hbm | 易学教程

Java －－在Eclipse上使用Hibernate

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最近一个项目要用Java做，一点都不熟啊。没办法，只好硬着头皮啃了，花了大半天的时间，终于在Eclipse上完成了第一个Hibernate例子。下面记录关键的步骤，权作笔记，以备日后查看。（1）下载Hibernate，并向项目中导入Hibernate。 Project->Properies->Java Build Path->Libraries->Add External JARs...，选择Hibernate根目录下的hibernate3.jar，添加到项目中。接着，要将Hibernate下的lib文件夹下的所有文件都作为一个User Library添加到项目中，否则，如果仅仅添加hibernate3.jar，编译可以通过，运行却会抛出ClassNotDef的异常，因为hibernate3.jar依赖于Hibernate下的lib文件夹下的文件。 2）我们的应用的后台数据库使用的是Oracle，所以首先要在例子项目中引入含有Oracle jdbc driver的包，classes12.jar。该jar文件位于oracle安装目录的jdbc\lib目录下。在Eclipse中，Project->Properies->Java Build Path->Libraries->Add External JARs...，选择classes12.jar，将其添加到项目中。（3

Hibernate学习——映射关系

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学习记录 O(∩_∩)O 、如果你恰巧路过，希望你能停下脚步瞧一瞧，不足之处望指出，感激不尽~ 使用工具： 1、eclipse 2、hibernate压缩包（hibernate_4.3.11） 3、mysql 准备工作：创建工程——>导入hibernate.jar包——>编写 hibernate.cfg.xml 配置文件连接数据库编写一个类读取hibernate.cfg.xml 一、单向一对多（例子：一个部门有多个员工） 1、建表（Employee员工表和dpet部门表） ①Employee类 ② 配置Employee.hbm.xml 映射文件，并在hibernate.cfg.xml文件中注册（ <mapping resource="com/sw/entity/Employee.hbm.xml"/>） ③ Dept类 ④ Dept.hbm.xml配置文件，并在hibernate.cfg.xml文件中注册（ <mapping resource="com/sw/entity/Dept.hbm.xml"/>） ⑤、创建表方法 2、添加数据：先添加多端数据，再添加一端数据，再让多端中的数据与一端数据进行关联，在数据库中，会先执行insert语句，再执行update语句修改关联关系，效率偏低来源： https://www.cnblogs.com/lady-Mu/p

hibernate4-hbm.xml基本使用-Maven Demo

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目录结构如图， 1.用MyEclipse建立一个Maven-Java项目，然后给出pom配置， <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.xuebaosoft.hibernate4</groupId> <artifactId>hibernate4-maven-conf</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>hibernate4-maven-conf</name> <url>http://maven.apache.org</url> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <

Hibernate Save Object without one column

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问题 I have a table called test and It has columns like id, name, address. I have created POJO class( User ) for all the three columns and same has been mapped with hbm configuration. Here My questions is, How do I prevent one column while saving the User object in session ( session.save(User) ). Let say I dont want to save my address field. How can I prevent. Are there any properties in HIbernate configuration or any modifier needs to be added in POJO? 回答1: Make that field as Transient. Transient

Set creation and update time with Hibernate in Xml mappings

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问题 I'm using Hibernate with Xml mappings. I have an entity that has two fields creationDate and updateDate of type timestamp , that have to be filled with the current UTC time when the entity is persisted and updated. I know about the existence of the @PrePersist and @PreUpdate annotations, but i don't know how to use their equivalent in my Xml mappings. Again, i was wondering if Hibernate somehow supports natively the update and creation time set. Thanks 回答1: I know about the existence of the

could not delete collection : [NHibernate.Exceptions.GenericADOException]

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问题 I have Two Table , tableA and tableB. tableA have column : tabAId, col2, col3 (tabAId primaryKey and Identity column.) tableB have column : tabAId, name (tabAId is not null) I have create Bag in hbm file of tableA, to maintain relation ship. <bag name="tableB" lazy="true" inverse="false" batch-size="25" cascade="all-delete-orphan"> <key column="tabAId" /> <one-to-many class="tableB" /> </bag> When I try to update record in tableA it throw exception, where as I have list of child in tableA

failed.org.hibernate.MappingException: Could not determine type for: String, for columns: [org.hibernate.mapping.Column(db col name)

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问题 I am using Net Beans IDE , When i start to deploy my web project it shows me at the console output an error says: failed.org.hibernate.MappingException: Could not determine type for: String, for columns: [org.hibernate.mapping.Column(db col name) From the message it can not convert types ; I tried to check the types in my files .hbm and .java but no luck so far . The property for which this error is being thrown is defined as <property name="exemptionOwnerName1" type="String"> 回答1: The reason

Fluent NHibernate (1.2.0.712) export mappings to HBM not working / not respecting conventions

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问题 The HBM export function in Fluent NHibernate does not seem to work. If I call FluentMappingsContainer.ExportTo, the generated mappings come out incorrect, and I get the following exception: FluentNHibernate.Cfg.FluentConfigurationException: An invalid or incomplete configuration was used while creating a SessionFactory. Check PotentialReasons collection, and InnerException for more detail. My configuration code looks like this: MsSqlConfiguration database = MsSqlConfiguration.MsSql2008

Breaking changes with NHibernate 4 upgrade

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问题 I can see what's new and fixed in NHibernate 4.0 I would like to know if anyone has had issue with hbm mappings upgrading from NHibernate 3 to 4? I fear that more focus is going on fluent mapping these days. I can test for the more obvious breaking changes but wanted to know if there were any subtle issues that anyone has come across in a production environment that may not be so obvious at first. It looks like a major upgrade and you'd expect there to be the risk of regressions. 回答1: I

由代码生成数据库结构，保障设计正常传递到实现

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【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> 我们常常使用代码生成工具来生成表结构。为什么不试试从代码来生成数据库表结构呢？这个观点有些匪夷所思，但是熟悉Hibernate的同志应该有所体会。Hibernate有一个功能，叫做hbm2ddl,在系统启动时，Hibernate扫描hbm映射文件，检查数据库结构和hbm是否匹配，如果不匹配，则在数据库中增加hbm文件中描述的表或者字段。严格意义上来说，这不是从“代码”生成表结构，而是由“hbm配置文件”生成表结构。后来，当Hibernate支持注解功能后，hbm2ddl也会自动扫描EntityBean上的注解，来与数据库表结构进行匹配。所以，这个hbm2ddl，也算作从代码生成表结构。回到原点，为什么需要从代码生成表结构的功能？我们一般的开发过程，是先做了“数据库设计”，然后在数据库中建表，最后再编写java代码。数据库设计工具，一般提供生成表结构到数据库的功能，也提供生成和表结构对应的javabean功能。【数据库】<-【数据库设计工具】->【JavaBean】如果我们的数据库一次成型，永不改变，每个版本只做代码层面业务逻辑上的变动，那么上面的过程是比较完美的。但实际上，作为一个长期维护的软件系统，数据库设计不变动，是几乎不可能的。那么，当开发下一个版本的时候，我们首先需要变动的是数据库设计文件

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