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Requirements: Requirement: update a Date type field in the SQL Server library table to null Environmental Science: SQL Server Version: Microsoft SQL Server 2016 (SP2-CU17) (KB5001092) - 13.0.5888.11 (X64) Mar 19 2021 19:41:38 Copyright (c) Microsoft Corporation Enterprise Edition: Core-based Licensing (64-bit) on Windows Server 2016 Dat ...

MyBatis if is similar to the if statement in Java. It is the most commonly used judgment statement in MyBatis. Using the if tag can save a lot of work in splicing SQL and focus on the maintenance of XML. The if statement is simple to use and is often used in combination with the test attribute. The syntax is as follows. When the judgment con ...

1. Special operation 1.1 fuzzy query Requirement: query the data containing "fine" in name, and arrange it in descending order by age @Test public void test9(){ SqlSession sqlSession = sqlSessionFactory.openSession(true); DemoUserMapper mapper = sqlSession.getMapper(DemoUserMapper.class); Map<String,O ...

        Mybatis has been a professional course in the school for three weeks, and one and a half of them have been studying mapping files. First of all, thank teacher Anna for her guidance. Her teaching is very serious and responsible, and the content is also very rich. However, due to the many and miscellaneous mapping con ...

1, Bicycles Sometimes we may use our own business code to find out a List, and then use sublist for manual paging. Manual paging can make it clear how to use the subList method of List, but this is very desirable. If the return value is too large, the memory is easy to be ruthlessly burst. import dao.TestMapper; import entity.TestEntity; imp ...

Mybatis - Basics ⭐ sketch Mybatis – MyBatis 3 | introduction - official address You can learn from the official address, and most of the content of this article is also quoted here 1 what is mybatis A persistence layer framework, which is also a semi ORM (semi automated) framework, encapsulates JDBC code at the bottom, so that p ...

Build environment Build database table MySQL database is used. Create a new database named task and a new table named student in the task database. Add data to the table as appropriate. The SQL statements for creating tables and adding data are as follows. SET FOREIGN_KEY_CHECKS=0; --Create table DROP TABLE IF EXISTS `student`; CREATE TABLE ...

First, you know what a framework is:          Framework is the reusable design of the whole or part of the system, which is expressed as a group of abstract components and the method of interaction between component instances; Another definition holds that a framework is an application skeleton that can ...

1, Introduction 1.1 what is a clickhouse ClickHouse is a columnar database management system (DBMS) for on-line analysis (OLAP). In the traditional line database system, data is stored in the following order: Data in the same row is always physically stored together. Common line database systems include MySQL, Postgres and MS SQL Server. ...

(1) Preface When you first wrote JDBC, you needed to manually configure connection information by writing SQL statements one by one. Then Mybatis appeared, no more manual configuration of connection information was needed, and the SQL statements were isolated from the code, but Sql was unavoidable. Then Mybatis Plus appeared, which did not eve ...