dao | 易学教程

Can a DAO call DAO?

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问题 I have component which needs to update the database for the customer and customer address (via JDBC). Is it appropriate to call the CustomerAddressDAO from the CustomerDAO? Or create a separate "CustomerDataManager" component which calls them separately? 回答1: You can do it, but that doesn't mean you should. In these cases, I like to use a Service ( CustomerService in this case) that has a method call that uses both DAOs. You can define the transaction around the service method, so if one call

Mybatis学习笔记(全)

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说明：本文由大量的源代码，及截图，建议读者，操作一遍。ide：IDEA。文末有笔记及视频分享 Mybatis 数据表的sql下载密码: xjjw 1、对原生态jdbc程序（单独使用jdbc开发）问题总结先来看一部分代码 1 Public static void main(String[] args) { 2 3 Connection connection = null; 4 5 PreparedStatement preparedStatement = null; 6 7 ResultSet resultSet = null; 8 9 10 11 try { 12 13 //加载数据库驱动 14 15 Class.forName("com.mysql.jdbc.Driver"); 16 17 18 19 //通过驱动管理类获取数据库链接 20 21 connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf-8", "root", "mysql"); 22 23 //定义sql语句 ?表示占位符 24 25 String sql = "select * from user where username = ?"; 26 27 /

Spring/Spring-Boot 学习 paoding-rose-jade 连接MySQL数据库

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项目依赖新建一个 spring-boot 工程， maven 的 pom 文件中添加如下依赖:  <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> </dependency>  <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency>  <dependency> <groupId>com.54chen</groupId> <artifactId>paoding-rose-jade</artifactId> <version>1.1</version>  <exclusions>

mybatis封装dao层，配置mybatis-config文件

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mybatis-config.xml <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">   <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"> <property name="url" value="jdbc:mysql://localhost:3306/test" /> <property name="username" value="root" /> <property name="password" value="root" /> </bean> <bean id="sqlSessionFactory" class="org

How To Create Generic Data Access Object (DAO) CRUD Methods with LINQ to SQL

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问题 I am new to LINQ to SQL and attempting to create a generic Data Access Object (DAO) for the basic Create, Read, Update, and Destroy (CRUD) methods so that I can reuse the code. I was successful in creating a generic method that will delete any entity by using the code below but, I was wondering if anyone knows how to create a generic method that will select any entity by a common Id field that exists on all tables. /// <summary> /// Generic method that deletes an entity of any type using LINQ

Automatic Hibernate Transaction Management with Spring?

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问题 How far does the spring framework go with transaction handling? My reading of the book "Spring In Action" suggestions with its examples that you create DAO methods that don't worry about Session and Transaction management fairly simply by setting up a session factory and transaction template in XML and then wiring them into your DAO. SpringSource.org's documentation, on the other hand, suggests that need tons of XML and/or annotation to make this happen. What is the truth here, what is the

ORM/DAO/DataMapper/ActiveRecord/TableGateway differences?

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Can you, please, explain me the differences between the following database representatives, say, in PHP.: ORM DAO DataMapper ActiveRecord TableGateway Any examples would be appreciated. That would require a pretty long answer. Instead of repeating what others have said better and in more detail before me, I link you to some relevant pages. I suggest to look through them. Maybe follow a few additional links. Wikipedia is always a good start. If you still have any questions about one or the other pattern after going through the links, feel free to come back to SO and ask again. But if you do,

Hibernate Delete Error: Batch Update Returned Unexpected Row Count

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I wrote this method below that is suppose to delete a member record from the database. But when I use it in my servlet it returns an error. MemberDao Class public static void deleteMember(Member member) { Session hibernateSession = HibernateUtil.getSessionFactory().getCurrentSession(); Transaction tx = hibernateSession.beginTransaction(); hibernateSession.delete(member); tx.commit(); } Controller Part if(delete != null) { HttpSession httpSession = request.getSession(); Member member = (Member) httpSession.getAttribute("member"); MemberDao.deleteMember(member); nextPage = "ledenlijst.jsp"; }

Handling Dao exceptions in service layer

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问题 If my Dao layer throws Dao specific exceptions, then does handling them in my service layer consitute a leakage of concerns? If yes, then should I make the exceptions generic and independent of any layer to address it, or is there some other way? The same question is applicable to UI layer handling exceptions thrown by service layer. 回答1: When we create a layered application, there is always a user layer and another used layer. For this case UI layer -> uses service Layer -> uses DAO layer.

ActiveRecord batch insert (yii2) [closed]

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问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 4 years ago . Is it possible to insert multiple rows in one query with Yii's ActiveRecord? Or is this only possible via the lower-level DAO objects? 回答1: You can use batchInsert() method of yii\db\Command . See details here. When using it with ActiveRecord make sure validate all data before