contains a set of statements to configure various SQL statements such as select, insert, update, and delete. These statements are known as Mapped Statements or Mapped SQL Statements. All the statements have update("Student.update",student); Delete To delete the values of an existing record using MyBatis, the mapped query ‘delete’ is configured. The attributes of ‘delete’ mapped query are same as the insert example of the delete mapped query − <delete id = "deleteById" parameterType = "int"> DELETE from STUDENT WHERE ID = #{id}; delete> You can invoke the delete mapped query using the delete method of SqlSession

XML配置 XML配置 XML映射文件 XML映射文件 查询(select) 查询(select) 更新(insert, 更新(insert, update and update and delete) delete) 参数 参数 (Parameters) (Parameters) 结果集 结果集 (Result (Result Maps) Maps) 自动映射 自动映射 (Auto- (Auto- 已废弃！老式风格的参数映射。内联参数是首选,这个元素可能在将来被移除，这里不会记录。 sql – 可被其他语句引用的可重用语句块。 insert – 映射插入语句 update – 映射更新语句 delete – 映射删除语句 select – 映射查询语句 下一部分将从语句本身开始来描述每个元素的细节。 select 查询语句是 MyBatis 中最常用的元素之一，光能把数据存到数据库 果集给一个名称，名称是逗号分隔 的。 insert, update 和 和 delete Your visitors can save your web pages as PDF in one click with http://pdfmyurl.com! 数据变更语句 insert，update 和 delete 的实现非常接近：

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into users(name, age) values(#{name}, #{age}); <delete id="deleteUser" parameterType="int"> delete from users where id=#{id} delete> Delete("delete from users where id=#{id}") public int deleteUserById(int id); @Update("update users set name=#{name} 资料下载，可访问尚硅谷（中国）官网 www.atguigu.com 下载区】 3). 补充说明 1. 映射语句文件中的所有 select 语句将会被缓存。 2. 映射语句文件中的所有 insert，update 和 delete 语句会刷新缓存。 3. 缓存会使用 Least Recently Used（LRU，最近最少使用的）算法来收回。 4. 缓存会根据指定的时间间隔来刷新。 5. 缓存会存储 1024 个对象

selected table must be the same or binding tables UPDATE tbl_name SET col1 = ? WHERE col2 = ? DELETE FROM tbl_name WHERE col1 = ? CREATE TABLE tbl_name (col1 int, ⋯) ALTER TABLE tbl_name ADD col1 into a primary database and a replica database. The primary database is responsible for the insert, delete and update of trans‐ actions, while the replica database is responsible for queries. It can significantly instances and other things. /status/storage_nodes It is able to orchestrate replica database, delete or disable data dynamically. Dynamic Effectiveness Modification, deletion and insertion of relevant

selected table must be the same or binding tables UPDATE tbl_name SET col1 = ? WHERE col2 = ? DELETE FROM tbl_name WHERE col1 = ? CREATE TABLE tbl_name (col1 int, ⋯) ALTER TABLE tbl_name ADD col1 into a primary database and a replica database. The primary database is responsible for the insert, delete and update of trans‐ actions, while the replica database is responsible for queries. It can significantly SELECT/UPDATE/DELETE 4.9. Shadow DB 61 Apache ShardingSphere document, v5.1.1 • Condition* SQL S upp ort ed = SELECT/UPDATE/DELETE ⋯ WHERE column = value Y LIKE/NOT LIKE SELECT/UPDATE/DELETE ⋯ WHERE

selected table must be the same or binding tables UPDATE tbl_name SET col1 = ? WHERE col2 = ? DELETE FROM tbl_name WHERE col1 = ? CREATE TABLE tbl_name (col1 int, ⋯) ALTER TABLE tbl_name ADD col1 into a primary database and a replica database. The primary database is responsible for the insert, delete and update of trans‐ actions, while the replica database is responsible for queries. It can significantly where column1 = value1 N • SELECT/UPDATE/DELETE • Condition* SQL S upp ort ed = SELECT/UPDATE/DELETE ⋯ WHERE column = value Y LIKE/NOT LIKE SELECT/UPDATE/DELETE ⋯ WHERE column LIKE/NOT LIKE value

exist in current sharding, they will not have any influence on data, but insert operation has to delete extra sharding keys. Take the following SQL for example: INSERT INTO t_order (order_id, xxx) VALUES the table se‐ lected must be the same or bind tables UPDATE tbl_name SET col1 = ? WHERE col2 = ? DELETE FROM tbl_name WHERE col1 = ? CREATE TABLE tbl_name (col1 int, ⋯) ALTER TABLE tbl_name ADD col1 ShardingSphere document, v5.0.0-beta /states/datanodes It is able to orchestrate replica database, delete or disable data dynamically. Dynamic Effectiveness Modification, deletion and insertion of relevant

相同的包下 2、持久层映射配置中 mapper 标签的 namespace 属性取值必须是持久层接口的全限定类名 3、SQL 语句的配置标签,,<delete>,的 id 属性必须和持久层接口的 方法名相同。 2.1 根据 ID 查询 2.1.1 在持久层接口中添加 findById 方法 /** * 根据 userId); 2.4.2 在用户的映射配置文件中配置 <delete id="deleteUser" parameterType="java.lang.Integer"> delete from user where id = #{uid} delete> 2.4.3 加入删除的测试方法 @Test public void testDeleteUser() deleteUser(Integer userId) { SqlSession session = factory.openSession(); int res = session.delete("com.itheima.dao.IUserDao.deleteUser",userId); session.commit(); session.close();

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Apache ShardingSphere 5.2.1 Document

into a primary database and a replica database. The primary database is responsible for the insert, delete and update of trans‐ actions, while the replica database is responsible for queries. It can significantly Namespace 3.3.6 Core Concept Primary database The primary database is used to add, update, and delete data operations. Currently, only single primary database is supported. Secondary database The sup‐ port • SELECT/UPDATE/DELETE • condition ca tegories* SQL • support or not* = SELECT/UPDATE/DELETE ⋯ WHERE column = value support LIKE/NOT LIKE SELECT/UPDATE/DELETE ⋯ WHERE column LIKE/NOT

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Apache ShardingSphere 5.2.0 Document

into a primary database and a replica database. The primary database is responsible for the insert, delete and update of trans‐ actions, while the replica database is responsible for queries. It can significantly Namespace 3.3.6 Core Concept Primary database The primary database is used to add, update, and delete data operations. Currently, only single primary database is supported. Secondary database The not sup‐ port • SELECT/UPDATE/DELETE 3.9. Shadow 49 Apache ShardingSphere document, v5.2.0 • condition ca tegories* SQL • support or not* = SELECT/UPDATE/DELETE ⋯ WHERE column = value support

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