname from user where id=?";//1 Connection conn = DBConnectionFactory.getConnection(); PreparedStatement stat; User user;//2 try { stat = conn.prepareStatement(sql); ...

Posted on Tue, 26 Mar 2019 03:45:31 -0700 by matt_4013

T-SQL Statement (6) - Trigger Operation

T-SQL Statement (6) - Trigger Operation Introduction of Triggers 1. Functions of triggers: a. Implementing data constraints that are more complex than constraints b. Can check whether the operation done by SQL is allowed c. Modifying the data of tables in other databases d. Multiple stored procedures can be invoked at one time e. Send S ...

Posted on Mon, 25 Mar 2019 17:21:28 -0700 by discobean

Sql common grammar

Classification of SQL DDL - Data Definition Language (CREATE, ALTER, DROP, DECLARE) DML - Data Manipulation Language (SELECT, DELETE, UPDATE, INSERT) DCL - Data Control Language (GRANT, REVOKE, COMMIT, ROLLBACK)   II. Basic Sentences 2.1. Description: Create a database create database db-name 2.2. Note: Delete the database drop database db-n ...

Posted on Mon, 25 Mar 2019 15:15:30 -0700 by Schneider707