Producing computerized system

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This assignment is to produce the designs for producing computerized system of DVD loan system. DVD store only allows members who registered to borrow DVDs. DVD store include public workstations and remaining workstation. Public workstation is for members to search item availabilities by title, keyword, director or category. Remaining workstation is for staff use only. This includes not only the functions of public workstation but also loan, return and other processes. Members can choose loan period of 24 hour, 48 hour or 1 week with different fees. If overdue, return fee will be paid for every 24 hour period after the due return date. Member cannot loan more than 5 DVDs at any time. Shop assistants will be responsible for member registration and modification, loan and return processes. Manage will be responsible for ordering new DVD and sale DVD processes.

This system will require a computerized database system to run. So, we need to produce designs to implement. For task 1, some required DFD will be produced. For task 2, file design and relationships is required. ERD will be produce. Task 3 is to create ELH for DVD file. In task 4, normalization for required entities and data dictionary will be needed. Task is to create prototype user interface for searching, loan, member registration processes. For task 6, analysis and assumption, review, advantages and disadvantages, site preparation and hardware requirement will be produced.


  • Context Diagram
  • Aim and Objective
  • There are many benefits by using the new system. For the whole system, all files can link together e.g. if we just know the sale ID, we can know all the information of DVDs sold. This can reduce the time consuming. One of the main objectives of new system is to reduce time consuming. Behind this, staffs can work comfortably and customers can more satisfy. In Loan and Return, those will obviously be fast and easy.

    Member can be easily checked with new system and all member information can be easily viewed. Aim also leads to the return process. Due date can be obviously viewed, and it is automatically calculated when loan. Data can be easily updated. The new system also gives professional images for DVD store. So, customer entering can be increased than before.

  • Data Flow Diagram with descriptions

Process Descriptions

1. Member Registration

This process is responsible for shop assistants. The manager will help with this duty during busy period. Customers come DVD store and make register. In member registration process, customers can also enquiry for requirements in register. Customer must fill a form and pay member fees and photos. After one week, shop assistant will give member cards. Every after DVD store got about 30 member forms, shop assistant transfers these data to the computerized database.

2. Updating Member

Shop assistant is responsible for this process. When members want to change their information, tell staff. And shop assistant checks and changes member information.

3. Searching Item

Member can search catalogue for the availability of items for loan using public workstation. Member chooses a search type of title, keyword, category and director.

4. Registering Loan

This process is responsible for shop assistant (also manager in busy period). Shop assistant checks member card. Loan period of 24 hour, 48 hour or 1 week is chosen and calculate total fee. Payment for the loan is made before the DVD being taken from the shop. No member can have more than 5 DVDs on loan at any time. Members who still have a current DVD loan that has not been return will be refused for next loans until the DVD has been returned and the fee is paid. All loaned processes are recorded. DVD status is changed as "loan" for each loan. This process is made using remaining workstations that can be used only for staff.

5. Return of DVDs

Responsible person is like the loan process. Checking the due date is made. Overdue fee must be paid by member for every 24 hour period after the due date. Shop assistant records the overdue process in the Return file. DVD status is re-changed as "return" for next loan. Then this member can make next loan. This process is made using remaining workstation.

6. Updating DVDs

Manager is a responsible person for this process. This process is not concerned with adding new DVD. Manager decides a damage DVD to remove or to change it as old DVD status that is made to sell the DVDs to customers. Manager also decides how much discount is given to the items.

7. Ordering new DVD

This process is responsible for manager only. When new DVDs have been produced around the world or any DVD in DVD store is damage, this process is made to add or to refill the new DVD. Manager orders new DVDs from a number of DVD Distribution Company. Supplier and DVD information are recorded.

8. Selling older DVDs

This process is responsible for shop assistant. Old DVDs are sold to both members and no members with discounts. Invoices are given to customers and recorded. Items that were sold to customer are removed from DVD list.

External Entity Definitions

  • Customer
  • Customers can register as member to be able to hire DVD. They can buy old DVDs from DVD store with discount.

  • Member
  • Customers who have registered in DVD store are identified as members. Members always have to take their card to hire DVDs. Members can buy old DVD with discount and can change their information as necessary.

  • DVD Distribution Company

They are suppliers for DVD store. DVD store's manager orders new DVDs from these companies. They have DVDs of movies from around the world.

Data Store Contents

Member file

This file is used to record members of DVD store. This member can make loan.

DVD Title

DVD titles are recorded in the file and not record all DVDs as much as quantity.

DVD file

This file is used to record all DVDs to borrow in DVD store. An attribute, "status", is used to record the availability of DVD such as loan, return, new or old. DVDs with old status are sold to customer or member.


All loan information is recorded in this file. Loan date is included.

Loan Detail

Loan details are recorded in this file. DVDs loaned and their information is recorded.


It generally used for overdue information. It is linking with Loan file.

Return Detail

Return DVD and their overdue process are recorded detail. Overdue fee and date are recorded.

Order file

All order processes are recorded in this file. Purchase date is recorded.

Supplier file

This file is used to recorded supplier of DVD store. Supplier means DVD Distribution Company and used to contact them for order process.

Order detail

It includes detail information of all purchased items.

Sales file

It is used to record Sale process that old DVD is sold to the customer.

Sale detail file

It stores the detail of sale process and includes sold DVD information.

Dataflow Description

Member Registration

Enquiry for new member registration - Customer enquiry to DVD stores to know requirement for member registration.

  • Give required information - Tell customer for registration information.
  • Request new member form - Customer want to register and request member form.
  • Give new member form - Gives member form to customer.
  • Return filled form - Customer fills the form and returns it.
  • Record member information - Transfer member data from the form to computerized database.

Updating Member

  • Request for update information - Member requests to change their information given.
  • Give changed information - Member gives changed data.
  • Check member - Reads member file to check whether this member is real or not.
  • Update member information - Edits member information in Member file.

Searching Item

  • Search by title, keyword, director and category - Members search by their required ways in public workstation.
  • Take DVD status to view availability- Take DVD availability from DVD status that can be loan, return, new or old.

Registering Loan

  • Hire available items - Member select available items and hire them.
  • Choose loan period - Member choose loan period of 24 hours, 48 hours or 1 week.
  • Check member - Read member file to check whether customer is member or not.
  • Check for return - Read Loan file to check whether this member has returned previous DVDs or not.
  • Update DVD status - Change DVD status as "Loan".
  • Record Loan information - Records the loan information in Loan file.
  • Record Loan detail - Records loan detail to Loan Detail file.

Return of DVDs

  • Return DVD - Member return the hired DVDs.
  • Request overdue fees if overdue - If member is overdue, shop assistant request for overdue fee.
  • Check date - Searches the loan information in Loan file to check due date of the member who is returning.
  • Record return detail with overdue - Return Detail and overdue process are recorded.
  • Update DVD status - Change DVD status as "Return".
  • Show damage DVDs - Shop assistant reports the damage DVDs to manager.

Updating DVDs

  • Check purchased date - Checks purchased date of damage DVD in Order files to know its life.
  • Remove if no use - Removes the DVD that does not used in DVD store.
  • Update DVD status - Change DVD status as "Old" that cannot be hired.

Ordering New DVD

  • Enquiry for new DVD titles - Enquiries for new DVDs from DVD Distribution Company to buy.
  • Show list - Distribution Company shows available new DVD list.
  • Check DVD exist or not - Check DVD whether it already exists or not to purchase it.
  • Record order information - Records each order process and not detail to items.
  • Add new DVD information - Add new DVD title and information.
  • Add DVDs to borrow- Add new DVDs to DVD file to hire.
  • Record order detail with item - Stores order detail information.

Selling Older DVDs

  • Request for old DVD - Customer requests for old DVD to buy.
  • Take old DVD information - Take old DVD information from DVD file to calculate discount price and to show date to customer.
  • Remove after sell - After customer buys old DVD, this DVD is completely removed from DVD file.
  • Record sale - Record sale process in Sales file to produce yearly or monthly report.
  • Record sale detail with sold item - record sale detail information.

Analysis and Assumption

For Task 1, Context diagram and DFD level-1 will be drawn. Physical DFD of proposed system will be needed. The external entities, customer, member and DVD Distribution Company will be produced. Shop assistant and manager will be responsible in private workstation and public workstation can only be related to member. Enquire for registration is combined to the Member Registration process. New DVD and old DVD will be stored in the same file. Updating DVD process is needed to be produced to change the unused or damage DVDs to old DVDs that will be included in the sale process. Searching is separated from loan process because each process uses different workstations. Loan record is deleted when return the DVD and both this process and overdue process are recorded in return file. Overdue process and return process are combined.

For Task 2, both new DVDs and old DVDs will be stored in DVD file. This DVD file can contains DVDs that have same title with different ID. DVD title file is also produced. One title in DVD title file is related to many same titles in DVD file. DVD file is intended to be used in loan process and DVD title is only for searching which DVDs are existed. Loan, sale and return entities are related to DVD file. Only the order entity relate to DVD title. These entities are related to DVD and DVD title in the form of many-to-many. So, loan detail, return detail, sale detail and order detail are needed to be produced. A member may not always borrow any DVD. And also, a DVD may not always be loaned. So, they are optionally related to loan. In ERD, Return is connected to DVD instead of connected to Loan. And then, a DVD may not always be sold to customer. So, DVD and sale entity are optionally related. In sale entity, customer or member who buys the DVD will not be recorded. So, Sale has no relationship with customer or member. A supplier can be related with many orders.

For Task 3, Entity Life History for DVD entity will be drawn. DVD entry will be when ordering new DVD. DVD status of that new DVD will be given as 'New'. This 'New' status can be only once and cannot be iteration. Midlife of this ELH will be changing of DVD status. When member loans the DVD, status will be changed to 'Loan'. When return, it will be changed to 'Return'. When DVD is old or damage, this status will be given as 'Old' that is the mark to sell. Changing of DVD status will be repeated. 'Loan', 'Return' and 'Old' will be selection because DVD status can only be possible one of them at once. The end of a DVD is when it is damage or sold.

In Task 4, Normalization of order form, loan form, return form and sale form are needed to be produced. DVD entry is combined with order form. One order to a supplier will be one order form. So, purchase date and supplier ID is single. And, it is worked with DVD title file recording No. of DVD. DVD store order multiple same DVD, one for store as original and the rest for loan process. Order Detail will be developed. In loan form, loan price of all DVDs are calculated in the base of price for 24 hours. If member choose 2 days, unit loan price will be double. In a loan form, many DVDs (maximum 5 DVDs) can be contained and a member is recorded. Loan Detail will be developed. Return form works with DVDs that are loaned. It aims to be recorded overdue process. Overdue fee is calculated by loan price for 24 hours. Many loans of a member can be one return and also one loan can be many returns. Return Detail is developed. In sale form, system will not record customer. Sale detail is produced. Data Dictionary is also needed to be produced in Task 4. Data element, data structure, data store and data flow required will be produced. Data flow is related with DFD and the rest are with file design.

For Task 5, prototype and validation checking will be produced. Prototype includes draft screen design and screen design for search form, loan form and member registration form. In search form, it will contain one text box with four radio buttons. These radio buttons will be search types including title, director, category and keyword. 'Show all' button is put. In loan form, member ID can be chosen with combo box DVD that is loaned will be added to the loan table. Before adding, it needs to choose loan period and calculate loan fee. Expected return date will be calculated automatically. DVDs in the table can be allowed to be removed. And then, put 'Hire' button to save this process and table. In member registration, member ID will be set automatically. So, no need to check for duplication of member ID in validation checking. Screen design will be produced using Visual Basic 2005 program.


I made the complete tasks that are ready to implement. But it still needed. For task 1, I only produced the physical DFD of the proposed system. Current system is not included and logical views are needed. And then, I combined return and overdue process. Changing DVD status to 'Old' was separated as a process.

For task 2, I separated DVD title file and DVD file. DVD file is for loan and sale process. In ERD, I connect the Return entity with the DVD instead of connected to Loan. It is a result of Normalization. I also describe optional relationships in task 2.

For task 3, I drew changing DVD status in iteration in midlife. It includes changing 'Loan', 'Return' and 'Old' in the form of selection. It may be difficult to know flow. So, I set State Indicators.

For Task 4, after normalization, order detail, loan detail, return detail and sale detail are developed. I made Return file not directly relate with Loan file and I made relationship between Return file and DVD file. It has some advantages and disadvantages (see in Advantages and Disadvantages section). Customer who buys the DVD is not recorded. After drawing data dictionary, I updated file design and some words used.

In task 5, I made not only Search form, Loan form, Member Registration form but also Return form. In search form, I made only one text box for different searching type. I made loan table in loan form with Add, Remove and Clear buttons. Loan No., Return No., Order ID and Member ID are designed to be set automatically. Member registration form is simple and not given update or delete.

After complete Task 1 to 5, I improve my understanding upon SSADM and detail of system life cycle. I also know how much important each technique and how they work. This assignment makes my time valuably.

Advantages and Disadvantages

In Task 1, combining the Return and Overdue process can make the user who views this DFD can be misunderstood. By separating Changing DVD to old status as an individual process, it can be clear who is responsible for this process and when it is made. In DFD, Selling older DVDs process is made with customer. So, the reader can ambiguous whether member can buy old DVDs or not.

In Task 2, by separating DVD and DVD title file, DVDs can be easily updated because it only need to change once in DVD title and all DVDs that are related with changed DVD title are no need to be changed. I also describe optional relationships in task 2, so it avoids misunderstanding.

In Task 3, producing of State Indicators may help reader to know flow of ELH. E.g. 'Return' status does not be given, while a DVD does not even have loan.

In Task 4, I produce order detail, loan detail, return detail and sale detail in Normalization. They can resolve the problems of relationships between entities that will found when implement. Connecting Return file directly with DVD file instead of connecting to Loan file can seen to be complex but it has advantages that should be. By doing this, many loans of a member may be one return and also one loan can be many returns. Disadvantage is that it will need some checking when implement because return DVD cannot be known its loan process. And also, it is wrong in theories and can be occurred problems in implementation. In Data Dictionary, Return file and sale file has a few problems. These two have no flow out. So, they will have too many records.

In Task 5, making only one text box for search bar with different types of radio buttons can be weak because searching needs correct spelling (e.g. category - comic/ comics). But it is less complex to use. By producing loan table in Loan form, user can add or remove the DVD before hire. After overall, it has many advantages with a few disadvantages.

Site Preparation

Office Layout and Furniture

For implementation of computer system, we need to change the manual routine of the DVD store to facilitate new procedures. New furniture can also be required. For the public workstation, a desk is needed. This should be placed where anybody can see and freely to use. Remaining workstation should be placed at the loan counter. So, larger or different-shaped desk may be needed. Chairs should be suitable for that activity and make user comfortably enough. When we are deciding these processes, the user who will use in this activity should be involved.

Office Alteration

This alteration depends on computer equipments and air conditioning requirements. This should be taken at the appropriate time. Generally, alterations should be completed before computer equipments are moved because they can be easily damaged by dust and damp.

Heat Dissipation

We also need to consider heat that generate from computer equipments. This depends on allocation of machines. We should make better air flow and prevent from direct sunlight to the computer devices.

Power Supply

One of the main contents we should consider is power supply. There should be enough electrical outlets and capacity of the circuit should be sufficient from load of the machines. Isolators may be required if necessary to prevent surges from other electrical equipment. We should put Uninterruptible Power Supply (UPS) to prevent from suddenly power cut.

Hardware Requirements

When getting start, some of the computer devices are needed to buy 3 quantities for two public workstations and one remaining workstation. Public workstations will not need hard disk that has great capacity. Printer and DVD drive are put in remaining workstation.