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How to merge tables in a Dataset - OLEDB Data Source

The DataSet contains copy of the data we requested through the SQL statement. The OleDbDataAdapter object allows us to populate DataTable in a DataSet. We can use Fill method in the OleDbDataAdapter for populating data in a Dataset. We can populate Dataset with more than one table at a time using OleDbDataAdapter Object. The DataTableCollection contains zero or more DataTable objects. In some situation we want to combine the result of multiple SQL query results as a single result set. In that case we can use the Dataset's Merge method for doing this. The tables involved in the merge should be identical. The following VB.NET source code shows how to merge the tables from two different dataset.




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 OleDbDataAdapter
        Dim ds1 As New DataSet
        Dim ds2 As New DataSet
        Dim dt As DataTable
        Dim firstSql As String
        Dim secondSql As String
        Dim i As Integer
        connetionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=Your mdb filename;"
        firstSql = "Your First SQL Statement Here"
        secondSql = "Your Second SQL Statement Here"
        connection = New OleDbConnection(connetionString)
        Try
            connection.Open()
            oledbAdapter = New OleDbDataAdapter(firstSql, connection)
            oledbAdapter.Fill(ds1, "First Table")
            oledbAdapter.SelectCommand.CommandText = secondSql
            oledbAdapter.Fill(ds2, "Second Table")
            oledbAdapter.Dispose()
            connection.Close()

            ds1.Tables(0).Merge(ds2.Tables(0))
            dt = ds1.Tables(0)

            For i = 0 To dt.Rows.Count - 1
                MsgBox(dt.Rows(i).Item(0) & "  --  " & dt.Rows(i).Item(1))
            Next

        Catch ex As Exception
            MsgBox("Can not open connection ! ")
        End Try
    End Sub
End Class

connetionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=Your mdb filename;"
firstSql = "Your First SQL Statement Here"
secondSql = "Your Second SQL Statement Here"

You have to replace the string with your real time variables.





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