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Working with ADO.NET

Objectives
In this lesson, you will learn to:
Identify the need for ADO.NET
Identify the features of ADO.NET
Identify the components of the ADO.NET object model
Connect to a database by creating a data adapter
Access a database through a dataset
Preview the data adapter result

©NIIT Working with ADO.NET/Lesson 5/Slide 1 of 30


ADO.NET
Is a model used by Visual Basic .NET applications to
communicate with a database for retrieving, accessing, and
updating data.
Uses a structured process flow to interact with a database.



Features of ADO.NET
Disconnected data architecture — Applications connect to
the database only while retrieving and updating data.
Data cached in datasets — ADO.NET is based on a
disconnected data structure. Therefore, the data is retrieved
and stored in datasets.
Data transfer in XML format — ADO.NET uses XML for
transferring information from a database into a dataset and
from the dataset to another component.
Interaction with the database is done through data
commands.



Just a Minute…
List the features of ADO.NET.



ADO.NET Object Model

DATA PROVIDER

Establishes
connection with
the database
CONNECTION
Retrieves data in a
VISUAL Accessing read-only,
BASIC .NET retrieved data forward only mode
APPLICATION DATA READER
(WINDOWS/ Executes a
WEB FORM) command to retrieve
data from the DATABASE

COMMAND database

Accessing retrieved Transfers data to
data the dataset and
reflects the
Filling dataset with changes made in
data the dataset to the
DATASET
DATA ADAPTER database



ADO.NET Object Model (Contd.)
Data from a database can be assessed through:
A dataset
A DataReader object



Key Components of the ADO.NET Model
Data Provider
Is used for connecting to a database, retrieving data,
and storing the data.
Is of two types:
® OLE DB data provider
® SQL Server data provider



Just a Minute…
Identify the two types of data providers and list the difference
between them.



Components of a Data Provider
Connection
Used to establish a connection with a data source
Some commonly used properties and methods:
® ConnectionString property
® Open()method

® Close()method

® State property



Components of a Data Provider (Contd.)
Data adapter
Creates a dataset and updates the database.
Handles data transfer between the database and the
dataset through its properties and methods.
Displays the data through the process of table mapping.
Are of two types:
® SqlDataAdapter

® OleDbDataAdapter



Just a Minute…
What is the function of a data adapter?



Data command
Is a SQL statement or a stored procedure that is used to
retrieve, insert, delete, or modify data from a data
source.
Is an object of the OleDbCommand or SQLCommand
class.



Data reader
Is used to retrieve data from a data source in a
read-only and forward-only mode.
Stores a single row at a time in the memory.
Commonly used methods:
® Read()

® Close()

® NextResult()



Dataset
Is a disconnected, cached set of records that are retrieved
from a database.
Is present as a DataSet class in the System.Data
namespace.
Has its own object model.



Dataset Object Model

DATASET

DataRelationCollection DataTableCollection ExtendedProperties

DataRelation DataTable

DataRowCollection DataView PrimaryKey DataColumnCollection

DataRow DataColumn



Just a Minute…
What are the various components of a dataset?



Problem Statement 5.D.1
The call center application needs to provide the facility of
viewing the customer details for the Sales department.



Task List
Identify the data that needs to be displayed.
Identify the method for creating a data adapter.
Identify the type of dataset to be created.
Create a data adapter.
Create a dataset.
Preview the database records.



Task 1: Identify the data that needs to be displayed.
Result:
As per the given problem statement, the data to be
displayed is as follows:
CustID
FName
LName
Address
Phone
email



Task 2: Identify the method for creating a data
adapter.
There are three methods to create a data adapter:
Manually
Through a wizard
Using the Server Explorer window
Result:
In the given problem statement, you will create a data
adapter by using Data Adapter Configuration Wizard since it
lets you create a data adapter with minimum steps.



Just a Minute…
What are the different methods of creating a data adapter?



Task 3: Identify the type of dataset to be created.
Datasets are of two types:
Typed
Untyped
Typed dataset
Is derived from the DataSet class and has an
associated XML schema, which is created at the time of
the creation of the dataset.
Can be customized after creation.
Supports Intellisense and auto‑completion for the
elements of the syntax while writing code.



Task 3: Identify the type of dataset to be created.
(Contd.)
Untyped dataset
Does not have any associated XML schema, therefore,
the structure of an untyped dataset is not known at the
compile time.
Represents tables and columns as collections.
Does not support Intellisense and auto‑completion for
the elements of the syntax.
Result:
Since the structure of the data is known at compile time,
you will create a typed dataset for the given problem
statement.



Just a Minute…
What is the difference between typed and untyped dataset?



Task 4: Create a data adapter.
Task 5: Create a dataset.
Task 6: Preview the database records.



Problem Statement 5.P.1
An application needs to be created that allows the Diaz
Telecommunications Sales Manager to preview the customer
order details from the database. In addition, for each order,
percentage of the cost of a product given as advance needs to
be previewed.



Summary
In this lesson, you learned that:
ADO.NET is a data access programming model for
accessing the data stored in a database from a .NET
application.
ADO.NET has the following features:
A disconnected data architecture
Data cached in datasets
The use of XML format for data transfer
Database operations done through data commands



Summary (Contd.)
ADO.NET consists of the following components:
Data Provider — Used for connecting to a database,
retrieving data, storing the data in a dataset, and
updating the database.
Data Adapter — A data adapter is integral to the
working of the ADO.NET model since data transfer to
and from the database is done through a data adapter.
Dataset — A dataset is a disconnected cached set of
records that are retrieved from the database.
A data adapter communicates with a database through data
commands. These data commands use parameters for
execution.


Summary (Contd.)
After a dataset has been created, a data adapter uses the
process of table mapping to map the columns in the
database table with the dataset columns.
A data adapter can be created by using any of the following
methods:
Manually
Through a wizard
By using Server Explorer



Summary (Contd.)
Datasets are of two types:
Typed datasets – A typed dataset is derived from the
DataSet class and has an associated schema.
Untyped datasets – An untyped dataset does not have
any associated XML schema. The tables and columns
in an untyped dataset are represented as collections.


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