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

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

Working with ADO.NET

Working with ADO.NET/Lesson 5/Slide ‹#› 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.



ADO.NET Object Model



ADO.NET Object Model

DATASET

VISUAL BASIC .NET APPLICATION (WINDOWS/ WEB FORM)

DATA PROVIDER

Accessing retrieved data

Accessing retrieved data

CONNECTION

COMMAND

DATA ADAPTER

DATA READER

Establishes connection with the database

Filling dataset with data

Transfers data to the dataset and reflects the changes made in the dataset to the database

DATABASE

Retrieves data in a read-only, forward only modeExecutes a command to retrieve data from the 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



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




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

DataRow DataColumn

DATASET

DataRelationCollection

DataRelation

DataTableCollection

DataTable

DataRowCollection DataColumnCollection

ExtendedProperties

DataView PrimaryKey



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.



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.



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.

Documents

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

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