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C H A P T E R 4
Designing Database
E-CommerceHassanin M. Al-Barhamtoshy
hassanin@kau.edu.sa
How This Chapter Is Structured
The main topics we’ll touch on in this chapter are:
1.Analyzing the requirement of the database and the functionality it should support
2.Creating the database structures for the application
3.Implementing the business tier objects required to make the system run, and putting a basic but functional error-handling strategy in place
4.Implementing a functional UI for the system
What Does a Product Catalog Look Like?
We need the following file entities: Products Categories Customers Orders
Database Designing
The major tables in e-Commerce database, as the following:
1- Products TableName
Category Name
Description
Vendor name
Vendor address
Vendor phone number
Price
Image file name
Database Designing
2- CategoryName
3- CustomersLast Name
First Name
Address
City
State
Zip Code
Phone Number
Credit Card Number
Database Designing
4- OrderOrder number
Date
Customer
Product
Quantity
Price
Subtotal
Shipping
Tax
Total
• After the key columns have been added, the list looks like this:Products
Product ID (primary key)
Name
Category ID (foreign key)
Category Name
Description
Price
Image file name
Vendor ID (foreign key)
VendorVendor ID (primary key)
Name
Address
City
State
Zip Code
Phone Number
CategoryCategory ID (primary key)
Name
CustomersLast Name
First Name
Address
City
State
Zip Code
Phone Number
E-mail (primary key)
Credit Card Number
OrderOrder number (primary key)
Date
OrderOrder number (primary key)
Date
Customer ID (foreign key)
Product ID (foreign key)
Quantity
Price
Subtotal
Shipping
Tax
Total
Entity Relation Database
Building a Product Catalog Application
This application’s user interface has just three pages:
1.Default.aspx displays a list of products for a category selected by the user.
2.Product.aspx displays details about a specific product selected by the user.
3.Cart.aspx is displayed when the user chooses to purchase a product.
The user interface for the Product Catalog application.
The Product List page.
The Product Detail page.
The Cart page
Designing the Product Database
It consists of three tables:
Categories
Products
FeaturedProducts
The Categories table
The Products table
The Featured Products table
Creating the database
sqlcmd -S localhost\SQLExpress -i CreateProducts.sql
The CreateProducts.sql script
USE master
GO
IF EXISTS(SELECT * FROM sysdatabases
WHERE name=’Products’)
DROP DATABASE Products
GO
CREATE DATABASE Products 3➝ ON (NAME= Product, FILENAME= ‘C:\APPS\Products.mdf’,
SIZE=10 )
GO
Creating the database
USE Products
GO
CREATE TABLE Categories ( catid VARCHAR(10) NOT NULL,
name VARCHAR(50) NOT NULL, [desc] VARCHAR(MAX) NOT NULL,
PRIMARY KEY(catid) )
GO
CREATE TABLE Products (productid VARCHAR(10) NOT NULL,
catid VARCHAR(10) NOT NULL, name VARCHAR(50) NOT NULL,
shorttext VARCHAR(MAX) NOT NULL, longtext VARCHAR(MAX) NOT NULL,
price MONEY NOT NULL, thumbnail VARCHAR(40) NOT NULL,
image VARCHAR(40) NOT NULL, PRIMARY KEY(productid),
FOREIGN KEY(catid) REFERENCES Categories(catid) )
GO
Creating the database
CREATE TABLE FeaturedProducts (
productid VARCHAR(10) NOT NULL,
featuretext VARCHAR(MAX) NOT NULL,
saleprice MONEY NOT NULL,
PRIMARY KEY(productid),
FOREIGN KEY(productid) REFERENCES Products(productid) )
GO
Adding Logic to the Site
The following paragraphs describe the highlights of this script:
1.Sets the database context to master. This is usually the default context, but it’s a good idea to set it just in case.
2.Deletes the existing Products database if it exists.
3.Creates a database named Products. The database file will be created in the C:\Apps directory. You should change this location if you want to place the database file in a different folder.
4.Creates the Categories table.
5.Note that the column name desc is a SQL keyword, so it must be enclosed in brackets.
6.Creates the Products table.
7.Creates the FeaturedProducts table.
sqlcmd -S localhost\SQLExpress -i InsertProducts.sql• Once again, you’ll need to change the server name if
you’re not running SQL Server Express on your own computer.
• You’ll know the script works if you see a series of messages like this one: (1 rows affected)
Adding some test data
Adding some test data
The application must perform the following queries:
• Retrieve all rows from the Categories table to fill the drop-down list on the Default.aspx page so the user can select a product.
• Retrieve all rows from the FeaturedProducts table to display at the top of the Default.aspx page. Note that some data is also required from the Products table, so this query requires a join.
• Retrieve all products for a given category, including the sale price indicated in the FeaturedProducts table.
• Retrieve all data for a specified product to display on the Product.aspx page. Note that this query must also retrieve the sale price from the FeaturedProducts table.
Querying the database
• The query to retrieve all rows from the Categories table uses this SQL statement:
SELECT catid, name,
[desc]
FROM Categories
ORDER BY name
Querying the database
• The query to retrieve the featured product rows requires a join to retrieve data from the FeaturedProducts table as well as the Products table:
SELECT FeaturedProducts.productid,
FeaturedProducts.featuretext,
FeaturedProducts.saleprice,
Products.name,
Products.price
FROM FeaturedProducts
INNER JOIN Products
ON FeaturedProducts.productid = Products.productid
Querying the database
• The query to retrieve the products for a given category also requires a join:
SELECT Products.productid,
Products.catid,
Products.name,
Products.shorttext,
Products.longtext,
Products.price,
Products.image,
Products.thumbnail,
FeaturedProducts.saleprice
FROM Products
LEFT OUTER JOIN FeaturedProducts
ON Products.productid = FeaturedProducts.productid
WHERE (Products.catid = @catid)
Querying the database
• The last query used by the program retrieves the data for a specific product:
SELECT Products.productid,
Products.catid,
Products.name,
Products.shorttext,
Products.longtext,
Products.price,
Products.image,
FeaturedProducts.saleprice,
FeaturedProducts.featuretext
FROM Products
LEFT OUTER JOIN FeaturedProducts
ON Products.productid = FeaturedProducts.productid
WHERE (Products.productid = @productid)”
Querying the database
The connection string used to access the Products database is stored in the application’s web.config file, like this:
<connectionStrings>
<add name=”ConnectionString”
connectionString=”Data
Source=localhost\SQLExpress;
Initial Catalog=Products;Integrated Security=True”/>
</connectionStrings>
Connecting to the database
• The last query used by the program retrieves the data for a specific product:
SELECT Products.productid,
Products.catid,
Products.name,
Products.shorttext,
Products.longtext,
Products.price,
Products.image,
FeaturedProducts.saleprice,
FeaturedProducts.featuretext
FROM Products
LEFT OUTER JOIN FeaturedProducts
ON Products.productid = FeaturedProducts.productid
WHERE (Products.productid = @productid)”
Querying the database
Downloading the Code
• Once you download the code, just decompress it with your favorite compression tool. Alternately, you can go to the main Wrox code download page at: www.wrox.com/dynamic/books/download.aspx to see the code available for this book and all other Wrox books.
• You can also download the examples from the Wrox Books Web site at:
http://eu.wiley.com/WileyCDA/WileyTitle/productCd-0764588079.html
Quiz # 2
• Design an ERD (Entity Relation Database) for e-Learning Application), includes the following:
• E-Learning Table names.
• Tables Structure.
• Tables Relation.
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