Transcript Module 3: Using ADO.NET to Access Data

Module 3: Using
ADO.NET to Access
Data
Overview

Overview of ADO.NET

Connecting to a Data Source

Accessing Data with DataSets

Using Stored Procedures

Accessing Data with DataReaders

Binding to XML Data
 Overview of ADO.NET

The ADO.NET Object Model

Animation: Using ADO.NET to Access Data

RecordSets vs. DataSets

Using Namespaces
The ADO.NET Object Model
.ASPX Page
DataReader
Command
Company:
Northwind Traders
Database
Connection
DataSetCommand
DataView
DataSet
.ASPX Page
List-Bound
Control
Animation: Using ADO.NET to Access Data
RecordSets vs. DataSets

Recordset

DataSet

One Table

Multiple Tables

Based on Join

Includes Relationship

Move Row by Row

Navigate via Relationship

Disconnected
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Transmit XML File


Connected or
Disconnected
COM Marshalling
Using Namespaces

Use the Import Construct to Declare Namespaces
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.SQL" %>

Namespaces Used with ADO.NET Include:

System.Data

System.Data.ADO

System.Data.SQL

System.Data.XML

System.Data.SQLTypes
Connecting to a Data Source

Using SQLConnection
Dim strConn As String = _
"server=localhost; uid=sa;pwd=; database=northwind"
Dim conn As SQLConnection = New SQLConnection(strConn)

Using ADOConnection
Dim strConn As String = "Provider= SQLOLEDB.1; " & _
"Data Source=localhost; uid=sa; pwd=; " & _
"InitialCatalog=northwind;"
Dim conn As ADOConnection = New ADOConnection(strConn)
 Accessing Data with DataSets

Using DataSets to Read Data

Storing Multiple Tables in a DataSet

Using DataViews

Displaying Data in the DataGrid Control
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Demonstration: Displaying Data in a DataGrid

Using Templates
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Using the Repeater Control

Demonstration: Displaying Data in a Repeater Control
Using DataSets to Read Data

Create the Database Connection

Store the Query in a DataSetCommand
Dim cmdAuthors As SQLDataSetCommand
cmdAuthors = New SQLDataSetCommand _
("select * from Authors", conn)

Create and Populate the DataSet with DataTables
Dim ds As DataSet
ds = New DataSet()
cmdAuthors.FillDataSet(ds, "Authors")
Storing Multiple Tables in a DataSet

Add the First Table
command = New SQLDataSetCommand _
("select * from Authors", conn)
command.FillDataSet(ds, "Authors")
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Add the Subsequent Table(s)
command.SelectCommand = New SQLCommand _
("select * from Books", conn)
command.FillDataSet(ds, "Books")
Books
DataSet
Authors
Data Tables
Using DataViews

DataViews Can be Customized to Present a Subset of
Data from a DataTable

The DefaultView Property Returns the Default DataView
for the Table
Dim dv as DataView
dv = ds.Tables("Authors").DefaultView

Setting Up a Different View of a DataSet
Dim dv as DataView
dv = New DataView (ds.Tables("Authors"))
dv.RowFilter = "state = 'CA'"
Displaying Data in the DataGrid Control

Create the Control
<asp:DataGrid id="dgAuthors" runat="server" />
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Bind to a DataView
dgAuthors.DataSource=ds.Tables("Authors").DefaultView
dgAuthors.DataBind()
Demonstration: Displaying Data in a DataGrid
Using Templates
HeaderTemplate
ItemTemplate
SeparatorTemplate
AlternatingItemT
emplate
FooterTemplate
Using the Repeater Control
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Create the Control and Bind to a DataView
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Display Data in Templated Elements
<asp:Repeater id="repList" runat="server">
<template name="ItemTemplate">
<%# Container.DataItem("au_lname") %>
</template>
</asp:Repeater>
Demonstration: Displaying Data in a Repeater Control
Using Stored Procedures

Calling Stored Procedures
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Passing Parameters

Calling Action Stored Procedures
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Demonstration: Calling Stored Procedures
Calling Stored Procedures
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Stored Procedures Provide Security for Database

Set up the DataSetCommand
Dim cmd as SQLDataSetCommand
cmd = New SQLDataSetCommand()
With cmd.SelectCommand
.ActiveConnection = conn
.CommandText = "ProductCategoryList"
.CommandType = CommandType.StoredProcedure
End With

Run the Stored Procedure and Store Returned Records
cmd.FillDataSet(ds, "Categories")
Passing Parameters

Create Parameter, Set Direction and Value, Add to the
Parameters Collection
workParam = New SQLParameter("@CategoryID", _
SQLDataType.Int)
workParam.Direction = ParameterDirection.Input
workParam.Value = CInt(txtCatID.Text)
cmd.SelectCommand.Parameters.Add (workParam)

Run Stored Procedure
ds = new DataSet()
cmd.FillDataSet(ds, "Products")
Calling Action Stored Procedures
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Use SQLCommand Object
Dim myCmd As SQLCommand = New SQLCommand _
("OrdersCount", conn)
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Call the ExecuteNonQuery Method
conn.Open()
myCmd.ExecuteNonQuery()
conn.Close()

Retrieve Output Parameters
curSales = myCmd.Parameters("@ItemCount").Value
Demonstration: Calling Stored Procedures
Lab 3: Using ADO.NET to Access Data
 Accessing Data with DataReaders

Creating a DataReader
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Reading Data from a DataReader
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Demonstration: Accessing Data Using DataReaders

Using DataSets vs. DataReaders
Creating a DataReader

Create and Open the Database Connection
Dim conn As SQLConnection = New SQLConnection _
("server=localhost;uid=sa;pwd=;database=pubs")
conn.Open()

Create the DataReader From a Command Object
Dim cmdAuthors As SQLCommand = New SQLCommand _
("select * from Authors", conn)
Dim dr As SQLDataReader
cmdAuthors.Execute(dr)

Close the Connection
Reading Data from a DataReader
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Call Read for Each Record


Call Get for Each Field


Returns false when there are no more records
Parameter is the ordinal position of the field
Call Close to Free Up the Connection
myReader.Read()
lblName.Text = myReader.GetString(1) + ", " + _
myReader.GetString(2)
myReader.Close()
Demonstration: Accessing Data Using DataReaders
Using DataSets vs. DataReaders
DataSet
1.
Create a database
connection
DataReader
1.
Create a database connection
2.
Open the database connection
3.
Store query in Command
2.
Store query in
DataSetCommand
3.
Populate DataSet with
FillDataSet method
4.
Populate DataReader with
Execute method
4.
Create DataView
5.
5.
Bind DataView to list-bound
control
Call Read for each record, and
Get for each field
6.
Manually display data
7.
Close the DataReader and the
connection
 Binding to XML Data

Overview of XML

Reading XML Data into a DataSet
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Demonstration: Reading XML Data into a DataSet
Overview of XML
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Machine-Readable and Human-Readable Data
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Defines the Data Content and Structure
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Separates Structure From Presentation
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Allows You to Define Your Own Tags and Attributes
<employee>
<name>Jake</name>
<salary>25000</salary>
<region>Ohio</region>
</employee>
Reading XML Data into a DataSet
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Read the XML File
fs = New FileStream _
(Server.MapPath("schemadata.xml"), _
FileMode.Open, FileAccess.Read)

Read the Contents of the File Stream
Reader = New StreamReader(fs)
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Read Data From the StreamReader into a DataSet
ds.ReadXml(Reader)
Demonstration: Reading XML Data into a DataSet
Review

Overview of ADO.NET

Connecting to a Data Source

Accessing Data with DataSets

Using Stored Procedures

Accessing Data with DataReaders

Binding to XML Data