Project Fact

Challenge

An oil depot is a big warehouse for gas and oil wholesale. In gas and oil distribution channel, gas and oil from refinery factories are initially transported and stored in oil depots, then are distributed to retail sellers and end users, such as a gas station. Our client, Duoba Oil Depot (Duoba), has more than ten gas and oil tanks. Each of them is capable of storing 1,000 to 5,000 tons of gas. And Duoba has the capability of distributing more than 1,000 tons a day.

Our goal was to build a web-based management system that would manage oil depot's day-to-day activities, and to replace inefficient and error-prone paper-based management.

Solution

After detailed discussion with Duoba, we designed an n-tiered web-based system to address the client's needs.

In this design, the requirement on a client machine is simply a browser that supports HTML 2.0. No additional installation or setup work is needed. In this project, the client had a special requirement for access control. Client machines get information from a user's card by a magnetic card reader to carry out access control. To do this, we implemented an ActiveX control that can be downloaded to a client machine and is capable of interacting with the card reader.

On server site, a Windows 2000 server is used to run Web server, which is IIS. Behind IIS is a .Net application that is responsible for generating Web pages for client machines, responding to client events, and processing business logic. Oil depot's business logic is divided into about 10 modules, such as client management, oil releasing, oil receiving, oil measure, account, warehousing, configurations, reporting and query. Each consists of several UI pages, and corresponding .Net classes. Almost all modules need to access database. A separate database layer is written to simplify database access, and to have better connection management and security management.

SQL Server database is used in the design and is running on a separate machine. Database consists of about 60 tables, and normalized and performance tuned. Stored procedure is also used for better performance.

OPC server is developed based on DCOM technology and OPC standard. The server is running as NT services. The server receives DCOM calls from .Net application, translates them to OPC calls and forwards to automation equipment. An Event subscribe ad publication mechanism is also used. This is to allow users to listen to subscribed events. When an event happens on the automation equipment, such as equipment shut down, the user will be notified.

Solution Highlights:

•　Total 50k lines of code, including C#, and C++ code
•　More than 60 database tables
•　67 Web pages
•　500 pages data conversion table used in oil measure
•　Technology used: C#, ASP.NET, ADO.NET, ActiveX control, DCOM Server,
 　automation object (Idispatch interface), stored procedure, CSS, HTC.