📚 Case Study Practical Exercise for SQA Computing | SQA 计算机案例分析实战演练
This article takes you through a complete case study for the SQA National 5 / Higher Computing Science course, applying the software development process to a real‑world scenario. We will analyse requirements, design a solution, implement key components, test functionality, and evaluate the outcome. The aim is to build confidence in tackling SQA practical tasks and written exam questions that ask you to “describe”, “explain” or “justify” decisions in a development context.
本文将带领你完成 SQA 国家五级 / 高级计算机科学课程的一个完整案例分析，将软件开发流程应用于一个真实场景。我们将分析需求、设计解决方案、实现关键组件、测试功能并评估结果，旨在帮助你建立信心，从容应对 SQA 实践任务和书面考题中要求你“描述”、“解释”或“论证”开发决策的问题。
1. The Scenario – School Library System | 场景——学校图书馆系统
Our case study is a small library management system for a secondary school. The librarian needs to track books, borrowers (pupils and staff), loans and returns. The current paper‑based system is slow and error‑prone. The school wants a digital solution that runs on the library PC, with future possibility of a web interface.
我们的案例是一个针对中学的小型图书馆管理系统。图书管理员需要追踪图书、借阅者（学生和教职员工）、借出和归还。目前基于纸质的系统效率低且容易出错。学校希望开发一个在图书馆电脑上运行的数字解决方案，未来可能扩展为网页界面。
2. Analysis – Identifying Requirements | 分析——明确需求
During analysis we interview the librarian and examine the paper records. We identify three types of user: librarian (full access), pupil (search & reserve), teacher (extended loan period). Functional requirements include: add/remove books, register borrowers, loan a book, return a book, search by title/author, and generate overdue reports.
在分析阶段，我们访谈了图书管理员并检查了纸质记录。我们识别出三类用户：图书管理员（完全访问权限）、学生（搜索和预约）、教师（延长借阅期）。功能性需求包括：添加/删除图书、注册借阅者、借出图书、归还图书、按书名/作者搜索以及生成逾期报告。
Non‑functional requirements include response time under 2 seconds for searches, password protection for librarian functions, and data backup every evening. We document these in a software specification agreed with the school.
非功能性需求包括搜索响应时间低于两秒、对图书管理员功能的口令保护以及每晚数据备份。我们将这些记录在与学校达成一致的软件规格说明书中。
3. Design – Interface & Structure | 设计——界面与结构
We design a graphical user interface using wireframes. The main menu has buttons: Manage Books, Manage Borrowers, Issue Loan, Return Book, Search, Reports. Each opens a form.
我们使用线框图设计了图形用户界面。主菜单包含按钮：管理图书、管理借阅者、办理借出、归还图书、搜索、报告。每个按钮打开一个表单。
We plan to use a modular structure with procedures/functions for each major task. The data will be stored in external sequential files (CSV) to keep the solution simple for the single‑user environment. We also design a data dictionary:
我们计划采用模块化结构，每个主要任务对应一个过程/函数。数据将存储在外部顺序文件（CSV）中，以保持单用户环境下方案的简洁性。我们还设计了数据字典：
| Field | Type | Description |
|---|---|---|
| bookID | String (6) | Unique book code |
| title | String (50) | Title of the book |
| author | String (30) | Author surname |
| borrowerID | String (8) | Linked to borrower record |
4. Design – Logic & Algorithms | 设计——逻辑与算法
We decide to use pseudocode to plan key algorithms. For example, the loan procedure must check that the borrower has no overdue items, the book is available, and then update the loan file and book status.
我们决定使用伪代码规划关键算法。例如，借书过程必须检查借阅者没有逾期物品、图书是可借状态，然后更新借阅文件和图书状态。
A flowchart or structure diagram could also be used. The searching algorithm will be a linear search through the book file, as the dataset is small (<2000 books). We discuss efficiency and justify our choice.
也可以使用流程图或结构图。搜索算法将采用对图书文件的线性搜索，因为数据集很小（少于 2000 本书）。我们讨论了效率并论证了选择。
5. Implementation – Programming Constructs | 实现——编程结构
We implement the solution in a high‑level language (e.g., Python). We use arrays (lists) to hold records from file. The code uses sequence, selection (IF statements for menu choices and validation) and iteration (FOR loops to read files, WHILE loops for menus).
我们使用高级语言（例如 Python）实现解决方案。我们使用数组（列表）来存放从文件读取的记录。代码运用了顺序结构、选择结构（用于菜单选择和验证的 IF 语句）和迭代结构（FOR 循环读取文件，WHILE 循环处理菜单）。
Below is a snippet for loading the book file:
bookFile = open('books.csv','r')
for line in bookFile:
booklist.append(line.strip().split(','))
bookFile.close()
Data validation is essential: we ensure book ID is not empty, loan period for pupils is 14 days, for teachers 30 days. We use built‑in functions like len() and int() to check inputs.
数据验证至关重要：我们确保图书 ID 不为空，学生借阅期 14 天，教师借阅期 30 天。我们使用 len() 和 int() 等内置函数来检查输入。
6. Testing – Test Plan & Examples | 测试——测试计划与案例
We create a test plan with normal, extreme, and exceptional data. For instance:
- Normal: loan a book to a pupil with no existing loans.
- Extreme: loan the last available copy of a book.
- Exceptional: try to loan a book that does not exist.
我们创建了一个包含正常、极端和异常数据的测试计划。例如：
- 正常：给一个没有现有借阅的学生借出一本书。
- 极端：借出最后一本可借副本。
- 异常：尝试借出一本不存在的书。
We document expected vs actual results and fix any logic errors. A common bug is failing to update the book status after return; this is caught during testing.
我们记录预期结果与实际结果的对比，并修正任何逻辑错误。一个常见错误是归还后未更新图书状态；这会在测试中被发现。
7. Evaluation – Fitness for Purpose | 评估——适用性
We evaluate the solution against the original requirements. All functional requirements are met. The system is easy to use and responses are fast. However, we note that using CSV files might cause problems if multiple users try to access simultaneously; this is acceptable for the current single‑user setup.
我们对照原始需求评估解决方案。所有功能性需求均已满足。系统易于使用且响应迅速。但我们注意到，如果多个用户同时访问，使用 CSV 文件可能引发问题；在当前单用户设置下这是可接受的。
We also evaluate the user interface: the librarian found it intuitive. The maintainability is good because the code is well‑commented and modular. Future enhancements could include a database backend and barcode scanner integration.
我们还评估了用户界面：图书管理员认为界面直观。可维护性良好，因为代码注释清晰且模块化。未来的增强功能可以包括数据库后端和条码扫描器集成。
8. Documentation – User & Technical Guides | 文档——用户指南与技术说明
Part of the SQA assignment expects clear documentation. We produce a user guide with screenshots explaining how to add a book, issue a loan etc. A technical guide includes the data dictionary, pseudocode, and a list of parameters passed between modules.
SQA 作业要求提供清晰的文档。我们编写了带截图的用户指南，解释如何添加图书、办理借阅等。技术指南包括数据字典、伪代码以及模块间传递的参数列表。
Both guides are written in simple language, avoiding jargon. The technical guide is useful for another developer maintaining the system.
两份指南均使用简单语言编写，避免专业术语。技术指南对另一名维护系统的开发者很有帮助。
9. Social & Ethical Considerations | 社会与伦理考量
We consider the impact of storing personal data about borrowers. The system complies with data protection principles: data is collected for specified purposes, kept secure, and not shared. We also consider accessibility: the interface uses large fonts and high contrast for visually impaired users.
我们考虑了存储借阅者个人数据的影响。系统遵守数据保护原则：为特定目的收集数据、确保安全且不共享。我们还考虑了无障碍性：界面使用大字体和高对比度，方便视障用户。
Environmental impact is minimal as the system reduces paper usage. We discuss the digital divide – the school must ensure all learners have equal access to the library system.
环境影响极小，因为系统减少了纸张使用。我们讨论了数字鸿沟——学校必须确保所有学习者都能平等使用图书馆系统。
10. Linking to SQA Assessment Standards | 关联 SQA 评估标准
This case study covers SQA outcomes: analysing a problem, designing, implementing, testing, and evaluating a solution. It also addresses the “understanding of the legal, social, environmental and ethical implications” required for Higher. By working through each stage and documenting decisions, you practise the very skills examined in assignments and question papers.
本案例覆盖了 SQA 的学习成果：分析问题、设计、实现、测试和评估解决方案。它还涉及高级要求中“对法律、社会、环境和伦理影响的理解”。通过逐步实践并记录决策，你锻炼了在作业和试卷中考查的完全相同的能力。
Remember to be precise in explaining “why” you made a choice – that is where high marks are earned.
请记住，在解释“为什么”做出某个选择时要精确——这就是获得高分的关键。
Published by TutorHao | Computing Revision Series | aleveler.com
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