connection strings in .NET

What are the standard dot net framework data providers that are shipped with the Dot Net framework 1.1?
The Dot Net Framework 1.1 is shipped with four different data providers:
Dot Net Framework data provider for Microsoft SQL Server DBMS
Dot Net Framework data provider for Oracle DBMS (available only in Framework 1.1)
Dot Net Framework data provider for OLEDB supporting DBMS
Dot Net Framework data provider for ODBC supporting data sources (available only in Framework 1.1)
Why should one use a specialized data provider when the data can be accessed with general data providers?
The specialized data providers (e.g., SQL Server and Oracle) are built specially for a particular kind of DBMS and works much more efficiently than the general data providers (e.g., OLEDB and ODBC). In practice, the specialized data providers are many times efficient than the general data providers.
What is the Dot Net Framework data provider for SQL Server?
The dot net framework data provider for SQL Server is the optimized data provider for Microsoft SQL Server 7 or later. It is recommended to use SQL Server data provider to access the SQL Server DB than general provider like OLEDB. The classes for this provider are present in the System.Data.SqlClient namespace.
What is the Dot Net Framework data provider for Oracle?
The dot net framework data provider for Oracle is the optimized data provider for Oracle DBMS. It is recommended to use Oracle data provider to access the Oracle DB than general provider like OLEDB. It supports the Oracle Client version 8.1.7 and later. The classes for this provider are present in the System.Data.OracleClient namespace. This provider is included in the .Net framework 1.1 and was not available in the Dot Net framework 1.0.
What is the Dot Net Framework data provider for OLEDB?
The dot net framework data provider for OLEDB provides connectivity with the OLEDB supported database management systems. It is the recommended middle tier for the SQL Server 6.5 or earlier and Microsoft Access Database. It is a general data provider. You can also use it to connect with the SQL Server or Oracle Database Management Systems. The classes for this provider are present in the System.Data.OleDBClient namespace.
What is the Dot Net Framework data provider for ODBC?
The dot net framework data provider for ODBC provides connectivity with the ODBC supported database management systems and data sources. It is a general data provider. You can also use it to connect with the SQL Server or Oracle Database Management Systems. The classes for this provider are present in the System.Data.ODBCClient namespace. This provider is included in the .Net framework 1.1 and was not available in the Dot Net framework 1.0.
What are the basic steps involved in data access with ADO.Net in disconnected environment?
Data access using ADO.Net involves the following steps:
>>Defining the connection string for the database server
>>Defining the connection (SqlConnection, OleDbConnection, etc) to the database using the connection string
>>Defining the command (SqlCommand, OleDbCommand, etc) or command string that contains the query
>>Defining the data adapter (SqlDataAdapter, OleDbDataAdapter, etc) using the command string and the connection object
>>Creating a new DataSet object
>>If the command is SELECT, filling the dataset object with the result of the query through the data adapter
>>Reading the records from the DataTables in the datasets using the DataRow and DataColumn objects
>>If the command is UPDATE, INSERT or DELETE, then updating the dataset through the data adapter

>>Accepting to save the changes in the dataset to the database

How do I define a connection string for the database server?
For MS SQL Server, used with the SQL Server data provider, we can write the connection string like:
C# Version

// for Sql Serverstring connectionString = "server=P-III; database=programmersheaven;" +_"uid=sa; pwd=;";
VB.Net Version'

/ for Sql ServerDim

connectionString As String = "server=P-III; database=programmersheaven;" + _ "uid=sa; pwd=;"
First of all we have defined the instance name of the server, which is P-III on my system. Next we defined the name of the database, user id (uid) and password (pwd). Since my SQL server doesn't have a password for the System Administrator (sa) user, I have left it blank in the connection string. (Yes I know this is very dangerous and is really a bad practice - never, ever use a blank password on a system that is accessible over a network)
For Oracle Database Server, used with the Oracle data provider, we can write the connection string like:
C# Version

string connectionString = "Data Source=Oracle8i;User Id=username;" + "Password=pwd; Integrated Security=no;";
VB.Net Version

Dim connectionString As String = "Data Source=Oracle8i;User Id=username;" + _"Password=pwd; Integrated Security=no;"
For MS Access Database, used with the OLE DB data provider, we can write the connection string like:
C# Version

// for MS Accessstring

connectionString = "provider=Microsoft.Jet.OLEDB.4.0;" + "data source = c:\\programmersheaven.mdb";
VB.Net Version

' for MS Access

Dim connectionString As String = "provider=Microsoft.Jet.OLEDB.4.0;" + _ "data source = c:\programmersheaven.mdb"
First we have defined the provider of the access database. Then we have defined the data source which is the address of the target database.
For MS SQL Server, used with the ODBC data provider, we can write the connection string like:
C# Version

string connectionString = "Driver={SQL Server};Server=FARAZ;Database=pubs;Uid=sa;Pwd=;";
VB.Net Version

Dim connectionString As String = "Driver={SQL Server};Server=FARAZ;Database=pubs;Uid=sa;Pwd=;"