Introduction to Ado.net

Before Ado.net we use Ado (Active Database Object) to access data from databae. Basically Ado has automatic driver detection technique and tt has only one drawback that it only provide a connected environment so efficiency of system may decrease.

ADO.NET is a new database technology used by .Net platform (introduced in 2002).Infact it is a set of classes used to communicate between an application front end and a database.It supports both connected & disconnection mode of data access.

Mandatory Namespaces used in ADO.Net

In any .NET data access page, before you connect to a database, you first have to import all the necessary namespaces that will allow you to work with the objects required. Namespaces used in ADO.Net are :

1. System.Data

   It contains the common classes for connecting, fetching data from database. Classes are like as DataTable, DataSet, DataView etc.

2. System.Data.SqlClient

   It contains classes for connecting, fetching data from Sql Server database. Classes are like as SqlDataAdapter,SqlDataReader etc.

3. System.Data.OracleClient

   It contains classes for connecting, fetching data from Oracle database. Classes are like as OracleDataAdapter,OracleDataReader etc.

4. System.Data.OleDb

   It contains classes for connecting, fetching data from any database(like msaccess, db2, oracle, sqlserver, mysql). Classes are like as OleDbDataAdapter,OleDbDataReader etc.

5. System.Data.Odbc

   It contains classes for connecting, fetching data from any database(like msaccess, db2, oracle, sqlserver, mysql). Classes are like as OdbcDataAdapter,OdbcDataReader etc.

Component of ADO.NET architecture

1. Data Provider

   Data provider is a set of ADO.Net classes that allow us to access a database. Basically, it is a bridge between our application (We can say front-end) and data source. There are following Data Provider :
   1. SqlServer Data Provider:-It is used to access data from SqlServer database (for version 7.0 or later).
   2. Oracle Data Provider:-It is used to access data from oracle database (for version 8i or later).
   3. OleDb Data Provider:-It is used to access data from any database (msaccess, mysql, db2).
   4. Odbc Data Provider :-It is used to access data from any database (msaccess, mysql, db2).

2. Data Set

   Basically it is a small Data structure that may contain multiple datatables from multiple sources.The information in dataset is created inform of XML and is stored with .xsd extention.It support disconnected mode of data access.It has both scrolling mode means forward and backward scrolling mode (fetching of data).DataSet can have multiple Datatable from multiple sources but DataReader is able toread only single Datatable.