vb.net – Adding the columns from the datatable to the database

I filled in the data with datatable from excel file.
After filling in the data, I want to save the data to the database.
The problem is as follows:
Firstly, the excel columns take fixed names {“cola”,”colb”,”colc”,”cold”,”cole”,”colf”}, and they are 5 columns at a maximum, and they can be 3 or 2 or 4 or 1 .
columns are not specified.
How do I add data in Database, where is If the column does not exist in the DataTable value “-” and if it exists, then it takes its normal value after compared to the constant name of the column.
In order to determine the place of the addition
my try not work

 For i = 1 To dt2.Rows.Count - 1
                            If dt2 Is Nothing Then
                                Exit For : Exit Sub

                            End If


                            Dim com As New OleDbCommand("INSERT INTO EXPORT_TB(EXPORT_a,EXPORT_b,EXPORT_c,EXPORT_d,EXPORT_e) VALUES (@EXPORT_a,@EXPORT_b,@EXPORT_c,@EXPORT_d,@EXPORT_e)", con)
                            '                   
                            com.Parameters.AddWithValue("@EXPORT_a", OleDbType.VarChar).Value = dt2.Rows(i).Item(0).ToString
                            com.Parameters.AddWithValue("@EXPORT_b", OleDbType.VarChar).Value = dt2.Rows(i).Item(1).ToString
                            com.Parameters.AddWithValue("@EXPORT_c", OleDbType.VarChar).Value = dt2.Rows(i).Item(2).ToString
                            com.Parameters.AddWithValue("@EXPORT_d", OleDbType.VarChar).Value = dt2.Rows(i).Item(3).ToString
                            com.Parameters.AddWithValue("@EXPORT_e", OleDbType.VarChar).Value = dt2.Rows(i).Item(4).ToString
                            con.Open()
                            com.ExecuteNonQuery()
                            con.Close()

                        Next