【正文】 感謝出版?zhèn)鞑ヅc管理學(xué)院的領(lǐng)導(dǎo)對我的悉心栽培，也感謝信管專業(yè)教研室的其他老師們對我的幫助。維護(hù)的費(fèi)用和初期的研制費(fèi)用差不多，甚至更高。本系統(tǒng)包括兩個(gè)程序、若干臺設(shè)備和大量的數(shù)據(jù)結(jié)構(gòu)。 我們的貨單系統(tǒng)有二個(gè)程序，一個(gè)事務(wù)處理，直接存取貨單文件似乎是個(gè)合適的方案；另一個(gè)為經(jīng)營部門偶爾分析貨物清單數(shù)據(jù)用，當(dāng)然批處理就能完成了。 如何組織文件呢？這取決于如何訪問它。最后，貨物清單文件由一個(gè) Report and reorder（報(bào)告和訂貨）程序處理。最終，這些有用的工具為下一步設(shè)計(jì)階段，奠定了一個(gè)良好的基礎(chǔ)。因?yàn)橄到y(tǒng)是由用戶提出的，所以首先要確定用戶的需求。數(shù)據(jù)從 STOCK 流入 Generate reorder,因此商品說明和訂貨數(shù)量必定存放在 STOCK 中。 STOCK 保存貨單中每項(xiàng)商品的數(shù)據(jù)．為了對新的事務(wù)處理起作用，事務(wù)處理程序要改變數(shù)據(jù)。 11 圖 1 已知了系統(tǒng)的基本功能，分析員的下一個(gè)任務(wù)是分析理解這些功能之間邏輯關(guān)系的知識。 分析 分析開始時(shí)，分析員要理解問題， 下一步要決定的是為了解決問題必須做什么。在該階段上，分析員不必考慮程序、文件或計(jì)算機(jī)硬件，但他們必須用自己的專業(yè)術(shù)語與用戶對話。一方面庫存太多會(huì)造成不必要的開銷；另一方面可供挑選的商品太少會(huì)使顧客失去購買的信心。麻煩的是。例如，考慮一個(gè)工資系統(tǒng)，它的目標(biāo)是為雇員付工資，應(yīng)包含哪幾部分呢？每天雇員們把他們工作的時(shí)數(shù)記錄在計(jì)時(shí)卡片上，每周末把計(jì)時(shí)卡片收集起來，送給計(jì)算中心，在計(jì)算中心把計(jì)時(shí)卡片上的數(shù)據(jù)讀給工資程序。s when the air defense program is run is absurd. Instead, because of the need for quick response, each transaction must be processed as it occurs. Generally such transaction processing systems call for direct access file. Our inventory system has two programs. One processes transactions. A direct access inventory file seems a reasonable choice. The other allows management to study inventory data occasionally。 instead, we want to identify, at a black box level, necessary programs, files, procedures, and other ponents. The data flow diagram defines the system39。s memory. 4 Finally, data flow between sources, destinations, processes, end data stores over data flows, which are represented by arrows. Fig 2 Figure 2 shows a preliminary data flow diagram for the inventory system. Start with CUSTOMER. Transactions flow from a customer f into the system, where they are handled by Process transaction. A data store, STOCK, holds data on each item in inventory. Process transaction changes the data to reflect the new transaction. Meanwhile, MANAGEMENT accesses the system through Communicate, evaluating the data in STOCK and, if necessary, requesting a reorder. Once, a reorder is authorized. Generate reorder sends necessary data to the SUPPLIER, who ships the items to the store. Note that, because the reorder represents a change in the inventory level of a particular product or products it is handled as a transaction. The data flow diagram describes the logical system. The next step is tracing the data flows. Start with the destination SUPPLIER. Reorders flow to suppliers。s understanding of the problem is essential. The user should review and correct this written statement. The time to catch misunderstandings and oversights is now, before time, money and effort are wasted. Often, following a preliminary problem definition, the analyst performs a feasibility study. The study a brief capsule version of the entire systems analysis and design process, attempts to answer three questions: the problem be solved? it be salved in the user39。I 附錄 1 外文翻譯 (原文 ) Systems Analysis and Design Working under control of a stored program, a puter processes data into information. Think about that definition for a minute. Any given puter application involves at least three ponents: hardware, software, and data. Merely writing a program isn39。s environment? it be solved at a reasonable cost? If the answer to any one of these questions is no, the system should not be developed. Given a good problem definition and a positive feasibility study, the 3 analyst can turn to planning and developing a problem solution. 2 2 Analysis As analysis begins, the analyst understands the problem. The next step is determining what must be done to solve it. The user knows what must be done 1 during analysis。 for example, the store might want 25 pairs of jeans. To fill the order, the supplier needs the product description and the reorder quantity. Where do these data elements e from? Since they are output by Generate reorder, they must either be Input to or generated by this process. Data flow into Generate reorder for STOCK。s necessary functions。 batch processing would certainly do. Should the inventory file be anized sequentially or directly? Faced with s uch a choice a good analyst considers both options. One possible system might accept transactions and process them as they occur. As an alter