Download Ch.20 Abridged

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20
Database, SQL and
ADO.NET
 2006 Pearson Education, Inc. All rights reserved.
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It is a capital mistake to theorize before one
has data.
— Arthur Conan Doyle
Now go, write it before them in a table, and note it in
a book, that it may be for the time to come for ever
and ever.
— Holy Bible, Isaiah 30:8
Get your facts first, and then you can distort them as
much as you please.
— Mark Twain
I like two kinds of men: domestic and foreign.
— Mae West
 2006 Pearson Education, Inc. All rights reserved.
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OBJECTIVES
In this chapter you will learn:
 The relational database model.
 To write basic database queries in SQL.
 To add data sources to projects.
 To use the IDE's drag-and-drop capabilities to display
database tables in applications.
 To use the classes of namespaces System.Data
and System.Data.SqlClient to manipulate
databases.
 To use ADO.NET's disconnected object model to
store data from a database in local memory.
 To create XML documents from data sources.
 2006 Pearson Education, Inc. All rights reserved.
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20.1
Introduction
20.2
Relational Databases
20.3
Relational Database Overview: Books Database
20.4
SQL
20.5
20.4.1
Basic SELECT Query
20.4.2
WHERE
20.4.3
ORDER BY
20.4.4
Merging Data from Multiple Tables: INNER
20.4.5
INSERT
Statement
20.4.6
UPDATE
Statement
20.4.7
DELETE
Statement
Clause
Clause
JOIN
ADO.NET Object Model
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20.6
Programming with ADO.NET: Extracting Information from a
Database
20.6.1
Displaying a Database Table in a DataGridView
20.6.2
How Data Binding Works
20.7
Querying the Books Database
20.8
Programming with ADO.NET: Address Book Case Study
20.9
Using a DataSet to Read and Write XML
20.10 Wrap-Up
20.11 Web Resources
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Data Sources window
Data menu
Fig. 20.23 | Adding a data source to a project.
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Fig. 20.24 | Choosing the data source type in the Data Source Configuration Wizard.
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Fig. 20.25 | Adding a new data connection.
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Fig. 20.26 | Choosing the Books.mdf data connection.
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Fig. 20.27 | Saving the connection string to the application configuration file.
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Fig. 20.28 | Choosing the database objects to include in the DataSet.
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Data Sources window
Fig. 20.29 | Viewing a data source listed in the Data Sources window.
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Fig. 20.30 | Viewing a database listed in the Solution Explorer.
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authorsBindingNavigator
authorsDataGridView
Component tray
Fig. 20.31 | Design view after dragging the Authors data source node to the Form.
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Move to first row
Move to previous row
(a)
Move to next row
Delete the current row
Add a new row
Move to last row
Save changes
(b)
Currently selected row
Fig. 20.32 | Displaying the Authors table in a DataGridView.
 2006 Pearson Education, Inc. All rights reserved.
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Fig. 20.33 | Data binding architecture used to display the Authors table of the Books
database in a GUI.
 2006 Pearson Education, Inc. All rights reserved.
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// Fig. 20.34: DisplayTable.cs
// Displays data from a database table in a DataGridView.
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using System;
using System.Windows.Forms;
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namespace DisplayTable
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public partial class DisplayTableForm : Form
(1 of 2)
{
public DisplayTableForm()
{
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InitializeComponent();
} // end constructor
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// Click event handler for the Save Button in the
// BindingNavigator saves the changes made to the data
private void authorsBindingNavigatorSaveItem_Click(
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Outline
DisplayTable.cs
{
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object sender, EventArgs e )
{
this.Validate();
this.authorsBindingSource.EndEdit();
this.authorsTableAdapter.Update( this.booksDataSet.Authors );
} // end method authorsBindingNavigatorSaveItem_Click
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Inc. All rights reserved.
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// loads data into the booksDataSet.Authors table,
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// which is then displayed in the DataGridView
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private void DisplayTableForm_Load( object sender, EventArgs e )
{
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// TODO: This line of code loads data into the
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// 'booksDataSet.Authors' table. You can move, or remove it,
// as needed.
this.authorsTableAdapter.Fill( this.booksDataSet.Authors );
Outline
DisplayTable.cs
(2 of 2)
} // end method DisplayTableForm_Load
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} // end class DisplayTableForm
35 } // end namespace DisplayTable
(a)
(b)
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Inc. All rights reserved.
19
Dataset Designer
TitlesTableAdapter
Fig. 20.35 | Viewing the BooksDataSet in the Dataset Designer.
 2006 Pearson Education, Inc. All rights reserved.
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Fig. 20.36 | TableAdapter Query Configuration Wizard to add a query to a TableAdapter.
 2006 Pearson Education, Inc. All rights reserved.
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Fig. 20.37 | Choosing the type of query to be generated for the TableAdapter.
 2006 Pearson Education, Inc. All rights reserved.
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Fig. 20.38 | Specifying a SELECT statement for the query.
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(a)
Fig. 20.39 | Query Builder after adding a WHERE clause by entering a value in the Filter
column. (Part 1 of 2.)
 2006 Pearson Education, Inc. All rights reserved.
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(b)
Fig. 20.39 | Query Builder after adding a WHERE clause by entering a value in the Filter
column. (Part 2 of 2.)
 2006 Pearson Education, Inc. All rights reserved.
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Fig. 20.40 | The SELECT statement created by the Query Builder.
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Fig. 20.41 | Specifying names for the methods to be added to the TitlesTableAdapter.
 2006 Pearson Education, Inc. All rights reserved.
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Fig. 20.42 | Dataset Designer after adding Fill and Get methods to the
TitlesTableAdapter.
 2006 Pearson Education, Inc. All rights reserved.
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// Fig. 20.43: DisplayQueryResult.cs
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// Displays the result of a user-selected query in a DataGridView.
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using System;
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using System.Windows.Forms;
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Outline
namespace DisplayQueryResult
7 {
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public partial class DisplayQueryResultForm : Form
{
public DisplayQueryResultForm()
{
InitializeComponent();
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} // end DisplayQueryResultForm constructor
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// Click event handler for the Save Button in the
// BindingNavigator saves the changes made to the data
private void titlesBindingNavigatorSaveItem_Click(
DisplayQuery
Result.cs
(1 of 5)
object sender, EventArgs e )
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{
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} // end method titlesBindingNavigatorSaveItem_Click
this.Validate();
this.titlesBindingSource.EndEdit();
this.titlesTableAdapter.Update( this.booksDataSet.Titles );
 2006 Pearson Education,
Inc. All rights reserved.
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// loads data into the booksDataSet.Titles table,
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// which is then displayed in the DataGridView
private void DisplayQueryResultForm_Load(
object sender, EventArgs e )
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Outline
{
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// TODO: This line of code loads data into the
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// 'booksDataSet.Titles' table. You can move, or remove it,
DisplayQuery
Result.cs
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// as needed.
this.titlesTableAdapter.Fill( this.booksDataSet.Titles );
(2 of 5)
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// set the ComboBox to show the default query that
// selects all books from the Titles table
queriesComboBox.SelectedIndex = 0;
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} // end method DisplayQueryResultForm_Load
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Inc. All rights reserved.
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// loads data into the booksDataSet.Titles table based on
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// user-selected query
private void queriesComboBox_SelectedIndexChanged(
object sender, EventArgs e )
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{
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// fill the Titles DataTable with
// the result of the selected query
switch ( queriesComboBox.SelectedIndex )
{
case 0: // all books
titlesTableAdapter.Fill( booksDataSet.Titles );
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break;
case 1: // books with copyright year 2006
titlesTableAdapter.FillWithCopyright2006(
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booksDataSet.Titles );
break;
case 2: // How to Program books, sorted by Title
titlesTableAdapter.FillWithHowToProgramBooks(
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Outline
DisplayQuery
Result.cs
(3 of 5)
booksDataSet.Titles );
break;
} // end switch
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} // end method queriesComboBox_SelectedIndexChanged
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} // end class DisplayQueryResultForm
63 } // end namespace DisplayQueryResult
 2006 Pearson Education,
Inc. All rights reserved.
31
(a)
Outline
DisplayQuery
Result.cs
(4 of 5)
(b)
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Inc. All rights reserved.
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(c)
Outline
DisplayQuery
Result.cs
(5 of 5)
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Inc. All rights reserved.
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// Fig. 20.44: AddressBook.cs
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// Allows users to manipulate an address book.
using System;
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using System.Windows.Forms;
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namespace AddressBook
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{
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Outline
AddressBook.cs
public partial class AddressBookForm : Form
(1 of 3)
{
public AddressBookForm()
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{
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// BindingNavigator saves the changes made to the data
private void addressesBindingNavigatorSaveItem_Click(
object sender, EventArgs e )
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{
InitializeComponent();
} // end AddressBookForm constructor
// Click event handler for the Save Button in the
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this.Validate();
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this.addressesBindingSource.EndEdit();
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this.addressesTableAdapter.Update(
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this.addressBookDataSet.Addresses );
} // end method bindingNavigatorSaveItem_Click
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Inc. All rights reserved.
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// loads data into the addressBookDataSet.Addresses table
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private void AddressBookForm_Load( object sender, EventArgs e )
{
// TODO: This line of code loads data into the
// 'addressBookDataSet.Addresses' table. You can move,
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// or remove it, as needed.
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this.addressesTableAdapter.Fill(
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this.addressBookDataSet.Addresses );
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} // end method AddressBookForm_Load
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// loads data for the rows with the specified last name
// into the addressBookDataSet.Addresses table
private void findButton_Click( object sender, EventArgs e )
{
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// fill the DataSet's DataTable with only rows
// containing the user-specified last name
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addressesTableAdapter.FillByLastName(
addressBookDataSet.Addresses, findTextBox.Text );
} // end method findButton_Click
Outline
AddressBook.cs
(2 of 3)
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// reloads addressBookDataSet.Addresses with all rows
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private void browseAllButton_Click( object sender, EventArgs e )
{
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// fill the DataSet's DataTable with all rows in the database
addressesTableAdapter.Fill( addressBookDataSet.Addresses );
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Inc. All rights reserved.
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findTextBox.Text = ""; // clear Find TextBox
} // end method browseAllButton_Click
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Outline
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} // end class AddressBookForm
55 } // end namespace AddressBook
AddressBook.cs
(a)
(b)
(3 of 3)
(c)
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Inc. All rights reserved.
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Fig. 20.45 | Selecting the control(s) to be created when dragging and dropping a data source
member onto the Form.
 2006 Pearson Education, Inc. All rights reserved.
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Fig. 20.46 | Displaying a table on a Form using a series of Labels and TextBoxes.
 2006 Pearson Education, Inc. All rights reserved.
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Fig. 20.47 | Dataset Designer for the AddressBookDataSet after adding a query to
AddressesTableAdapter.
 2006 Pearson Education, Inc. All rights reserved.
39
Fig. 20.48 | Design view after adding controls to locate a last name in the address book.
 2006 Pearson Education, Inc. All rights reserved.
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Fig. 20.49 | Viewing the DataBindings.Text property of a TextBox in the Properties
window.
 2006 Pearson Education, Inc. All rights reserved.
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// Fig. 20.50: XMLWriter.cs
// Demonstrates generating XML from an ADO.NET DataSet.
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using System;
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using System.Windows.Forms;
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{
XMLWriter.cs
public partial class XMLWriterForm : Form
{
public XMLWriterForm()
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{
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InitializeComponent();
} // end XMLWriterForm constructor
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// BindingNavigator saves the changes made to the data
private void playersBindingNavigatorSaveItem_Click(
(1 of 3)
// Click event handler for the Save Button in the
object sender, EventArgs e )
{
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this.Validate();
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this.playersBindingSource.EndEdit();
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Outline
namespace XMLWriter
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this.playersTableAdapter.Update( this.baseballDataSet.Players );
} // end method bindingNavigatorSaveItem_Click
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Inc. All rights reserved.
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// loads data into the baseballDataSet.Players table
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private void XMLWriterForm_Load( object sender, EventArgs e )
{
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// TODO: This line of code loads data into the
// 'baseballDataSet.Players' table. You can move,
// or remove it, as needed.
this.playersTableAdapter.Fill( this.baseballDataSet.Players );
Outline
XMLWriter.cs
(2 of 3)
}
// write XML representation of DataSet when Button clicked
private void writeButton_Click( object sender, EventArgs e )
{
// set the namespace for this DataSet
// and the resulting XML document
baseballDataSet.Namespace = "http://www.deitel.com/baseball";
// write XML representation of DataSet to a file
baseballDataSet.WriteXml( "Players.xml" );
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Inc. All rights reserved.
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// display XML representation in TextBox
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outputTextBox.Text += "Writing the following XML:\r\n" +
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baseballDataSet.GetXml() + "\r\n";
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} // end method writeButton_Click
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} // end class XMLWriterForm
49 } // end namespace XMLWriter
Outline
XMLWriter.cs
(3 of 3)
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Inc. All rights reserved.
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<?xml version="1.0" standalone="yes"?>
<BaseballDataSet xmlns="http://www.deitel.com/baseball">
<Players>
<PlayerID>1</PlayerID>
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<FirstName>John</FirstName>
<LastName>Doe</LastName>
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<BattingAverage>0.375</BattingAverage>
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<PlayerID>2</PlayerID>
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<FirstName>Jack</FirstName>
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<LastName>Smith</LastName>
<BattingAverage>0.223</BattingAverage>
</Players>
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<Players>
<PlayerID>3</PlayerID>
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Outline
Players.xml
</Players>
<Players>
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<FirstName>George</FirstName>
<LastName>O'Malley</LastName>
<BattingAverage>0.344</BattingAverage>
</Players>
21 </BaseballDataSet>
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Inc. All rights reserved.