unit 8.2 learning objectives how data can be used – the money ball example the money ball example...

Unit 8.2

Learning Objectives• How data can be used

– The Money Ball Example

• Data Warehouses– The Role of Data Warehouses– Group Exercise

• Accessing Data in Views– Accessing data in Graphical Web Controls– Working with Templated Data– Working with Hidden Cells– Group Exercise

How

Dat

a ca

n be

use

dExample: Moneyball• Batting average• Stolen bases• Runs batted in• On-base %• Slugging %• On-base + Slugging

(OPS)

Databases

Real world ApplicationMoney Ball

Business IntelligenceMicrosoft BI, IBM Cognos

Database and Query Development

Database creation and useMS Visual Web Developer

MS SQL Server

Data warehouses

Please answer the following questions based on Intricity’s Video on Benefits of a Data Warehouse

1. What is a Data Warehouse?

2. What is the impact of the fact that databases can take in one row of data at a time?

3. When the video says “You are doing it anyway, what is it talking about?”

4. List any two benefits of data warehousing.

Collections of Rows

• GridViews and DetailsViews contain a “collection” of Rows• Each Row contains a collection of Cells

Rows

Cells

gvFees

dvFee

Locations of Cells

• DetailsView dvFee– The Fee amount (i.e. 7.5000)

• dvFee.Rows[2].Cells[1]

• GridView: gvFees ( “Select” is Column 0)– The FID of (i.e. 1) is in

• gvFees.Rows[0].Cells[1]

– The Weight Fee (i.e. 12.5) is in • gvFees.Rows[2].Cells[3]

012

0 1

012

0 1 2 3

Types of Cells: Standard and Templated

Standard cells Templates

Come from Database Yes, always sometimes

Created manually Never Always in ItemTemplates

Data type String web control (e.g. DDL)

Used for Display, edit Insert, display, edit, validation

Accessed by Cell Location Cell Location + FindControl

Accessing Data in Standard CellsIf• The cell does NOT contain a CheckBox, and • It has NOT been converted to a Template

Then• Your data is in the Text property of the Cell• Example:

Otherwise• Use the FindControl utility• Example:

Label lblFees = gvFee.Rows[3].Cells[2].FindControl(“lblFee”)) as Label;

Label lblFees = new Label();lblFee.Text = gvFees.Rows[3].Cells[2].Text;

Basic Templates GuidelinesTo create/use templates, remember three things1. Web control type (e.g. Label)2. Its name (e.g. “lblFeeDescription”), 3. Its location (e.g. in ItemTemplates ).

Why use to Templates• To add validators• To insert new values into the database

To use templated data, convert them directly into labels.

Template Example: DetailsView

Hiding data in DetailViews

The Data is NOT where you think it is

What is the location of the fee?

012

0 1

012

0 1

dvFee.Rows[2].Cells[1]

Invisible field is still here

How to tell

• Examine at the “SelectedFields” window– Fee Description is still the second field (it is row 1)– And the Fee is still the third field (row 2)

012

Finding Data in GridViews• All Data is located in the row selected by the user

The SelectedIndex is used to index the row and is -1 if no row is selected

All rows of a GridView• Use a special loop called “foreach”– Loops through a collection of rows– One row at a time

The collection being looped through

The type of object being extracted from the collection

Unit 8 L2

• For this exercise we are going to modify your Unit 5 L2 assignment, replacing the fees ListBox with a fees GridView

1. Start by Opening your ASPPub and copying your yournameU5L2.aspx files into the Unit8 folder.

2. Rename the files to yournameU8L23. Change the page heading from UNIT 5 L2… to UNIT 8

L2 WORKING GRIDVIEW

Unit 8 L2 - 2

4. Delete the fees ListBox and put a GridView in its place. Give the GridView the (ID) of gvFees

5. Click on the GridView’s SmartMenu, click the dropdown next to Choose Data Source and select <New data source>– Select SQL Database and change its ID to sdsFees– Click OK and select the connection you created in U8L1

Unit 8 L2 - 3

– Click Next, select the Fees table and select all the fields individually

– Click Next and click Text Query to see the records in the table, then click Finish

6. Apply an Auto Format to the Gridview and change its width to 300px.

7. Select Edit Columns from the GridViews SmartMenu– Select TemplateField from Available Fields and press Add

Unit 8 L2 – 4

– Click the Up Arrow key to move the TemplateField to the top of the Selected fields list

– Select FID from Selected fields and change its Visible property to false

– Select the FeeDescription field• change its HeaderText property to Description• Change its Styles, HeaderStyle, HorizontalAlign to Left

– Select the Fee field and change its DataFormatString to {0:f2}

Unit 8 L2 - 5– Click OK and then EditTemplates, you should be looking at

your new ItemTemplate• Add a CheckBox to the ItemTemplate• Change its (ID) to ckbSelect• Change its Text to Select• End Template Editing

– You should have something that looks something like this

Unit 8 L2 - 6

8. Delete the WHILE loop button and all its associate code (the easiest way to do this may be do double-click the button to get to the code, select all the click method code and delete it, switch back to design view and delete the button)

9. Delete the FOR loop button and all its associate code10. Double-click the sales tax button and locate and

delete the code used in Unit 5 to process the ListBox (leave the lines that calculate the tax and those that write to the Label)

Unit 8 L2 - 711. In place of the ListBox code write a foreach loop to

process the GridView rows:

– Find the CheckBox. Remember the data type & cast it

– Is it Checked?– Locate the Fee and add it to decFees

(remember, the invisible FID field still takes up a Cell!)

12. Run the page and try– A sales with no fees– A sales with one or more fees– Check your answers!

foreach (GridViewRow gvRow in gvFees.Rows){

Unit 8 L2 - 8

13. Once you are sure that your calculations work– Add code to reset the checkboxes

• This should be a foreach loop that– Locates the CheckBox in the GrideViewRow and– Sets its Checked property to false

14. Test the page with the same data as before to be sure you get the same answers and that the checkboxes are reset– Once you are sure the page works, link it to your MIS3200 profile page

and save your complete ASPPub to ASPNET as you have done before– Post a link to your MIS3200 portfolio page in the dropbox

Think About It!

• A DetailsView and a GridView always look like tables. Think of some applications where you might want to display data in a different way.

• A FormView shows one record at a time, like the DetailsView, but it isn’t divided into Rows and Cells. How do you think you would access data in a FormView.