[Last Call] Learn about multicloud storage options and how to improve your company's cloud strategy. Register Now

x
?
Solved

Detecting record lock in Paradox Table

Posted on 1998-11-30
4
Medium Priority
?
204 Views
Last Modified: 2010-04-04
I am writing an multi-tier application using Delphi3 C/S version.  Is there any way I can detect from client A if a record has been locked due to editing by any other clients ?
0
Comment
Question by:ray3898
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
4 Comments
 
LVL 1

Expert Comment

by:Gerhard100198
ID: 1348702
How about this:

Write a function that accepts the TDataSet name as a parameter and will return a TRUE value if the record is locked.

Then try and place the dataset in edit mode within a try except error handler. You could analyse the error in more detail to trap specifically for a situation where the record is locked. This function will however tell you if it is possible the allow the edit or not.

Example:

function IsLocked(TheDataSet: TDataSet): Boolean;
begin
   Result := False;
   try
     TheDataSet.Edit;
     TheDataSet.Cancel;
   Except
      Result := True;
   end;
end;

0
 
LVL 27

Expert Comment

by:kretzschmar
ID: 1348703
hi ray3898,

a other method

procedure TForm1.Button1Click(Sender: TObject); {Or other EventMethod}
var IsLocked : Bool;
begin
 if dbiisrecordlocked(table1.handle,IsLocked) = DBIERR_NONE then
   if IsLocked then showmessage ('Record Locked');
end;

This requires the unit BDE in the uses clause of your unit.

meikl
0
 

Author Comment

by:ray3898
ID: 1348704
It seems to me that your method is reside on the client side rather than the application side (back-end).  Since both client A and client B would receive a copy of the actual data (table1.db) from the application server, so all locking are taken place on the local copy but not on the actual table (am I right ?)  Therefore, what I want is when client A want to edit a record, the program will check directly from the application server to determine the current status of the record. Is it possible to do it and how can I do it ?

Thank you
0
 
LVL 3

Accepted Solution

by:
Ronald Buster earned 150 total points
ID: 1348705
I used to have the same problem, use the following statement,
just a code snippet from one of my sources

try

  ... whatever you want to do

except

   on E: EDBEngineError do

       begin

           ... record is proberly locked

       end;

end;

regards,

Cono
0

Featured Post

Tech or Treat!

Submit an article about your scariest tech experience—and the solution—and you’ll be automatically entered to win one of 4 fantastic tech gadgets.

Question has a verified solution.

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

A lot of questions regard threads in Delphi.   One of the more specific questions is how to show progress of the thread.   Updating a progressbar from inside a thread is a mistake. A solution to this would be to send a synchronized message to the…
Introduction The parallel port is a very commonly known port, it was widely used to connect a printer to the PC, if you look at the back of your computer, for those who don't have newer computers, there will be a port with 25 pins and a small print…
Visualize your data even better in Access queries. Given a date and a value, this lesson shows how to compare that value with the previous value, calculate the difference, and display a circle if the value is the same, an up triangle if it increased…
Want to learn how to record your desktop screen without having to use an outside camera. Click on this video and learn how to use the cool google extension called "Screencastify"! Step 1: Open a new google tab Step 2: Go to the left hand upper corn…
Suggested Courses

650 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