Работа с БД - VB

 Dim conn As New OleDbConnection
        conn.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=D:\DB\DB.accdb; Persist Security Info=False;"
        conn.Open()
        Dim a1 As String
        a1 = TextBox4.Text
        Dim c As New OleDbCommand
        c.Connection = conn
        c.CommandText = "select from Base where Цена =" & a1
        Dim ds As New DataSet
        Dim da As New OleDbDataAdapter(c)
        da.Fill(ds, "Base")
        Grid2.DataSource = ds
        Grid2.DataMember = "Base"
        c.ExecuteNonQuery()