VB .Net: Error generating UpdateCommand with DBF

[MichMat]

Hi All,

Iam so green to VB that it just isnt funny.

I have read books and searchrd for 2 days now. The problem Im having is accesing a DBF file as database.

I tried using the "Add New Datasource" but I got nowhere. It seams that MS is looking for a file rather then a dirrectory which is where dbf files are recognised.

I have tried to code the connection my self and I have succeded in connecting and creating a dataset which I can then examine and change.

My problem is that I can save the changes back to the database. Im getting error

"Dynamic SQL generation for the UpdateCommand is not supported against a SelectCommand that does not return any key column information."

I dont know what to do. Key column isnt something that any of the tutorials mantioned and I obviously did not create the dbf file itself.

Here is my code

Imports System.Data
Imports Microsoft.Data.ODBC
 
Public Class Form1
 
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
 
        Dim vvvv As String
        Dim ds As New DataSet
        Dim da As OleDb.OleDbDataAdapter
        Dim sql As String
        Dim cb As OleDb.OleDbCommandBuilder
        Dim Conn As New System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=e:\pricePPJ;Extended Properties=dBase IV;")
 
        conn.Open()
 
        sql = "SELECT * FROM RSD.cdx "
        da = New OleDb.OleDbDataAdapter(sql, Conn)
        cb = New OleDb.OleDbCommandBuilder(da)
 
        da.Fill(ds, "AddressBook")
 
        vvvv = ds.Tables("AddressBook").Rows(0).Item(58)
        ds.Tables("AddressBook").Rows(0).Item(58) = "Change"
 
        Stop
 
        da.Update(ds, "AddressBook")
        conn.Close()
    End Sub
End Class

That is all I got.

Im not particularly attached to this method, so if there is a better way I'll be glad to learn it. I like the dataset because it lets me navigate through the content but if I can do this directly then that will be ok as well.

Thank you for any help

Michal

[Shashi Sadasivan]

A key column means that your table should have a primary key!
A primary key uniquiely identifies a row.

Hence, in the design view that cannot be created by visual studio, you willl have to write your own (manually)

edit:
Is the error/exception being created in the above code you mentioned?

[MichMat]

Yes,

The above code generates the error

Michal

[Shashi Sadasivan]

Can you edit the database file?

If you can, then create a primary index (identify which one could be a primary index)

[MichMat]

I dont know what the key is (I undestand the concempt).
The DBF file does have an index file cdx ???

Failing this what else can I do to change content of cells in a DBF. Surely with such an old technology this sort of thing cant be that difficult. Unless you are a novice like me.

I would seatle for just knowing how to change one cell value.

Michal