企业工资管理系统的设计与实现外文翻译.doc

1、Powerdesigner的起步与数据建模1、数据建模与PowerDesigner数据模型是信息的一种表示方法和生产消费系统。数据建模包括分析的数据实体系统中存在的关系。PowerDesigner提供概念,逻辑,和物理数据模型来让你你的系统分析和模型各级抽象概念。1.1概念数据模型,一个概念数据模型(CDM)代表逻辑结构,数据系统独立于任何软件或数据存储结构。它给的形式表示数据,需要运行企业、经营活动,可能包含数据对象尚未实施在物质数据库。一个清洁发展机制可以让您:代表组织的数据,在一个图形格式创造的实体关系图表数据设计的有效性进行了验证。产生一个逻辑数据模型(LDM),物理数据模型(PDM)

2、,或一个面向对象模型(OOM指定一个对象),表示清洁发展机制使用UML标准。1.2逻辑数据模型一个逻辑数据模型可以帮助你设计一个数据库结构和执行一些数据库denormalization独立于任何特定的数据库管理系统行为物理的要求。你可以用逻辑模型作为一种中介步骤进行了对比与数据库设计的概念和物理结构:在一开始CDM含有实体,属性,关系、领域、数据项目和业务规则。如果需要的话,你可能会显露出清洁发展机制在几个设计步骤从高水平较低水平的模型,清洁发展机制。产生LDM。FK和指定创建索引列名称和其他共同特点生成一个或更多的(PDMs),每一个为特定的数据库实施这个设计过程使每件东西都保持一致允许你在

3、一个大发展的努力。1.3的物理数据模型物理数据模型(PDM)是一个数据库设计工具的实施适合建模和数据查询生理结构在数据库中。如图1所示。根据数据库的选型你想设计时,你会用不同类型的PDM图。操作PDM你使用的结构设计产品具有可操作性的数据库。一般情况下,在数据建模,物理分析遵循概念和/或逻辑分析,并提出了具体的实际实施数据库中的数据,能满足你的表现和物理限制。商业智能产品数据管理的,你也可以用产品设计了数据库的结构环境,包括:数据仓库或数据集市数据库操作传输数据,从运算数据库,和聚拢所有可能需要的信息的查询资料库,在OLAP(在线分析处理)商业分析和决策执行。数据仓库数据库收集所有的数据处理的

4、公司的例子,而数据集市关注小实体的公司。你使用物理的图表来设计数据仓库和数据集市的数据库。由于这些数据库通常包含了大量的数据存储时,你就不需要设计业绩。你可以指定类型(事实和尺寸)数据库表格有预习多维结构的OLAP(在线分析处理)数据库。多维的OLAP(在线分析处理)数据服务器-通常是封装了数据最先被聚集在数据仓库和数据集市(虽然有时是直接从操作数据库)转移,促进组织的信息查询进行不同的工具。商业分析师使用的OLAP(在线分析处理)数据库发送查询和检索商务信息中存在的不同维度的数据库。你用PDM多维的图表来设计不同的维度和正方体OLAP(在线分析处理)内的数据库。2、创建一个数据模型你可以创建

5、一个新的CDM从头开始,通过引入一个过程分析模型(.PAM),或一个欧文模型(.ERX),或者从产生清洁发展机制、PDM、或OOM。你可以创建一个新的PDM从头开始,或逆向模型从现有的数据库。创建一个新的CDM、LDM或产品数据管理1.选择“文件新开设新对话框。2.选择下列模型类型:概念数据模型逻辑数据模型物理数据模型3.选择下列单选按钮:新模式创建一个新的,空虚,模型。新模型模板-制造模型从他的模型模板,可容纳偏好,扩展选项,预使,对象。更多信息,见”模型模板”一章模式的核心特性的向导。4.进入一个模型的名字。代码的模型,该模型用于剧本或代码生成,是源自这个名字根据模型的命名协定。5 .PD

6、M只有选择数据库管理系统,并说明是否:分享的数据库系统的线条,使用源的数据库管理系统的文件在源文件 DBMS”目录。改变,以适应的数据库系统,能引起所有PDMs分享它。复制数据库定义复印一份模式的数据库系统文件。抄袭的数据库管理系统的产品一起保存更改它不会影响其他(PDMs)。6.PDM只有选择类型的第一个图。图表选择成为默认为下次你创建一个新的产品数据管理。您可以创建许多图,作为您所需要的在CDM、LDM或产品数据管理。7.(可选的)点击扩展模型定义表格,和选择一个或多个定义扩展模型在您的模型。8.单击OK,创造出新的数据模型在当前的工作空间。3、连接数据库要建立或更改PowerBuilde

7、r中数据库连接，使用数据库配置文件。您可以选择为您要访问数据库中的数据库配置文件对话框中的数据库配置文件。使用数据库画家选择一个数据库配置文件，您也可以选择数据库的数据库配置文件您要访问，从数据库画家的对象的视图。但是，此方法使用比使用数据库配置文件对话框中更多的系统资源。 选择数据库配置文件，您可以选择从数据库配置文件对话框数据库配置文件。要连接到一个数据库使用数据库配置文件对话框：1单击数据库档案中的专用PowerBar按钮。或选择工具“数据库的专用PowerBar剖面。数据库Profile按钮 如果您的专用PowerBar不包括数据库Profile按钮，使用自定义功能来添加的按钮，专用P

8、owerBar。让数据库专页上的专用PowerBar按钮是有用的，如果你经常切换不同数据库之间的连接。有关自定义工具栏的说明，请参阅用户指南。数据库配置文件对话框显示，列出已安装的数据库接口。如果接口列表来自当您运行安装程序，它会更新注册表中的供应商名单与你安装的接口。数据库配置文件对话框显示，在供应商名单出现相同的接口。2单击加号（）到您所使用的接口了。或双击该名称。这份名单展开以显示你的界面的数据库定义的配置文件。3选择的数据库配置文件您要访问的名称，然后点击连接。或显示数据库的配置文件弹出菜单，选择连接。PowerBuilder的连接到指定的数据库并返回到工作区的画家。附加说明：以上这篇

9、文献翻译节选自：powerdesigner中的数据建模的有关内容。Powerdesigner Getting Started with Data Modeling1.Data Modeling with PowerDesignerA data model is a representation of the information consumed and produced by a system. Data modeling involves analyzing the data objects present in a system and the relationships betwee

10、n them. PowerDesigner provides conceptual, logical, and physical data models to allow you to analyze and model your system at all levels of abstraction.1.1 Conceptual Data ModelsA Conceptual Data Model (CDM) represents the logical structure of a data system independent of any software or data storag

11、e structure. It gives a formal representation of the data needed to run an enterprise or a business activity, and may contain data objects not yet implemented in a physical database.A CDM allows you to: Represent the organization of data in a graphic format to create EntityRelationship Diagrams Veri

12、fy the validity of data design. Generate a Logical Data Model (LDM), a Physical Data Model (PDM) or an Object-Oriented Model (OOM), which specifies an object representation of the CDM using the UML standard.1.2 Logical Data ModelsA Logical Data Model helps you design a database structure and perform

13、 some database denormalization actions independent of any specific DBMS physical requirements.You can use a logical model as an intermediary step in the database design process between the conceptual and physical designs: Start with a CDM containing entities, attributes, relationships, domains, data

14、 items and business rules. If need be, you may develop the CDM in several design steps starting from a high level model to a low level CDM Generate an LDM. Create indexes and specify FK column names and other common features Generate one or more PDMs, each targeted to a specific DBMSimplementationTh

15、is design process allows you to keep everything consistent in a large development effort.1.3 Data ModelsA Physical Data Model (PDM) is a database design tool suitable for modeling the implementation of physical structures and data queries in a database.Depending on the type of database you want to d

16、esign, you will use different types of diagrams in the PDM: Operational PDM - You use PDM to design the structure of an operational database. Usually, in data modeling, the physical analysis follows the conceptual and/or logical analysis, and addresses the details of the actual physical implementati

17、on of data in a database, to suit your performance and physical constraints. Business intelligence PDM - You can use a PDM to design the structure of a data environment, which consists of: Data warehouse or data mart database are populated with data transferred from operational databases, and gather

18、 together all the information that may be needed in an OLAP database, where queries for business analysis and decision making are performed. The data warehouse database gathers all the data manipulated in a company for example, whereas the data mart focuses on smaller entities in the company.You use

19、 physical diagrams to design a data warehouse or data mart database. Since these databases usually contain very large amounts of data for storage, you do not need to design them for performance. You may assign types (fact and dimension) to the database tables to have a preview of the multidimensiona

20、l structure in an OLAP database. A multidimensional OLAP database - which is generally populated with data that has first been aggregated in a data warehouse or data mart (though sometimes it is transferred directly from operational databases), and in which information is organized to facilitate que

21、riesperformed by different tools. Business analysts use OLAP databases to send queries and retrieve business information from the different dimensions existing in the database.You use PDM multidimensional diagrams to design the different dimensions and cubes within the OLAP database.2.Creating a Dat

22、a ModelYou can create a new CDM from scratch, by importing a Process Analyst Model (.PAM) or an ERwin model (.ERX), or by generating it from a CDM, PDM, or OOM.You can create a new PDM from scratch, or reverse engineer the model from an existing database. To create a new CDM, LDM, or PDM1. Select Fi

23、le New to open the New dialog box.2. Select one of the following model types: Conceptual Data Model Logical Data Model Physical Data Model3. Select one of the following radio buttons: New model Creates a new, empty, model. New model from template Creates a model from a model template, which can cont

24、ain pre-configured options, preferences, extensions, and objects. For more information, see “Model Templates” in the Models chapter of the Core Features Guide .4. Enter a model name. The code of the model, which is used for script or code generation, is derived from this name according to the model

25、naming conventions.5. PDM only Select a DBMS, and specify whether to: Share the DBMS definition use the original DBMS file in the “Resource FilesDBMS” directory. Changes made to the DBMS are shared by all PDMs that share it. Copy the DBMS definition in model make a copy of the DBMS file.The copied D

26、BMS is saved with the PDM and changes made to it do not impact any other PDMs.6. PDM only Select the type of the first diagram. The diagram chosen becomes the default for the next time you create a new PDM. You can create as many diagrams as you need in a CDM, LDM, or PDM.7. optional Click the Exten

27、ded Model Definitions tab, and select one or more extended model definitions to attach to your model.8. Click OK to create the new data model in the current Workspace.3.Connecting to a databaseTo establish or change a database connection in PowerBuilder, use a database profile. You can select the da

28、tabase profile for the database you want to access in the Database Profiles dialog box.Using the Database painter to select a database profileYou can also select the database profile for the database you want to accessfrom the Database painters Objects view. However, this method uses more system res

29、ources than using the Database Profile dialog box.Selecting a database profileYou can select a database profile from the Database Profiles dialog box.To connect to a database using the Database Profiles dialog box:1Click the Database Profile button in the PowerBar.orSelect ToolsDatabase Profile from

30、 the PowerBar.Database Profile buttonIf your PowerBar does not include the Database Profile button, use thecustomize feature to add the button to the PowerBar. Having the Database Profile button on your PowerBar is useful if you frequently switch connections between different databases. For instruct

31、ions on customizing toolbars, see the Users Guide.The Database Profiles dialog box displays, listing your installed database interfaces.Where the interface list comes fromWhen you run the Setup program, it updates the Vendors list in the registrywith the interfaces you install. The Database Profiles

32、 dialog box displays the same interfaces that appear in the Vendors list.2Click the plus sign (+) to the left of the interface you are using.orDouble-click the name.The list expands to display the database profiles defined for your interface.3Select the name of the database profile you want to access and clickConnect.orDisplay the pop-up menu for a database profile and select Connect.PowerBuilder connects to the specified database and returns you to the painter workspace.From: Sybase PowerDesigner. .此处忽略！