The DataReader Object

We can use a DataReader object to read data from a database. A DataReader object is effectively a forward-only collection of records from your data source.

OleDbDataReader dbReader = null;
OleDbCommand cmd = Myconnection.CreateCommand();

cmd.CommandText = "SELECT * FROM familyTree";
dbReader = cmd.ExecuteReader();


while(dbReader.Read())
{
Email = (string)dbReader.GetValue(5);
lb.Items.Add(Email);
}

map Data Access in .NET

using Datasets in .net

Creating a DataSet

Using VB.Net

Dim ds As New DataSet("DataSetName")
Console.WriteLine(ds.DataSetName)

Using C#.Net

DataSet ds = new DataSet("DataSetName");
Console.WriteLine(ds.DataSetName);

Filling the DataSet Object

Using VB.Net

Dim strConn, strSQL As String
strConn = "Provider=SQLOLEDB;Data Source=(local)NetSDK;" & _
"Initial Catalog=Northwind;Trusted_Connection=Yes;"
strSQL = "SELECT CustomerID, CompanyName, ContactName, Phone " & _
"FROM Customers"
Dim da As New OleDbDataAdapter(strSQL, strConn)
Dim ds As New DataSet()
da.Fill(ds, "Customers")

Using C#.Net

string strConn, strSQL;
strConn = "Provider=SQLOLEDB;Data Source=(local)\NetSDK;" +
"Initial Catalog=Northwind;Trusted_Connection=Yes;";
strSQL = "SELECT CustomerID, CompanyName, ContactName, Phone " +
"FROM Customers";
OleDbDataAdapter da = new OleDbDataAdapter(strSQL, strConn);
DataSet ds = new DataSet();
da.Fill(ds, "Customers");