COMP3241 E-Commerce Technologies Richard Henson University of Worcester November 2013

Week 9: Mechanism of Shopping System, Part 3 Objectives: Use a pre-defined control to send data to either the shopping cart or a database, depending on the way the parameters are used Use a further control to save order data to a database table for use in customer fulfillment Provide a final link to a payment system that will allow the order to be processed and physically sent to the customer

You’ve already achieved a lot: Database Scripts Controls Connectivity Just one more step (online order…) and you’ll be there!

You’ve designed and created a database containing suitable tables and fields…

Used webxel controls to create a “click to buy” system complete with shopping cart

(Perhaps…) Used webxel controls to complete a login/register customer details system? If still mystified all should become clear by the end of this lecture…

Why all that “Validation” stuff? Two reasons: make sure the data is of the right type e.g. telephone number not put in email address text box make sure only data of the right type gets sent to the cart or database could get memory overflow… or failed Database write… (Neither would impress the customer!)

What sort of Button should be used? Data being presented on a HTML form… <form> It should therefore be extracted with a HTML submit button near the bottom of the form… before </form> will send the data to a location specified on the form “header” (e.g. runat=“server”) not to be confused with buttons used to run a small chunk of code

What happened to the customer data anyway? Once you completed the last exercise, you might have expected new order data to be written to the database… but nothing appeared in “orders” All the data for the order now resides in the cart: orderID customerID the various aspects of the order needed for the onscreen invoice

And the rest of the Data? What actually happened was that the order data was written to the cart under the label “orderID” and the customer details were written to the customers table The system was not programmed to write order data (yet…) this won’t happen until they have acknowledge the onscreen order (i.e. they agree to pay…)

Why “Save to Cart”? Data quickly saved locally and easily accessible when it needs to be extracted e.g. address fields for screen invoice If screen invoice not accepted, and “customer” leaves “customer” data easily removed… also good for “data protection” – personal data only ever saved to memory

Passing the CustomerID Parameter Page Customer ID value sent as e.g. “CustomerID” cust data WriteToDB scripts Shopping Cart fields sent To shopping cart

Saving and Displaying the Order On Screen Invoice is displayed (summary.aspx) Action only happens when user clicks on “Pay Now”… Orderdetail Record written again uses the WriteToDB control writes “OrderLine” Cart fields to appropriate Table

Writing the Order Details to Screen (and Database) Shopping Cart Product ID value Customer ID value Contains all data needed to write orderline to disk (with primary key OrderLineID) Remote DB Screen display Write to DB control Order details

More about that multivalue WebXel control property: Called “field mappings” You’ve used these a couple of times now: AddFromDB… populating CartFields from the Products table WriteToDB… populating CartFields from the customer details form Either tagged as “Parameters” or “Fields”

Using “Field Mappings” with Visual Studio This feature was intended to take the hard work out of parameter passing… unfortunately not compatible with Visual Studio “design mode”… so errors generated! and “properties” can’t be used the insert values (as they could with “Cart”) fields could be added as “cartfields” or “databasefields” need to refer to the WebXel control “help” for exact syntax of controls with “field mappings”

Explaining Parameter Passing for a new customer Customer puts their data into textbox control Customer presses “submit” button to allow the WriteToDB control to run Data captured and sent to cart and Database with appropriate fieldnames CustomerID field essential for both Cart and Customers datatable

Converting between DataTypes Sometimes necessary when passing parameters to change the datatype known in “C” programming as “casting” Easy to achieve a cast… e.g. number to a string would just add .tostring() after the expression can be used to change data to currency format Variable (integer) Expression plus .tostring() Variable (string)

Saving The Order itself Handled by the WebXelCart:SaveOrder control works in a similar way to WritetoDB but writes appropriate cart fields to the ORDERS table Important differences between WritetoDB and SaveOrder in this coding: both write cart fields to a database table

Payment Next section presented after invoice has been acknowledged… would normally transfer through secure connection to a merchant services provider page once payment has been authorised and taken… customer returns to “come again soon” page then exits the website session cookie (i.e. cart) erased

The Write Up for assignment 2 (40% of marks; 1150 words)

How to Document… Projects usually have four phases: Analysis Design Implementation Evaluation Your assignment 2 can be considered to be a mini-project…

Analysis Normally the most important part… You already know that in this case, the analysis has been done for you… You already know that you need to produce a shopping cart system from the assignment brief a payment system doesn’t need to be produced, but there should be a “dummy” payments page

Design This should cover: web page design database design something about the scripts required to interact effectively between: remote database local memory storing the cart fields screen A test plan…

Implementation Coding Testing We’ll talk about this next week… That’s all… for this week