distributed retail chain

8/6/2019 Distributed Retail Chain

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The system basically keeps track of two types of information:

merchandise and personnel. The stores are spread across

zones/regions such that during situations where stock is less or

high in quantity the system can make decision to transfer these

items across stores. Also it is possible for Managers to add stores,zones and regions depending on their position in the hierarchy.

Eventually the dynamic and distributed architecture and data

collection helps in making decision such as adding new stores

where demand is large .The queries and scope are explained in

Design specifications.

Design:

1. There is a 4 level hierarchical structure where National manager

lead regional manager, regional managers lead zonal manager and

finally zonal managers lead store manager. Store managers head

the store and cashiers report to the store manager


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2. The User interfaces are a simple login screen which will direct

an employee to their role based web pages. We consider that a user

is a cashier in the store and is the last person in contact with a

customer and does the transaction on customers behalf. The other

role is a manager (Store, zone, regional and national).

3. Following are the list of queries and there scope of execution

These have been modified and are different from the original

specification given at

http://www.cs.odu.edu/~mukka/cs795sum10.net/Project/projspec.p

df

Merchandize monitoring

U1. Change price: Item ID, Price, date effective (sale price being

changed)

- When executed at a retail-store, price only at that store ischanged. If executed at higher levels, all retail-stores below

that node will implement that operation. For example, if R1

executes this command, then all retail stores under Z1 and Z2

implement the change in price.

U2. Add an item: Item ID, description, price. (A new item is to be

added)

-Only Store manager can add an item

U3. Add to Inventory: Item ID, quantity (Items arrived from

manufacturer)


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-We have implemented a logic where a store add from

inventory only as the last resort when inter store transfer is not

possible.

U4. Sales: Item ID, quantity (A customer is purchasing)

- Sales information is implemented only by store managerU5. Remove item: Item ID (Discontinue the item)

- A store manager can remove a itemU6. Inter store-transfers: Item ID, quantity, from-store-ID, to-store-ID (Transfer stock from one store to another)

- Regional manager sets a minimum stock of any item a storemust hold. If the stock is less the region manager can

generate report identifying stores from where he can transfer

stock. This check is done for stock available within the same

region or from another zone within the region.

- Inter store transfer between regions is not allowed as it doesnot help economically, the region can add from inventory as

opposed to adding from another region to reduce cost of

transportation

U7. Query item: Item ID (Customer service wants to know

information about the item)

- A cashier can query for an item to know its availability andgeneral product information.


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Employee Monitoring System

Q1. Add a new employee: Employee ID, SSN, name, sex (male or

female), job title, and employment begin date, and current salary.

- A store manager can add an employee, Also when a zonal

manager adds a store he can add a store manager immediately after

that, this applies to a regional manager after creating a zone and

can add a zonal manager.

Q2. Remove employee: Employee ID (Employee resigned or

fired)

- A store manager can remove an employee

Q3. Display number of employees

- Can be executed at all levels

Q4. Total monthly payroll (Sum of monthly salaries of all

employees)

- Can be executed at all levelsQ5. Employee information: Employee ID (Given employee ID

shows all information pertaining to that employee)

- Can be executed at all levels

4. There are distributed database servers where each store, zone

and region keeps track of their sub level databases and also the

national office acts as the last measure back up in case of failure of

all servers.


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5. There are web services available for client applications at all

nodes helping in various operations. (More details in

implementation).

Features:

Since the coursework in development in .NET, we have used many

of the .NET features

Basic Features Regular Expression, date validation, calendar

controls and range validation, XML based configuration files

ADO.NET Datasets, Data Adapters and Data tables

ASP.NET security Role base security for Forms authentication

Web services Extensive use of webservices

.NET Remoting This is a simple application which is not

integrated into project but used for demo just to show the

importance of remoting in intranet applications

Crystal Reports Business objects crystal reports for generating

reports for various queries pertaining to Employee monitoring and

few merchandize monitoring such as sales and product information

Implementation:

This part of document describes the implementation based 4

categories Security, Availability, Response time and dynamicnature of the system.

Firstly we have created database at every node and each database

has 3 tables mainly store_product_info, sales_table and

employee_details. The same tables are used at all levels


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We used the Microsoft Visual Studio 2005 and SQL Server

Developer Edition with Visual C# as the Language.

To illustrate the distributed nature of the project over a standalone

system we used the Enterprise manager as the networking

monitoring system.

The analogy is made that over the intranet that the databases would

be located on their own database servers as opposed to the current

setup of multiple databases on a single database server.

However extending the current project to intranet is simple as we

have used this approach.

Following is the snapshot of the enterprise manager


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Enterprise Manager

Security

Role based security for asp.net applications

We have implemented the .NET provided Role based security with

an md5 has for encryption of username and passwords.

Following code snippets shows this.

// Encrypt the cookie using the machine key for

secure transport


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string hash =

FormsAuthentication.Encrypt(ticket);

HttpCookie cookie = newHttpCookie(

FormsAuthentication.FormsCookieName,

// Name of auth cookie

hash); // Hashed ticket

Then check for the role of the login person from

the database

if (role.CompareTo("user") == 0)

Global.asax file that does the matching

if (HttpContext.Current.User != null)

{

if

(HttpContext.Current.User.Identity.IsAuthenticated)

{

if

(HttpContext.Current.User.Identity is

FormsIdentity)

{

FormsIdentity id =

(FormsIdentity)HttpContext.Current.User.Identity;

FormsAuthenticationTicket

ticket = id.Ticket;

// Get the stored user-data, in

this case, our roles

string userData =

ticket.UserData;

string[] roles =

userData.Split(',');

HttpContext.Current.User = new

GenericPrincipal(id, roles);

}

}


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Dynamic System:

To illustrate a Dynamic system we have used multiple database

servers which interact with each other based on some form of

event handlers. Creating a new store, zone is doneprogrammatically and at execution creates databases. Also store

can be reassigned across zones.

To implement this we used ADO.NET features and made extensive

use of data tables and datasets for data replication.

Response time:

Since this is a stand alone application, the response times are fast

however timeout mechanisms are implemented, In case a database

is not responsive the back up database is taken over

Availability:

For availability database tables are deleted and restored during this

system queries are redirected to backup databases (servers).

Web Services and Web methods: The names are explanatory

changePrice - web method to change price and alsoupdate respective databases

getSuperDataBase Used at a level to get upper leveldatabases needed for making updates

saleProduct Gives each products sales information setStoreProdInfo for every store and a particular

product this gives the information, this is inventory

information


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getRetailStores For every zone or region get the leafnodes ( stores )

deleteStoreProdInfo if a product is removed then theupdate is reflected

getActualDB For every login user get his/her actual dbeven if his/her db has crashed

getDataBase Get DB of the user from which he haslogged in, this could be upper DB incase of actual DB

server id down

getExistingProducts For a particular store get theproduct information

getLevel The level of node in the hierarchy getProductPrice Get the price of a particular product getProducts Get all the products in the retail store

Crystal Reports:

Business objects Crystal reports are made use of in displaying sales

and employee info.

The reports are generated even if databases are deleted or down.


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.NET REMOTING:

Below are snapshots of .Net remoting used for employee details

information. Here there are two remoting servers running on two

different TCP ports. By default the client application fetches datafrom the first remoting server as indicated by first snapshot,

Snapshot 1

However when the first remoting is killed or terminated the Client

jumps to next available server which is Server1, and fetches therequired value. This illustrated how availability is incorporated

into the project.


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distributed retail chain

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