1. Working with ADO.NET
Objectives
In this lesson, you will learn to:
• 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 Creating Data Centric Applications using Lesson 1A / Slide 1 of 18
ADO.NET

2. Working with ADO.NET
An Introduction to ADO.NET
• Applications need to communicate with a database for the following tasks:
• Retrieving the data stored in the database and presenting it in a user-
friendly format
• Updating the database, that is, inserting, modifying, and deleting data
• ADO.NET is a model used by .NET applications to communicate with a
database for retrieving, accessing, and updating data.
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 2 of 18
ADO.NET

3. Working with ADO.NET
Features of ADO.NET
• Disconnected data architecture :
• Applications connect to the database only while retrieving and updating
data.
• A database can cater to the needs of several applications simultaneously
since the interaction is for a shorter duration.
• Data cached in datasets :
• A dataset is the most common method of accessing data in ADO.NET.
• A dataset is a cached set of database records.
• A dataset is independent of data source and you remain disconnected from
the data source.
• Scalability
• Database operations are performed on the dataset instead of on the
database, therefore, database can meet the increasing demands of users
more efficiently.
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 3 of 18
ADO.NET

4. Working with ADO.NET
Features of ADO.NET (Contd.)
• Data transfer in XML format
• Data is transferred from a database into a dataset and from the dataset to
another component by using XML.
• You can transmit a dataset between different types of applications that
support XML.
• Interaction with the database is done through data commands:
• A DataCommand object can be used for accessing or updating the data
using either a SQL statement or a stored procedure.
• You can retrieve, insert, delete, or modify data from a database by
executing data commands.
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 4 of 18
ADO.NET

5. Working with ADO.NET
The ADO.NET Object Model
• The structured process flow or the object model is shown in the following
figure:
DATA PROVIDER
Establishes
connection with the
database
CONNECTION
Retrieves data in a
VISUAL BASIC Accessing read-only, forward
.NET retrieved data only mode
APPLICATION DATA READER
Executes a command to DATABASE
(WINDOWS/ WEB
retrieve data from the
FORM)
database
COMMAND
Transfers data to the
dataset and reflects
Accessing retrieved data the changes made in
the dataset to the
Filling dataset with data database
DATASET DATA ADAPTER
The ADO.NET Object Model
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 5 of 18
ADO.NET

6. Working with ADO.NET
The ADO.NET Object Model (Contd.)
• The data residing in a database is retrieved through data provider.
• An application can access data either through a dataset or through a
DataReader object:
• Using a dataset: The data is cached in a dataset and the application
accesses the data from the dataset.
• Using a data reader: A DataReader object, which is a component of the
data provider, uses the Connection object to connect to the database.
• The key components of the ADO.NET are as follows:
• Data Provider
• Dataset
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 6 of 18
ADO.NET

7. Working with ADO.NET
Data Provider
• A data provider is used for connecting to a database, retrieving data, storing
the data in a dataset, reading the retrieved data, and updating the database.
• There are two types of data providers:
• OLE DB data provider : Works with all the OLE DB providers, such as SQL
OLE DB provider, Oracle OLE DB provider, and Jet OLE DB provider.
• SQL Server data provider : Is used to work specifically with Microsoft SQL
Server.
Connection
• Used to establish a connection with a data source
• Two of the most common Connection objects used are OleDbConnection and
SqlConnection.
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 7 of 18
ADO.NET

8. Working with ADO.NET
Data Adapter
• Data is transferred to and from a database through a data adapter.
• The changes in the database are actually done by the data adapter.
• You access data from a database by configuring a data adapter.
• Two widely used data adapter are:
• SqlDataAdapter : Configured to access data specifically from Microsoft SQL
Server
• OleDbDataAdapter : Configured to access data from any database that is
supported by an OLE DB data provider
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 8 of 18
ADO.NET

9. Working with ADO.NET
Data Adapter (Contd.)
Properties and Methods
• SelectCommand : Refers to a SQL statement or a stored procedure to retrieve
data from the database
• InsertCommand : Refers to a data command to insert data into a database
• UpdateCommand : Refers to a data command to update a database
• DeleteCommand : Refers to a data command to delete data from a database
• Fill() Method : Fills the dataset with the records from a database
• Update() Method : Executes the corresponding InsertCommand,
UpdateCommand, or DeleteCommand
Creating a data adapter
• There are three methods to create a data adapter:
• Through a wizard
• Using the Server Explorer window
• Programmatically
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 9 of 18
ADO.NET

10. Working with ADO.NET
Data Command and Data Reader
Data Command
• An object representing a SQL statement or a stored procedure that is used to
retrieve, insert, delete, or modify data in a data source
• Derived from the OleDbCommand class
Data Reader
• Used to retrieve data from a data source in a read-only and forward-only mode
• A data reader uses :
• Connection object to connect to the database
• Command object to execute SQL statements or procedures
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 10 of 18
ADO.NET

11. Working with ADO.NET
Dataset
• Dataset is a disconnected, cached set of records that are retrieved from a
database
• dataset object model
DATASET
dataRelationCollection dataTableCollection extendedproperties
DataRelation
DataTable
dataRowCollection dataview primarykey dataColumnCollection
DataRow DataColumn
The Dataset Object Model
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 11 of 18
ADO.NET

12. Working with ADO.NET
Dataset ( Contd.)
Types of Dataset
• Two types of datasets :
• Typed : Has an associated XML schema. XML Schema Definition (XSD)
language is used to define the elements and attributes of XML
documents.
• Untyped : Does not have any associated XML schema. The tables and
columns are represented as collections.
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 12 of 18
ADO.NET

13. Working with ADO.NET
Demo
Connecting to a Database
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 13 of 18
ADO.NET

14. Working with ADO.NET
Problem Statement
• The call center application needs to provide the facility of viewing the customer
details for the Sales department.
• Create an application to display the customer details for the Sales
department.
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 14 of 18
ADO.NET

15. Working with ADO.NET
Solution
• To design the application, you need to perform the following steps:
1. Create a data adapter.
2. Create a data set.
3. Preview the database records.
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 15 of 18
ADO.NET

16. Working with ADO.NET
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.
• The main features of ADO.NET:
• Disconnected data architecture
• Data cached in datasets
• Data transfer in XML format
• Interaction with the database through data commands
• The ADO.NET object model consists of Dataset, Data Provider, and Database.
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 16 of 18
ADO.NET

17. Working with ADO.NET
Summary (Contd.)
• Data provider is used for connecting to a database, retrieving data, storing
the data in a dataset, reading the retrieved data, and updating the database.
Types of data provider are:
• SQL Data Provider
• OLE DB Data Provider
• Oracle Data Provider
• ODBC Data Provider
• Connection object is used to establish a connection with a data source.
• Data adapter is used to transfer data to and from a database. Two types of
Data adapters are:
• SqlDataAdapter
• OleDbDataAdapter
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 17 of 18
ADO.NET

18. Working with ADO.NET
Summary (Contd.)
• Three methods of creating Data adapter are:
• Through a wizard
• Using the Server Explorer window
• Programmatically
• Data command is a object representing a SQL statement or a stored
procedure that is used to retrieve, insert, delete, or modify data in a data
source.
• Data reader is used to retrieve data from a data source in a read-only and
forward-only mode.
• Data is retrieved through datasets. Datasets are of two types i.e. Typed and
Untyped.
• Typed datasets — A typed dataset is derived from the base DataSet
class and has an associated XML 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.
©NIIT Creating Data Centric Applications using Lesson 1A / Slide 18 of 18
ADO.NET