Dataadapter SelectCommand - OLEDB Data Source

OleDbDataAdapter, a fundamental component of the ADO.NET Data Provider, facilitates the interaction between the Dataset and the Data Source by leveraging the capabilities of the OleDbConnection Object. Its primary role is to establish effective communication between these entities, enabling efficient data retrieval.

A notable feature of the OleDbDataAdapter is its ability to work seamlessly with the DataSet, providing a disconnected data retrieval mechanism. This means that the OleDbDataAdapter retrieves data from the Data Source and populates the DataSet, allowing subsequent data access and manipulation without requiring a continuous connection to the Data Source.

The SelectCommand property of the OleDbDataAdapter plays a vital role in this process. It represents a Command object responsible for retrieving data from the Data Source. By assigning a valid SQL query or stored procedure to the SelectCommand property, the OleDbDataAdapter executes the command and retrieves the corresponding data from the Data Source.

Consider the following program, which demonstrates the usage of the OleDbDataAdapter's SelectCommand property to retrieve data from a Data Source:

Full Source VB.NET
Imports System.Data.OleDb Public Class Form1 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim connetionString As String Dim connection As OleDbConnection Dim oledbAdapter As New OleDbDataAdapter Dim ds As New DataSet Dim i As Integer connetionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=Your mdb filename;" connection = New OleDbConnection(connetionString) Try connection.Open() oledbAdapter.SelectCommand = New OleDbCommand("Your SQL Statement Here", connection) oledbAdapter.Fill(ds) oledbAdapter.Dispose() connection.Close() For i = 0 To ds.Tables(0).Rows.Count - 1 MsgBox(ds.Tables(0).Rows(i).Item(0)) Next Catch ex As Exception MsgBox(ex.ToString) End Try End Sub End Class

The program demonstrates how to access and manipulate the retrieved data within the program by iterating over the DataTable's rows and performing desired operations.