The prevailing distributed computing model of the curent era is called ctiem servarcomputing. A Client/Server system is a solution in which the presentation,presentation logic. application logic,data manipulation and data layers are distributed between client PCs and one or more servers. A Thin client is a personal computer that does not have to be very powerfil in terms of processor speed and memory because it only presents the interface to the user. A Fat client is a personal computer,notebook. computer,or workstation that is typically more powerfil in terms of processor speed,memory,and storage capacity. A Database serverer hosts one or more shamad database but also executes all database commands and services for information systems. An Web server hosts Internet or intranet Web sites,it communicates with clients by returning to them documents and data.
当前流行的分布式计算模型称为ctiem servarcomputing。客户机/服务器系统是一种解决方案，其中表示、表示逻辑。应用逻辑、数据操作和数据层分布在客户端PC和一个或多个服务器之间。瘦客户机是一种个人计算机，在处理器速度和内存方面不一定非常强大，因为它只向用户提供界面。胖客户端是个人电脑、笔记本电脑。在处理器速度、内存和存储容量方面通常更强大的计算机或工作站。数据库服务器托管一个或多个shamad数据库，但也执行信息系统的所有数据库命令和服务。Web服务器托管Internet或intranet网站，它通过向客户返回文档和数据与客户进行通信。
The purpose of systems design is to specify a(n) application architecture , which defines the technologies to be used to build the proposed information systems. This task is accomplished by analyzing the data models and process models that were initially created during requirements analysis. The physical data flow diagram is used to establish physical processes and data stores across a network. To complete this activity, the analyst may involve a number of system designers and system user , which may be involved in this activity to help address business data, process, and location issues. The key inputs to this task are the facts, recommendations, and opinions that are solicited from various sources and the approved system proposal from the decision analysis phase
大意： 系统设计的目的是确定一种应用体系结构，该架构定义了用于构件所建议信息系统的技术。 通过分析最初在需求分析期间创建的数据模型和过程模型来完成该项目任务。物理数据 流程图用于在整个网络上建立物理过程和数据存储。未来完成此活动，分析人员可能需要许多系统设计人员和系统用户参与到该活动中，帮助处理业务数据、流程和位置问题。该任务的关键如数是从各种来源获取的事实、建议和意见，以及在决策分析阶段获批的系统建议。
During the systems analysis phase, you must decide how data will be organized, stored,and managed. A data structure is a framework for organizing, storing, and managing data. Each file or table contains data about people, places, things, or events. One of the potential problems existing in a file processing environment is data redundancy , which means that data common to two or more information systems is stored in several places. In a DBMS, the linked tables form a unified data structure that greatly improves data quality and access. A(n) entity-relationship diagram is a model that shows the logical relationships and interaction among system entities. It provides an overall view of the system and a blueprint for creating the physical data structures. Normalization is the process of creating table designs by assigning specific fields or attributes to each table in the database. A table design specifies the fields and identifies the primary key in a particular table or file. The three normal forms constitute a progression in which third normal form represents the best design. Most business-related databases must be designed in that form.
在系统分析阶段，需要确定数据如何组织、存储和管理。数据结构是用于组织存储和管理数据的一个框架。每个文件或表中包含了关于人物、地点、事物和事件的数据。文件处理场景中存在的潜在问题之一是数据冗余，意味着两个或多个信息系统中相同的数据存储在多个不同位置。 在关系数据库管理系统中， 互相链接的表形成了一个统一的数据结构，可以大大提升数据指令和访问。实体联系图是一个模型，显示了系统实体之间的逻辑关系和交互。它提供了一个系统的全局视图和用于创建物理数据结构的蓝图。规范化是通过为数据库中的每个表分配特定的字段或属性来创建表设计的过程。表设计是在特定表或文件中确定字段并标识主关键字。三种范式构成了一个序列，其中第三范式代表了最好的设计，大部分与业务相关的数据库必须设计成这种形式。
Designing the data storage architecture is an important activity in system
design. There are two main types of data storage formats: files and databases.
Files are electronic of data that have been optimized to perform a particular
transaction. There are several types of files that differ in the way they are
used to support an application. Master files store core information
that is important to the business and , more specifically, to the
application , such as order information or customer mailing information .
Audit files contain static values, such as a list of valid codes or the names of cities .Typically, the list is used for validation. A database is a collection of
groupings of information that are related to each other in some way. There are
many different types of databases that exist on the market today.
Legacy database is given to those databases which are based on
older , sometimes outdated technology that is seldom used to develop new
applications. Hierarchical database are collections of records
that are related to each other through pointers In relational database,
referential integrity can be used in ensuring that values linking the tables together through the primary and foreign keys are valid and correctly synchronized.
设计数据存储架构是系统设计中的一项重要活动。数据存储格式有两种主要
类型：文件和数据库。文件是优化以执行特定交易数据的电了数据。有几种类型的文件在用于支持应用程序的方式上有所不同。主文件存储的核心信息对业务很重要，更具体地说，对应用程序而言，例如订单信息或客户邮件信息。审计文件包含静态值，例如有效代码列表或城市名称。通常，该列表用于验证。数据库是以某种方式彼此相关的信息分组的集合。目前市场上存在许多不同类型的数据库。旧数据库给予那些基于较旧的，有时过时的技术的数据库，这些技术很少用于开发新的应用程序。分层数据库是通过指针彼此相关的记录集合在关系数据库中，参照完整性可用于确保通过主键和外键将表链接在一起的值是有效且正确同步的。