Module 7: Accessing Data by Using ADO.NET

Module Overview Overview of Data Access Reading and Writing Relational Data Reading and Writing XML Data

Lesson 1: Overview of Data Access ADO.NET Object Model XML Data Access Data Access Namespaces Choosing a .NET Framework Data Provider What Are Connected and Disconnected Operations? Accessing Data by Using the Visual Studio 2005 IDE Binding Data to Controls Demonstration: Accessing Data by Using the Visual Studio 2005 IDE

Data provider-specific classes Data provider-independent classes ADO.NET Object Model ADO.NET Connected model vs. disconnected model Data provider interfaces Data provider-specific classes Data provider-independent classes SqlConnection SqlCommand SqlDataReader SqlDataAdapter DataSet DataTable

XML Data Access XmlReader 1 XmlWriter 2 XmlDocument DOM 3 XmlElement

Data Access Namespaces Description System.Data Core ADO.NET architecture System.Data.Common Shared classes System.Data.OracleClient Classes for Oracle System.Data.OleDb Classes for OLE-DB-compatible data sources System.Data.Odbc Classes for ODBC data sources System.Data.Sql Core SQL Server classes System.Data.SqlClient Classes for SQL Server version 7.0 and later data sources System.Xml Classes for XML data sources …

Choosing a .NET Framework Data Provider Database .NET Framework Data Provider for Microsoft SQL Server SQL Server 7.0 and later Microsoft Data Engine (MSDE) .NET Framework Data Provider for OLE DB SQL Server (SQLOLEDB) Oracle (MSDAORA) Microsoft Jet (Microsoft.Jet.OLEDB.4.0) .NET Framework Data Provider for ODBC SQL Server Microsoft ODBC for Oracle Microsoft Access Driver (*.mdb) .NET Framework Data Provider for Oracle Oracle client software version 8.1.7 and later

AdventureWorks Database AdventureWorks Database What Are Connected and Disconnected Operations? Connected model Disconnected model DataSet .NET application .NET application Open connection Open connection Run commands Create DataSet Retrieve results Close connection Close connection Manipulate data Open connection AdventureWorks Database AdventureWorks Database Update tables Close connection

Accessing Data by Using the Visual Studio 2005 IDE 1 On the Data menu, click Add New Data Source 2 Define a new database connection 3 Save the connection string in the app.config file 4 Specify the tables you want in the DataSet 5 Specify a name for the DataSet

Binding Data to Controls 1 Add a control to a Windows form 2 Choose the data source for the control 3 Add queries to the table adapter, if necessary 4 Write code to fill the table in the DataSet 5 Write code to save the table in the DataSet

Demonstration: Accessing Data by Using the Visual Studio 2005 IDE Create a new data source Add a DataGridView control and set properties Bind the DataGridView control to a data source Update the data source query Add code to save changes to the data on the FormClosed event Build and run the application

Lab: Accessing Data by Using a DataGridView Control Exercise 1: Binding Data to Controls in a Form (15 minutes)

Lesson 2: Reading and Writing Relational Data Connecting to a Data Source Creating and Running ADO.NET Commands How to Retrieve Data by Using a Data Reader What Is a Data Adapter? How to Fill and Access DataSet Data How to Save a DataSet to a Database Guidelines for Secure Coding with ADO.NET

Connecting to a Data Source Database 1. Import namespaces 2. Create a Connection object 3. Call the Open method to open the connection 4. Call the Close method to close the connection .NET Application

Creating and Running ADO.NET Commands Method Description ExecuteScalar Executes a query and returns a single result ExecuteReader Executes a query and retrieves rows from a data source ExecuteNonQuery Executes a query that performs an action in the database, and returns the number of rows affected

How to Retrieve Data by Using a Data Reader 1 Create a connection object 2 Create a command object and specify an SQL query 3 Open the database connection 4 Invoke the ExecuteReader method and obtain a data reader object 5 Use the data reader object to iterate through the result set 6 Close the database connection .NET Application Database

What Is a Data Adapter? DataSet Database DataAdapter Invoke Fill method to populate DataSet 1 Invoke Update method to merge changes 2 DataSet Database DataTable Object DataAdapter Fill Method Update Method

How to Fill and Access DataSet Data 1 Import required namespaces 2 Create a SqlDataAdapter object 3 Set the SelectCommand property to an SQL query 4 Create a DataSet object 5 Open the database connection 6 Invoke the Fill method 7 Close the database connection

How to Save a DataSet to a Database 1 Import required namespaces 2 Create a SqlDataAdapter object 3 Set the command property to an SQL query 4 Create a DataSet object 5 Open the database connection 6 Invoke the update method 7 Close the database connection

Guidelines for Secure Coding with ADO.NET Do not echo user security credentials when opening a connection Use Windows authentication if possible Store connection strings in the application configuration file Encrypt connection strings Validate user input Prevent SQL injection attacks Stored procedures . . .

Lab: Accessing Data by Using ADO.NET Commands Exercise 1: Creating and Running Simple Commands (30 minutes) Exercise 2: (OPTIONAL) Creating and Running Query Commands (30 minutes)

Lesson 3: Reading and Writing XML Data How to Read and Write a DataSet as XML Data How to Read XML Data by Using XmlReader How to Write XML Data by Using XmlWriter How to Process XML Data by Using the Document Object Model

How to Read and Write a DataSet as XML Data Save a DataSet as XML DiffGram IgnoreSchema WriteSchema Load XML into a DataSet Auto Fragment InferSchema InferTypeSchema ReadSchema DataSet

How to Read XML Data by Using XmlReader 1 Create an XmlReaderSettings object 2 Create an XmlReader object 3 Iterate through the nodes in the XML document 4 Retrieve the value of nodes 5 Close the document

How to Write XML Data by Using XmlWriter 1 Create an XmlWriterSettings object 2 Create an XmlWriter object 3 Write the start of the XML document 4 Write nodes to the XML document 5 Write the end of the XML document

How to Process XML Data by Using the Document Object Model DOM: A standard API for reading and writing XML data Node types include: root, element, child element, and attribute Operations: Read the content of XML data Move randomly around the XML document Add, modify, clone, and delete content in the XML document Create a new XML document

Lab: Reading and Writing XML Data Exercise 1: Reading and Writing a DataSet as XML Data (15 minutes)

Lab Discussion What are the four core data providers in the .NET Framework? What classes can you use to establish a connection to a SQL Server database? What are the advantages and disadvantages of connected and disconnected operations? What are the available options for reading and writing XML data?