Solved

Open a table without its index

Posted on 1998-08-12
2
139 Views
Last Modified: 2010-04-04
How can I open a dBase Table when its associate index is not present ?
Well, if I try to open a table when its index associate is not present then BDE raise an exception. An solution for this problem should be open the table at design time but I can't do it because I don't know the table's name. I know the table's names just after run some code.
Somebody help me ?
0
Comment
Question by:ara72
  • 2
2 Comments
 
LVL 8

Accepted Solution

by:
ZifNab earned 100 total points
ID: 1361994
Hi ara72,

use DbiRegisterCallback,

an inprise example :

BDE API Examples (DbiRegisterCallback)
Registers a callback function for the client application.
--------------------------------------------------------------------------------
 
Example 1: Create a callback that handles the condition of a missing .MDX file for a dBASE file or a missing .CDX file for a FoxPro file:
//Function called by DbiRegisterCallBack
function myfunc(ecbType : CBType; iClientData : LongInt;
   pCbInfo : pCBInputDesc): CBRType; stdcall;
const
   READONLY = 'Read Only';
   FAILOPEN = 'Fail Open';  //The default
   OPENANDDETACH = 'Open and Detach';
var
  counter : integer;
begin
  case ecbtype of
    cbINPUTREQ:  //It's a callback of cbINPUTREQ type
      if pcbInfo.eCbInputId = cbiMDXMIssing then
      begin
        {
        //Simple loop to list all modes, could be used to give used
        //to give a choice
        for counter:= 0 to pcbInfo.iCount-1 do
          showmessage(pcbInfo.acbEntry[counter].szKeyWord + #13 +
                   pcbInfo.acbEntry[counter].szHelp);
        }
        for counter:=0 to pcbInfo.iCount-1 do
          if pcbInfo.acbEntry[counter].szKeyword = OPENANDDETACH then
          begin
            pcbInfo.iSelection:=counter+1;
            pcbInfo.bSave := FALSE;
            break;
          end;
      end
      else  //if
        ShowMessage('Unexpected eCbInputId');
  else  //Case
    ShowMessage('Unexpected ecbType')
  end;
end;

//Register the callback and open the table
procedure TForm1.Button2Click(Sender: TObject);
var
  cbinfo : CBInputDesc;
begin
  session.open;
  Check(DbiRegisterCallBack(
   nil,                          //Cursor (Optional)
   cbINPUTREQ,                   //Type of Callback
   longint(0),                   //Pass-through client data
   sizeof(CBInputDesc),          //Callback buffer len
   @cbinfo,                      //Pointer to callback function
   @myfunc                       //Call back fn being registered
));
   Table1.Open;

   //Unregister the callback
   Check(DbiRegisterCallBack(nil, cbINPUTREQ, 0, sizeof(CBInputDesc), nil , nil));
end;

Regards, Zif.
0
 
LVL 8

Expert Comment

by:ZifNab
ID: 1361995
ara72,

 an older solution :

Q:  I have a DBF table that I can't open because it is expecting an MDX (production index) file.  I lost (deleted) that file.  What do I do now?

A:  Byte 28 in the DBF file header indicates whether an MDX file is needed.  (0 = no MDX needed; 1 = MDX needed.)  Here is some code that makes the change for you.  It uses a radio group where the first item is NO MDX (element 0), and the second item is USES MDX (element 1).  This app also uses the TOpenDialog component.

procedure TForm1.Button1Click(Sender: TObject);
var
  f: file of byte;
  b: byte;
begin
  if OpenDialog1.execute then
  begin
    assignFile(f, OpenDialog1.FileName);
    reset(f);
    seek(f, 28);

    b := RadioGroup1.ItemIndex; {0 = no MDX; 1 = use MDX}
    write(f, b);
    closefile(f);
  end;
  OpenDialog1.FileName := '*.dbf'; {reset the filter}
end;

{ This code came from Lloyd's help file! }

Regards, zif.
0

Featured Post

Announcing the Most Valuable Experts of 2016

MVEs are more concerned with the satisfaction of those they help than with the considerable points they can earn. They are the types of people you feel privileged to call colleagues. Join us in honoring this amazing group of Experts.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Delphi : could not find program, '...exe' 2 164
Correct Component for Shopping Cart. 2 105
Delphi inherited method 6 67
Delphi: sending SMS on android platform 1 18
Have you ever had your Delphi form/application just hanging while waiting for data to load? This is the article to read if you want to learn some things about adding threads for data loading in the background. First, I'll setup a general applica…
In my programming career I have only very rarely run into situations where operator overloading would be of any use in my work.  Normally those situations involved math with either overly large numbers (hundreds of thousands of digits or accuracy re…
This Micro Tutorial will teach you how to censor certain areas of your screen. The example in this video will show a little boy's face being blurred. This will be demonstrated using Adobe Premiere Pro CS6.
This Micro Tutorial will give you a basic overview how to record your screen with Microsoft Expression Encoder. This program is still free and open for the public to download. This will be demonstrated using Microsoft Expression Encoder 4.

805 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question