ADO.NET by ASP.NET Development Company in india

iFour ConsultancyIntroduction to ADO. NET

Introduction to ADO.NET

Data Providers

Classes

SqlConnection Class

SqlCommand Class

SqlDataReader Class

DataSet Class

Connected architecture

Disconnected architecture

3-Tier Architecture

INDEX

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Introduction to ADO.NET : Definition

Object-oriented set of libraries that allows interaction with data sources

Commonly, the data source is a database, but it could also be a text file, an Excelspreadsheet, or an XML file. It has classes and methods to retrieve and manipulate data

It provides a bridge between the front end controls and the back end database

The ADO.NET objects encapsulate all the data access operations and the controlsinteraction with these objects to display data, thus hiding the details of movement of data

•A markup language is a set of markup tags




Introduction to ADO.NET : Data Providers

Provides a relatively common way to interact with data sources, but comes in differentsets of libraries for each way you can talk to a data source

These libraries are called Data Providers and are usually named for the protocol or datasource type they allow you to interact with.

Table shows data providers, the API prefix they use, and the type of data source theyallow you to interact with

Provider Name API prefix Data Source Description

ODBC Data Provider Odbc Data Sources with an ODBC interface. Normally older data bases

OleDb Data Provider OleDb Data Sources that expose an OleDb interface, i.e. Access or Excel

Oracle Data Provider Oracle For Oracle Databases

SQL Data Provider Sql For interacting with Microsoft SQL Server

Borland Data Provider Bdp Generic access to many databases such as Interbase, SQL Server, IBM DB2, and Oracle




SqlConnection Class

SqlCommand Class

SqlDataReader Class

SqlDataAdaptor Class

DataSet Class

Introduction to ADO.NET : Classes




To interact with a database, connection to database is must

The connection helps identify the database server, the database name, user name,password, and other parameters that are required for connecting to the data base

A connection class object is used by command objects to know which database to executethe command

Introduction to ADO.NET : SqlConnection Class




Add Connection String in Web config<connectionStrings>

<add name="ConnectionName" connectionString="Data Source=192.168.0.27\sql2014;Initial Catalog=DatabaseName;Integrated Security=false;UID=username;PWD=Password;" providerName="System.Data.SqlClient" />

</connectionStrings>

Create A Connection ObjectSqlConnection con=new

SqlConnection(ConfigurationManager.ConnectionStrings("ConnectionName").ConnectionString);

con.Open();

// Write Insert/Update/Delete/Select Query

con.Close()

SqlConnection Class - Example




Used to send SQL statements to the database

It uses a connection object to figure out which database to communicate with

The Command class provides methods for storing and executing SQL statements and StoredProcedures. The following are the various commands that are executed by the Command Class ExecuteReader: Returns data to the client as rows. This would typically be an SQL select statement or a

Stored Procedure that contains one or more select statements. This method returns a DataReader objectthat can be used to fill a DataTable object or used directly for printing reports and so forth

ExecuteNonQuery: Executes a command that changes the data in the database, such as an update,delete, or insert statement, or a Stored Procedure that contains one or more of these statements. Thismethod returns an integer that is the number of rows affected by the query

ExecuteScalar: Returns a single value. This kind of query returns a count of rows or a calculated value

ExecuteXMLReader: (SqlClient classes only) Obtains data from an SQL Server 2000 database using an XMLstream. Returns an XML Reader object

Introduction to ADO.NET : SqlCommand Class




Creating a SqlCommand Object

Similar to other C# objects, Instantiate a SqlCommand object via the new instance declaration, as follows:

Querying Data

When using a SQL select command, Retrieve a data set for viewing. To accomplish this with a SqlCommand object,use the ExecuteReader method, which returns a SqlDataReader object. We’ll discuss the SqlDataReader in a futurelesson

The example below shows how to use the SqlCommand object to obtain a SqlDataReader object:

SqlCommand Class – Example




Inserting Data

To insert data into a database, use the ExecuteNonQuery method of the SqlCommand object. The following code shows how to insert data into a database table:

SqlCommand Class – Example (Cont.)




Updating Data

The ExecuteNonQuery method is also used for updating data. The following code shows how to update data:





Deleting Data

Delete data using the ExecuteNonQuery method. The following example shows how to delete a record from a database with the ExecuteNonQuery method:





Getting Single values

Sometimes need single value from database, which could be a count, sum, average, or other aggregated value from a data set

Performing an ExecuteReader and calculating the result in code is not the most efficient way to do this

The following example shows how to do this with the ExecuteScalar method:





Many data operations require reading only a stream of data

This object allow to obtain the results of a SELECT statement from a command object

For performance reasons, the data returned from a data reader is a fast forward-onlystream of data

This means pull the data from the stream in a sequential manner This is good for speed,but if need for manipulating data, then a DataSet is a better object to work with

Introduction to ADO.NET : SqlDataReader Class




Creating a SqlDataReader Object

Getting an instance of a SqlDataReader is a little different than the way other ADO.NET objectsare initialized. Call ExecuteReader on a command object, like this:

The ExecuteReader method of the SqlCommand object, cmd , returns a SqlDataReader instance

Creating a SqlDataReader with the new operator doesn’t do anything

The SqlCommand object references the connection and the SQL statement necessary for theSqlDataReader to obtain data

SqlDataReader Class - Example




Reading Data

The typical method of reading from the data stream returned by the SqlDataReader is to iterate through each row with a while loop. The following code shows how to accomplish this:

SqlDataReader Class – Example (Cont.)




The data adapter makes it easy to accomplish these things by helping to manage data in adisconnected mode

The data adapter fills a DataSet object when reading the data and writes in a single batch whenpersisting changes back to the database

A data adapter contains a reference to the connection object and opens and closes the connectionautomatically when reading from or writing to the database

The data adapter contains command object references for SELECT, INSERT, UPDATE, and DELETEoperations on the data

Data adapter defined for each table in a DataSet and it will take care of all communication with thedatabase

Introduction to ADO.NET : SqlDataAdaptor Class




Creating A SqlDataAdapter

It holds the SQL commands and connection object for reading and writing data

The code above creates a new SqlDataAdapter, daCustomers. The SQL select statement specifieswhat data will be read into a DataSet

The connection object, conn, should have already been instantiated, but not opened

SqlDataAdapter’s responsibility to open and close the connection during Fill and Update methodcalls

SqlDataAdaptor Class - Example




DataSet objects are in-memory representations of data

Contains multiple Datatable objects, which contain columns and rows, just like normaldatabase tables. Possible to define relations between tables to create parent-childrelationships

Specifically designed to help manage data in memory and to support disconnectedoperations on data, when such a scenario makes sense

An object that is used by all of the Data Providers, which is why it does not have a DataProvider specific prefix

Introduction to ADO.NET : DataSet Class




Creating a DataSet Object

There isn’t anything special about instantiating a DataSet. Create a new instance, just like any other object:

Filling the DataSet

Fill method of the SqlDataAdapter:

The Fill method, in the code above, takes two parameters: a DataSet and a table name

The DataSet must be instantiated before trying to fill it with data. The second parameter is the name of the table thatwill be created in the DataSet

Its purpose is to identify the table with a meaningful name later on. Typically, same name as the database table istaken. However, if the SqlDataAdapter’s select command contains a join, need to find another meaningful name.

DataSet Class - Example




The architecture of ADO.net, in which connection must be opened to access the dataretrieved from database is called as connected architecture

Built on the classes connection, command, datareader and transaction

This creates more traffic to the database but is normally much faster for doing smallertransactions

Example:

Introduction to ADO.NET : Connected architecture

Database

Web Form




The architecture of ADO.net in which data retrieved from database can be accessed even when connection to database was closed is called as disconnected architecture

Built on classes connection, dataadapter, commandbuilder and dataset and dataview

Method of retrieving a record set from the database and storing it giving the ability to do many CRUD (Create, Read, Update and Delete) operations on the data in memory, then it can be re-synchronized with the database when reconnecting

Example:

Introduction to ADO.NET : Disconnected architecture

Database

Web Form

Data Adapter




A layer is a reusable portion of code that performs a specific function

This specific layer is in charge of working with other layers to perform some specific goal Data Layer

It contains methods that helps the Business Layer to connect the data and perform required actions, whether to return data or to manipulate data (insert, update, delete)

Business Layer A BAL contains business logic, validations or calculations related to the data. Though a website could talk to the

data access layer directly, it usually goes through another layer called the Business Layer. This ensures the data input is correct before proceeding, and can often ensure that the outputs are correct as well

Presentation Layer Contains pages like .aspx or Windows Forms where data is presented to the user or input is taken from the user. The ASP.NET website or Windows Forms application (the UI for the project) is called the Presentation Layer. This is

the most important layer simply because it’s the one that everyone sees and uses Even with a well structured business and data layer, if the Presentation Layer is designed poorly, this gives the users

a poor view of the system

Introduction to ADO.NET : 3-Tier Architecture




Graphical representation of 3-Tier Architecture

Introduction to ADO.NET : 3-Tier Architecture Example

UIAsp.net

MVC

E.g.:a=20;B=10;

Store c;

BLLC#.net

E.g.:c=a+b;

DALADO.NET

E.g.:Output

c;

DatabaseE.g.: Ms Sqlserver

Presentation Layer also called User

Interface. Computer, Mobile phone,etc.

Business Logic LayerDoes all the logic

operations

Data Access LayerCommunicate with

the database




https://www.tutorialspoint.com/asp.net/asp.net_ado_net.htm https://msdn.microsoft.com/en-us/library/27y4ybxw(v=vs.110).aspx http://csharp-station.com/Tutorial/AdoDotNet https://msdn.microsoft.com/en-us/library/h43ks021(v=vs.110).aspx

References




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