orm | 易学教程

What is Object/Relational mismatch

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问题 I am a newbie to java and was reading about Object Relational Mapping. I found a term Object/Relational mismatch on this link Hibernate Can anyone explain what is Object/Relational mismatch in terms of Java. I also read about it from haacked.com but could not get it properly.Explanation with example would be appreciable. 回答1: Hibernate is an ORM (Object-Relational Mapping) tool. Its primary purpose is to translate concepts from object-oriented programming, such as classes, inheritance and

Translate SQLite query, with subquery, into Peewee statement

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问题 I've got a SQL statement that does what I need, but I'm having trouble converting it into the correlated Peewee statement. Here's the SQL I have now, note that I'm using a subquery right now, but I don't care that it's a subquery either way. select t.name, count(a.type_id) as total, ( select count(id) from assignment a where a.course_id = 7 and a.due_date < date() and a.type_id = t.id group by a.type_id order by a.type_id ) as completed from assignment a inner join type t on t.id = a.type_id

DotNet中的数据持久层框架

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下面是DotNet中的数据持久层框架（ORM，半ORM等）的列表： .NET Persistence BBADataObjects DataObjects.NET Data Tier Modeler for .NET DotNorm Eldorado.NET Enterprise Core Objects (ECO™) Entity Broker eXpress Persistent Objects for .NET FastObjects.NET JC Persistent Framework LLBLGen Pro ModelWorks Nhibernate Nolics.NET Norm Norpheme ObjectBroker ObjectSpaces ObjectSpark Objectz.NET OJB.NET OPF.Net (Object Persistent Framework) ORM.NET Pragmatier Data Tier Builder RapTier Sisyphus Persistence Framework TierDeveloper Bob.NET ObjectPersistor.NET Genome Ibatis easyobjects 这么多的框架成熟的不多，各自的设计理念也不太一样。这些框架里我了解的不多。

How to register ORMObjectListener in Intershop7

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问题 We have implemented several custom ORM objects in our webshop implementation that have references (dependencies) to Intershop Product system object. When a user tries to delete a certain product in back-office, it causes problems because references to that product may still exist in our custom objects. Naturally, deleting a product that is referenced from one of our custom objects generates an exception like this: java.sql.SQLTransactionRollbackException: ORA-02091: transaction rolled back

Mybatis知识点总结

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1.什么是MyBatis？答：MyBatis是一个可以自定义SQL、存储过程和高级映射的持久层框架。 2.MyBatis的缓存答：MyBatis的缓存分为一级缓存和二级缓存,一级缓存放在session里面,默认就有,二级缓存放在它的命名空间里,默认是不打开的,使用二级缓存属性类需要实现Serializable序列化接口(可用来保存对象的状态),可在它的映射文件中配置 3.Mybatis是如何进行分页的？分页插件的原理是什么？ 1）Mybatis使用RowBounds对象进行分页，也可以直接编写sql实现分页，也可以使用Mybatis的分页插件。 2）分页插件的原理：实现Mybatis提供的接口，实现自定义插件，在插件的拦截方法内拦截待执行的sql，然后重写sql。举例：select * from student，拦截sql后重写为：select t.* from （select * from student）t limit 0，10 推荐看起来比较清晰的PageHelper分页原理 3)PageHelper首先将前端传递的参数保存到page这个对象中，接着将page的副本存放入ThreadLoacl中，这样可以保证分页的时候，参数互不影响，接着利用了mybatis提供的拦截器，取得ThreadLocal的值，重新拼装分页SQL，完成分页。 4.Mybatis的插件运行原理

conditions for accessors in Coldfusion ORM

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问题 Once you have loaded a component are you then able to access properties of that object with set conditions? For instance, if you have a one-to-many relationship between people and pets, you load people specifying a particular person, you then want to pull all said persons pets where the pets are of a particular species. cats vs dogs for instance. <cfset person=EntityLoad("person", {name="#URL.name#"})> <cfset pets=person[1].getPets()> is there anyway to call getPets where type='dog' or

Hibernate loading all entities utilizing 1st or 2nd level cache

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问题 We have an entire table of entities that we need to load during a hibernate session and the only way I know to load all entities is through an HQL query: public <T> List<T> getAllEntities(final Class<T> entityClass) { if (null == entityClass) throw new IllegalArgumentException("entityClass can't be null"); List<T> list = castResultList(createQuery( "select e from " + entityClass.getSimpleName() + " e ").list()); return list; } We use EHcache for 2nd level caching. The problem is this gets

Hibernate - encrypted reference by relations on usernames

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问题 I was wondering if my idea is possible with hibernate. What I want is that there is one table with usernames and every table wich has a reference to this table has the username encrypted in a column. So the username doesn't stand in normal text but encrypted in every table which have a reference to the user table. So I need something like: @ManyToOne @JoinColumn(name = "userName", insertable=false, updatable=false, encrypted="md5") public User getUser(){ return this.user; } public void

Does Eloquent ORM(laravel 5) take care of SQL injection?

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问题 I couldn't find it online, but does Eloquent ORM take care of SQL injection like PDO prepared statements do? 回答1: As per your question all the eloquent queries are taken care of for SQL injection, because they use the PDO driver in core. So you don't have to worry, but the input are stored as they are so you might want to sanitize as per your application's needs (HTML formatting, etc.) 回答2: No framework "takes care of" SQL injection. You take care of SQL injection. A framework may provide

Doctrine 2.0 ready for use?

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问题 I'm working on a small project (some mark tracking software for a school subject department - PHP frontend with a sqlite DB) and have decided to use ORM. I've taken a look at RedBeanPHP but it seemed a bit too limited for my liking. As such, I've decided to give Doctrine a go. My only prior experience with ORM is LINQ to SQL in .NET. Anyway, I was wondering if I should get started with Doctrine 2.0 (which is in beta at the moment) or if I should take sometime to learn 1.2. I'm looking for