metamodel

How to generate plug-in using .ecore metamodel

由 試著忘記壹切 提交于 2021-01-27 18:17:12
问题 I have 2 files, an ecore implementation metamodel and an e-Repository. The e-Repository is provided in EMF format together with the ecore implementation metamodel. I want to browse the contents of this repository and all I know is that I have to generate an Eclipse plugin from the implementation metamodel and with this plugin, I can open the repository and browse its content. But I have no idea how to generate the plugin and proceed with it. The ecore implementation metamodel was developed

【收藏】关于元数据(Metadata)和元数据管理，这是我的见过最全的解读！

由 耗尽温柔 提交于 2020-12-24 17:49:49
本文主要从元数据的定义、作用、元数据管理现状、管理标准和元数据管理功能等方面讲述了我对元数据(Metadata)和元数据管理的认知及理解。 元数据管理 一、元数据的定义 按照传统的定义，元数据（Metadata）是关于数据的数据。在数据仓库系统中，元数据可以帮助数据仓库管理员和数据仓库的开发人员非常方便地找到他们所关心的数据；元数据是描述数据仓库内数据的结构和建立方法的数据，可将其按用途的不同分为两类：技术元数据（Technical Metadata）和业务元数据（Business Metadata）。 技术元数据 技术元数据是存储关于数据仓库系统技术细节的数据，是用于开发和管理数据仓库使用的数据，它主要包括以下信息： 数据仓库结构的描述，包括仓库模式、视图、维、层次结构和导出数据的定义，以及数据集市的位置和内容； 业务系统、数据仓库和数据集市的体系结构和模式； 汇总用的算法，包括度量和维定义算法，数据粒度、主题领域、聚集、汇总、预定义的查询与报告； 由操作环境到数据仓库环境的映射，包括源数据和它们的内容、数据分割、数据提取、清理、转换规则和数据刷新规则、安全（用户授权和存取控制）。 业务元数据 业务元数据从业务角度描述了数据仓库中的数据，它提供了介于使用者和实际系统之间的语义层，使得不懂计算机技术的业务人员也能够“读懂”数据仓库中的数据。业务元数据主要包括以下信息

阿里架构师的灵魂拷问：你真的懂SOA吗？

由 孤人 提交于 2020-08-14 16:50:26
如何统一看待和区别分层架构、微服务架构、分布式架构等主流架构？什么是 SOA？我们采用 SOA 的目的是什么？什么是服务化的本质？如何设计服务以及服务化架构呢？本文，阿里高级技术专家程彦将分享他对面向服务架构的一些看法，并给出相关的步骤和方案。 自从提倡 SOA 架构风格以来，个人觉得软件架构并未有特别突破的变革，主要是在 SOA 面向服务架构风格基础上不断演化迭代，基于服务的 EA 明确分层架构也好，微服务也罢，都是在面向服务架构基础上的适应不同的场景的迭代升级。 我先抛出一个观点，我觉得服务化架构的本质，和西方教育界深受影响的古希腊哲学家苏格拉底的“产婆术”的教育思想本质上是非常相通的：苏格拉底的“产婆术”思想强调教育是一个“接生”的过程，教师就是“接生婆”，人们之所以接受教育是为了寻找“原我”以不断完善自身。也就是教育的目的在于唤醒而不再于塑造。 同理服务化架构的本质也不仅仅在采用什么样的技术框架实现和塑造，更重要的是在于通过不停地在共创中反问、反思、反省等方式进行对业务的本质的不断追溯、抽象、综合归纳演绎，我们的每一个架构师都是服务化架构的接生婆，我们的使命是建立真正反映业务本质并驱动业务不断向前的架构。 我们是否足够深入理解业务的本质，做了足够的归纳演绎以及综合抽象，是否清晰的反应到了我们的服务化的根基：业务模型、域模型以及平台公共语义模型上

How to specifiy enumeration literal as default value in UML Attribute?

由 只愿长相守 提交于 2020-01-14 03:28:07
问题 I currently doing some model transformations using EMF-UML-Implementation. In my model transformation I create an uml class with some attributes. The attributes are type of enumerations I also created. Some of the attribute should get a default value. The default value should be enumeration literals. The question now is, how do I get the enumeration literals to the defaultValue -property of the Property . I already have found that I have to use ValueSpecification . But the UML superstructure

JPA static metamodel with @MappedSuperclass (with a bit of Generation Gap Pattern)

由 不问归期 提交于 2020-01-03 21:03:11
问题 I tried to achieve Generation Gap Pattern with JPA entities. Here is the solution we choose ( <-- are inheritance) BaseEntity <-- EntityGenerated <-- Entity The EntityGenerated type is abstract and mapped with @MappedSuperclass, all field are generated with correct mapping annotation, relation point to the concrete subclass, not the Generated one. The Entity is a concrete type, generated only if the class doesn't exist, initially there is just the class declaration annotated with @Entity.

JPA static metamodel with @MappedSuperclass (with a bit of Generation Gap Pattern)

由 喜夏-厌秋 提交于 2020-01-03 21:02:21
问题 I tried to achieve Generation Gap Pattern with JPA entities. Here is the solution we choose ( <-- are inheritance) BaseEntity <-- EntityGenerated <-- Entity The EntityGenerated type is abstract and mapped with @MappedSuperclass, all field are generated with correct mapping annotation, relation point to the concrete subclass, not the Generated one. The Entity is a concrete type, generated only if the class doesn't exist, initially there is just the class declaration annotated with @Entity.

UML metamodel: derived, derived union and subsetting

由 随声附和 提交于 2020-01-03 08:29:09
问题 If you have ever worked with the metamodel of UML, you propably know the concepts of unions and subsets - As far as I understand it: Attributes and associations of an element/class marked as " derived union " cannot be used directly. In more specific sub-classes, you can possibly find subsets of them that can be used, as long as they are not marked as derived unions themselves. " derived " (without union) attributes and associations have also subsets in more specific classes, but unlike above

JPA Criteria API: LEFT JOIN for optional relationships

由 天涯浪子 提交于 2019-12-21 03:59:08
问题 I'm using the Criteria API basically the first time. It's about abstracting queries for a generic builder: public TypedQuery<T> newQuery( Manager<?,T> manager ) { CriteriaBuilder builder = this.entityManager.getCriteriaBuilder(); Class<T> genericClass = ( Class<T> ) ( ( ParameterizedType ) manager.getClass().getGenericSuperclass() ).getActualTypeArguments()[1]; CriteriaQuery<T> criteriaQuery = builder.createQuery( genericClass ); Root<T> root = criteriaQuery.from( genericClass ); ... } The

JPA/Metamodel: Strange (inconsistent ?) example in Sun Docs

由 寵の児 提交于 2019-12-19 13:48:13
问题 In Sun Online resources, they provide son example about the usage of the Criteria/Metamodel API, but as far as I understand Java, it seems to be impossible to work: CriteriaQuery<Pet> cq = cb.createQuery(Pet.class); Metamodel m = em.getMetamodel(); EntityType<Pet> Pet_ = m.entity(Pet.class); EntityType<Owner> Owner_ = m.entity(Owner.class); Root<Pet> pet = cq.from(Pet.class); Join<Owner, Address> address = cq.join(**Pet_.owners**).join(**Owner_.addresses**); Pet_ is a instance of class

Get model's fields in Django

由 无人久伴 提交于 2019-12-17 03:51:54
问题 Given a Django model, I'm trying to list all of its fields. I've seen some examples of doing this using the _meta model attribute, but doesn't the underscore in front of meta indicate that the _meta attribute is a private attribute and shouldn't be accessed directly? ... Because, for example, the layout of _meta could change in the future and not be a stable API? Is _meta an exception to this rule? Is it stable and ready to use or is it considered bad practice to access it? Or is there a
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