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Point of Sale System

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TABLE OF CONTENTS OBJECTIVE 2

Situation 2 Intended users, expectations and features facilitating the job 2

ANALYSIS 4 Different relational database management systems 4 Different ways of transmitting information 5 Requirements of the server 6 Choice of IT tools 6

DESIGN 8 Entity-Relationship Diagram 8 Tables and attributes in the database 9 Network diagram 11 Specification and explanation of the network design 12

IMPLEMENTATION 13 Creating tables in the database 13 Creating relationships between tables 14 Inputting data for testing purpose 14 Data verification and validation 15 Creating views 16 Output features 18 Sample user interface (using Microsoft Visual Basic) 19

TESTING AND EVALUATION 20 Testing of views 20 Other things to test 24

CONCLUSION AND DISCUSSION 25 REFERENCES 26 Source Codes Appendix I Guidelines on how to attach the database to MS SQL Server Appendix II

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OBJECTIVE

Situation A book shop has 4 branches in different regions in Hong Kong. The owner has

employed workers to run the shop, for example, cashiers, people who manage the inventories and some staff who answer customers’ question and help them to get the books they want. Every weekend, after the business hours, all of them have to stay and count the number of books sold and profits they earned that week, and then write the records on the sheets designed and given by the main branch. On the last day of each month, the manager of each branch has to send the forms to the main shop. Everything is done manually.

The owner has received feedbacks from employees, saying that there is too much workload because they have to be very careful so that they will not be making any mistakes in recording of the goods sold and the revenue. Some people also complained that when they come to the book stores asking for a book, the staff has to spend a lot of time searching for it.

In addition, if the owner wants to extend his business, he could not continue to rely on the workers to do the work manually.

Intended users, expectations and features facilitating the job

1. Business administration

Users want to have information such as the sales revenue of each branch and which kind of book is the most popular among customers. They need these kinds of information to plan promotions for the store.

Features: The database will provide data on the statistics they need. 2. Membership administration

The owner plans to develop a member system and give discounts to members according to how long they have been a member.

Features: The database will have a table containing members’ information. 3. Inventory control

Shopkeepers want to have an organized way in accessing the information of the books easily. Besides, they want to know the quantity of the books in stock with the new system so that they can order books from publishers effectively.

Features: The database will contain information for the books and inventory.

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Besides, when a transaction is made, the quantity left will be changed automatically. Publishers’ information will also be stored in the database. 4. Financial control

The owner wants to have information on how profitable his business is. Features: The database will provide information on the cost and revenue of the

book store. 5. Others

Cashiers suggest a bar code scanner be added to facilitate transactions so that they can get the price of the book quickly.

Features: After adding the bar code scanner, the database can use the ISBN of the book to obtain information of the book.

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ANALYSIS

Different relational database management systems

Characteristics

Oracle 10g Microsoft SQL Server 2005

PostgreSQL MySQL

Maintainer Oracle Corporation Microsoft PostgreSQL Global Development Group

MySQL AB

Operating systems support

Windows/ Mac OS X/ Linus/ UNIX/ z/OS

Windows Windows/ Mac OS X/ Linus/ BSD/ UNIX

Windows/ Mac OS X/ Linus/ BSD/ UNIX

Fully Relational - affects data storage, retrieval and integrity

Yes Yes Yes does not support foreign key constraints

Language PL/SQL - considered more powerful than Transact-SQL but more difficult to use

Transact-SQL - considered easy to use and more powerful than MySQL Dialect

PL/pgSQL - resembles Oracle's procedural language PL/SQL.

MySQL Dialect - difficult to use with limited power

Open Source No No Yes Yes

Maintainability Difficult Easy Difficult Difficult

Reliability High High Medium Medium

Application support ODBC, JDBC, ADO.Net, OLEDB, etc.

ODBC, JDBC, ADO.Net, etc. (Microsoft Visual Studio to provide end-to-end application development capabilities)

ODBC, JDBC, C/C++, Embeded SQL (in C), Tcl/Tk, Perl, Python, PHP

ODBC, JDBC, C/C++, .NET/Mono, ADO.Net, OLEDB, Delphi, Perl, Python, PHP, etc.

Pricing

Oracle 10g Microsoft SQL Server 2005 Standard Standard Edition $15,000 Standard Edition $5,999

Total Cost $15,000 $5,999

Enterprise Edition $40,000 Enterprise Edition $24,999

Management Packs $6,000 Management Tools Included

Advanced Security $10,000 Network Encryption, Single sign-on, PKI

Included

Enterprise

Business Intelligence (OLAP and BI add-on)

$40,000 Integration, Reporting and Analysis services

Included

Subtotal $96,000 $24,999

High availability

Additional database instance for high availability

$96,000 Additional database instance Included

Subtotal $192,000 $24,999

Multicore Cost of additional core (dual-core processor)

$192,000 Cost of additional core Included

Total Enterprise Cost

$384,000 $24,999

* PostgreSQL and MySQL are free open-source database software.

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Different ways of transmitting information

Intranet (Dedicated Leased Line Connection)

An intranet is a private computer network that uses Internet protocols, network connectivity, and public telecommunication system so that people can share information and operations within an organization. The Intranet environment is completely owned by the organization and is generally not accessible from the Internet. Clients and servers running on the Internet protocol suite are used to build an intranet. HTTP and other Internet protocols are commonly used as well, especially FTP and e-mail.

Intranets can help employees to find and view information and applications quickly, according to their roles so that they can finish their job quickly and accurately. It can also support business operations and decisions across the inter-networked enterprise.

It also has some disadvantages, for example, there would be some security concerns with who has the right to access certain information in the intranet, besides, it could be difficult for the managers to control materials provided by the intranet.

However, to set up a Wire Area Network for an intranet is very expensive, which is not suitable for this small book store. Internet (Virtual Private Network)

The internet is the worldwide, publicly accessible network of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol. It is a network containing a lot of networks from all over the world, for example, academic, business, domestic networks, etc. The functions provided by the internet include email, instant messaging, file transferring, web browsing, etc.

Its function is similar to that of intranet but the major difference is that the internet is almost opened to everyone who has internet connection. Thus, this is also a disadvantage if the company stores its information using the internet server because people outside the company may get into the server and disclose the information.

To use the internet for data communication in a more secure way for the book store, a virtual private network may help.

A VPN is a private network that uses a public network (usually the Internet) to connect remote sites or users together. Instead of using a dedicated, real-world connection such as a leased line, a VPN uses "virtual" connections routed through the Internet from a private network to a remote site. It provides users with secure access to their own network. In practice, by encrypting data at the sending end and decrypting it at the receiving end, it prevents data from being altered during transmission, maintaining data integrity and security. In addition, it also encrypts the

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address of the originating and receiving network to ensure that only authorized users can access the network.

VPN server software should be installed in the LAN with a VPN connection. The remote users in other branches need to install a VPN client software.

Requirements of the server Operating system:

Network Operating System which manages the network and entertains requests from clients. Processors:

Use multiple processors so that the speed of processing can be increased. RAM:

Use larger and more reliable RAM so that the server can perform better. Fault-tolerant Features:

1. RAID System Improve the speed of the server and prevent data loss in case of disk failure.

2. UPS It provides temporary power supply to the computer when the mains fails.

3. Backup Server It holds an updated copy of the important information of the store.

Choice of IT tools

Database – Microsoft SQL Server 2005

The main reason for choosing MS SQL Server is its graphical user interface which is more user friendly. Since most of the staff are more familiar with Microsoft Windows, the time required to train them for this new system would be shorter.

Other languages are more difficult to learn, the staff in the store may not be able to handle the problems. The cost of employing technicians is also higher.

Moreover, Oracle requires a much higher cost in purchasing a whole set of its enterprise edition. It is not suitable for a small book store which has just started to develop a new POS system.

Another extra advantage is that SQL Server has a tight integration with Microsoft Office products like Word, Excel which are very commonly used in the companies nowadays.

The following is a list of features of Microsoft SQL Server 2005. Rich XML Support: Simplify the integration of the back-end systems and

data transfer across firewalls using XML.

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Integration with Windows Server System—BizTalk Server and Commerce Server: SQL Server 2005, in conjunction with other Microsoft Windows Server System™ integrated server software, provides even more power for e-business.

Security: Ensure applications to be secure in any networked environment, with role-based security and file and network encryption.

Full-Text Search: Use and manage both structured and unstructured data, including searching through Microsoft Office documents.

High Availability: Maximize the availability of business applications with log shipping, online backups, and failover clusters.

Scalability: Scale the applications up to 32 CPUs and 64 gigabytes (GB) of RAM.

Indexed Views: Gain performance from the existing hardware by storing query results and reducing response times.

Simplified Database Administration: Automatic tuning and maintenance features enable administrators to focus on other critical tasks.

Improved Developer Productivity: User-defined functions, cascading referential integrity, and the integrated Transact-SQL debugger allow the reuse of code to simplify the development process.

English Query: Enable users to pose questions in English instead of using multi dimensional expressions (MDX).

Connection Links – Virtual Private Network

Since private leased lines are very expensive and is usually used by larger organizations, VPN should be used. It can also perform security measures such as encryption, authentications and prevent message alteration.

This technology is widely used today because it allows users to access "intranet" in a different geographical location.

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DESIGN

Entity-Relationship Diagram

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Tables and attributes in the database

BOOK – Storing information of the books

Attribute Name Type Example

ISBN char(13) 0141030089

Bk_Title char(150) Freakonomics (Revised Edition)

Bk_Author char(50) Steven D. Levitt, Stephen J. Dubner

Bk_Price money 96.0000

Pub_ID smallint 10

Bk_Category char(20) Political Science

INVENTORY – Recording how many books are left in each store

Attribute Name Type Example

Sto_ID tinyint 1

ISBN char(13) 0141030089

Bk_Qty numeric(18,0) 40

MEMBER – Storing information of members

Attribute Name Type Example

Mem_ID int 100

Mem_Name char(25) Hilda Chan

Mem_Sex char(1) F

Mem_DOB datetime 01/02/1988 00:00:00

Mem_Tel char(8) 23545654

Mem_Address char(80) Flat B, 1/F, 2 Sun Street, Hong Kong

Mem_DOApplication datetime 03/09/2006 00:00:00

ORDER – Recording the ordering of books from the publishers

Attribute Name Type Example

Order_ID int 1000

Order_Date datetime 01/10/2006 00:00:00

ISBN char(13) 0141014253

Sto_ID tinyint 3

Order_Qty int 40

PUBLISHER – Storing information of the publishers

Attribute Name Type Example

Pub_ID smallint 1

Pub_Name char(25) FormAsiaBooks

Pub_Tel char(8) 20000001

Pub_Address char(80) 1 Amoy Street, Mongkok, Kowloon

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STAFF – Storing information of the employees

Attribute Name Type Example

Sta_ID smallint 10

Sta_Name char(25) Ada Chan

Sta_Sex char(1) F

Sta_DOB datetime 28/7/1980 00:00:00

Sta_Tel char(8) 21521521

Sta_Address char(80) Flat A, 10/F, 1 Hoi King Road, Kowloon

Sta_Salary money 6000.0000

Sto_ID tinyint 1

STORE – Storing the telephone number and address of each branch

Attribute Name Type Example

Sto_ID tinyint 1

Sto_Tel char(8) 21000001

Sto_Address char(80) 4 Lock Road, Tsim Sha Tsui, Kowloon

TRANSACTION – Records of all the transactions

Attribute Name Type Example

T_ID int 110011

T_DateTime datetime 02/09/2006 11:35:56

Sto_ID tinyint 1

ISBN char(13) 0006471250

T_Qty int 1

Mem_ID int NULL

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Network diagram

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Specification and explanation of the network design In each store, CAT5 UTP cables will be used to connect all the devices because

the cost is lower and it can be easily installed. Wireless connection is not chosen because of its higher cost. In addition, fiber-optic cable is not used because it is more suitable for building a network backbone but not in a LAN.

Switches are used instead of hubs because hub creates data collision easily and it has the bandwidth will be smaller because it uses broadcasts.

Printers connected to each cashier are for printing receipts. A laser printer is connected to one of the workstations in the management department for printing documents, etc.

Every branch will connect to Shop 1 through using VPN connection. Virtual private networks can be a cost-effective and secure way for different companies to provide users access to the company’s network and for remote networks to communicate with each other across the Internet. VPN connections are more cost-effective than dedicated private lines; usually a VPN involves two parts: the protected or "inside" network, which provides physical and administrative security to protect the transmission; and a less trustworthy, "outside" network or segment (usually through the Internet). Therefore, the network in shop 1 will be the "inside" network and the networks in shops 2, 3 and 4 will be those "outside" networks.

In case the internet connection fails and the other branches cannot communicate with the server in shop 1, the server in shops 2, 3 and 4 should store a copy of the data. This is done manually by one of the shop assistants every week.

A full backup performs every Sunday at 3a.m., an incremental backup performs every day except on Sunday at 3a.m. Files will be stored in the server of Shop 1’s management department.

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IMPLEMENTATION

Creating tables in the database

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Creating relationships between tables

Inputting data for testing purpose

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Data verification and validation

The above picture shows that day cannot exceed 31 in October.

This picture shows that the column ISBN does not allow NULL values since this property is set when the table is created.

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In the prototype, my focus is on the "Business administration" function. Therefore, I have created some views to show the performance of the book store. View name Description

BookSales_2006 Shows the number of copies sold for each book in year 2006

CategorySales_2006_09 Shows the number of books sold for each category in September 2006

CategorySales_2006_10 Shows the number of books sold for each category in October 2006

SalesRevenue Shows the total sales revenue in each month for all the stores

SalesRevenue_Store1 Shows the total sales revenue in each month for Store 1

SalesRevenue_Store2 Shows the total sales revenue in each month for Store 2

SalesRevenue_Store3 Shows the total sales revenue in each month for Store 3

SalesRevenue_Store4 Shows the total sales revenue in each month for Store 4

StaffList Shows the whole list of staff

Creating views

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Output features

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Sample user interface (using Microsoft Visual Basic)

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TESTING AND EVALUATION

Testing of views

1. Showing the number of copies sold for each book in year 2006

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2. Showing the number of books sold for each category in September 2006

3. Showing the number of books sold for each category in October 2006

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4. Showing the total sales revenue in each month for all the stores

5. Showing the total sales revenue in each month for Store 1

6. Showing the total sales revenue in each month for Store 2

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7. Showing the total sales revenue in each month for Store 3

8. Showing the total sales revenue in each month for Store 4

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9. Showing the whole list of staff in ascending order of their ages

The above views successfully show the necessary data for the business administration department, including sales revenue of each branch, which book and which kind of book is the most popular among customers, etc.

Other things to test Check the cables using cable tester Check if the servers are working properly with an acceptable speed of

responding clients’ requests Check if the workstations in other stores can connect to the VPN server Check if the clients can use the services provided by the server Check if the backups are performing at the scheduled time and whether the data

can be restored successfully with the backup files

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CONCLUSION AND DISCUSSION

Generally speaking, the system meets the requirements of users mentioned in the "Objective" section of the report. However, there are also shortcomings of the system.

Firstly, some views have to be created by the users manually for another month or another year, such as the views for the number of books sold in a year, the number of the books in a category sold in a particular month. Also, there will be a lot of views after a period of time.

Secondly, the system has not yet implemented features like granting discounts to members because the focus in the prototype is not on the membership administration. Therefore, the total revenue shown in the views are over-estimated.

Thirdly, it is better to employ programmers to design a graphical user interface for the users so that they do not need to enter SQL command themselves.

One of the reasons for my slow process in this project is that I do not understand

how much I have to do for the prototype. At the beginning, I thought that I have to create a graphical user interface that can facilitate the work of the staff and it makes me hesitate to start doing it.

Moreover, it is very difficult to start writing the project without adequate knowledge and experience on networking. This is because the project requires students to analyze different connection methods and network designs.

Microsoft SQL Server is a very user-friendly tool. It provides a very convenient

user interface. It does not require user to input SQL commands when creating tables, inserting data or creating views. Theoretically, it is better to choose a database management system which can be used on Linux environment because experienced users will find that Linux is more stable. However, Microsoft’s products are famous for their easiness to use. Therefore, it suits users who do not have enough experiences in using database software. In the book shop’s situation, if the owner wish to do a small-sized business and does not want to employ too many technicians, Microsoft SQL Server should be a good choice of database development tool.

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