Chapter 5 Configuring Connections and Connecting to Data

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Chapter 5
Configuring Connections and
Connecting to Data
Week ?
Chapter 5

Lesson 0: ADO.NET introduce

Lesson 1: Creating and Configuring
Connection Objects

Lesson 2: Connecting to Data Using
Connection Objects

Lesson 3: Working with Connection Pools

Lesson 4: Handling Connection Errors

Lesson 5: Enumerating the Available SQL
Servers on a Network
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Overview of ADO.NET
with the .NET Framework
Introdution to ADO.NET
Introdution to ADO.NET
Universal Data Access (UDA)

Microsoft’s strategy for accessing data for
multiple providers


Goal is to access any type of data from any
application on any type of computer
Introdution to ADO.NET
Introdution to ADO.NET
3
OLEDB

Technology designed to implement the UDA
concept

Provides an standardized object-oriented
interface

Allows access data from any source

Library functions

Hard to use
Introdution to ADO.NET
Introdution to ADO.NET
ADO.NET

Important Core of the .NET Framework

Microsoft’s latest database object model

Data access solution in .NET

Allows VB programmers to use a standard
set of objects to refer to data from any

source: SQL Server, Oracle, OLE DB &
ODBC (UDA…)
ActiveX Data Objects 

 ADO
ActiveX Data Objects 

 ADO
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Power of ADO.NET

.NET framework is integrated with XML, stored and transferred in
XML

Can save and load from XML

XML is the way to exchange data between business

any programming language use it.

Create XML Schema

Good use in multitier applications

Disconnected dataset
Introdution to ADO.NET
Introdution to ADO.NET
XML is an industry standard
format for storing and
transferring data over

multiple platforms.
XML is an industry standard
format for storing and
transferring data over
multiple platforms.
ADO.NET and XML

Working together in n-tier architech
Introdution to ADO.NET
Introdution to ADO.NET
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.NET Data Provider Objects
SelectCommand
InsertCommand
UpdateCommand
DeleteCommand
Connection
.NET Data Provider
Command
Data Adapter
DataReader
Generic classes

Connection

Command.

DataReader

DataAdapter


DataSet

Core ADO.NET Namespaces
System.Data
System.Data.OleDb
System.Data.SqlClient
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Importing the ADO.NET
Namespaces
Needed to build a data access application

For OLE DB: (MS Access)
Imports System.Data
Imports System.Data.OleDB

For SQL Server:
Imports System.Data
Imports System.Data.SQLClient
Lesson 1: Creating and Configuring Connection
Objects

What Is a Connection Object?
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What Is a Connection Object?
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Connection classes
How to create connection?

Creating Connections in Server Explorer


Lab: P206

Creating Connections Using Data Wizards

Lab: P207

Creating Connection Objects
Programmatically

(see next page)
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How to create connection?

Creating Connection Objects
Programmatically (page 204-205)
Connection properties
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Connection methods
And … Questions?
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Lesson 2: Connecting to Data Using
Connection Objects

Opening and Closing Data Connections

Connection Events
Opening and Closing Data
Connections


Open and Close methods.

Connection must contain a valid connection
string.

State of the connection change
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Connection Events
Connection open and close method

Where?

When
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Exer: Open and Close methods.

Lab page 213

Questions

Connect to SQL Server

Connect to MS Access
Lesson 3: Working with Connection
Pools

What Is Connection Pooling?

Controlling Connection Pooling Options


Configuring Connections to Use Connection
Pooling
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What Is Connection Pooling?

Reuse of existing connections

Reduce the overhead when creating and
disposing of connections

Connections have the same configuration

Each time call SqlConnection.Open with a
unique connection string, a new pool is
created
Controlling Connection Pooling
Options

is enabled by default when creating
ADO.NET connection

set Pooling=False in your connection string

Connection Pooling Connection String
Keywords (Page 227)

Min Pool Size, Max Pool Size
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Configuring Connections to Use
Connection Pooling (page 229)


Configuring Connection Pooling with SQL Server
Connections

Manual config

Data Source=SqlServerName;Initial
Catalog=DatabaseName; Integrated Security=True;Min
Pool Size=5

Configuring Connection Pooling with OLE DB
Connections

Automatic by Provider

Provider=Microsoft.Jet.OLEDB.4.0;Data
Source=C:\DataSources\Nwind.mdb;OLE DB Services=-1

(See page 229)

DEMO POOL with SQLSERVER
Lesson 4: Handling Connection Errors

Handle exceptions when connecting to a
database.

Use the SqlException (OLEDBException)
class to detect connection errors

Use the SqlError (OleDBError) class to detect

connection errors.
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Error collections

SQL Server returns error, the Data Provider
for SQL Server throws a SqlException that
you can catch in your application
When SqlException is thrown, inspect the
SqlException.Errors collection of errors
Error collections (page 233)
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Exer:

Lab page 232
Lesson 5: Enumerating the Available SQL
Servers on a Network

Using Instance property of the
SqlDataSourceEnumerator class
call the GetDataSources method.

The GetDataSources method returns a Data-
Table that contains information for each SQL
server that is visible on the network.
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Enumerating the Available SQL
(page 237)
Enumerating the Available SQL

Lab page 238

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And … Questions?
And … Questions?

What about?

UDA

OLEDB

DAO, ADO and ADO.NET

Connection

ConnectionPool

ConnectionString

What informations in Connection data object?