Synchronizing Screens on Network Database 
Author Message
 Synchronizing Screens on Network Database

Is there a method of synchronizing screens on two different users
stations viewing the same record when one makes a change? The changes
seem to show up the next time my program is opened, but not until
then.


Mon, 16 Mar 1998 03:00:00 GMT  
 Synchronizing Screens on Network Database


Quote:
> procedure Refresh;

> Description

> The Refresh method rereads all records from the dataset. Use Refresh
> to be certain that data controls display the latest information from
> the dataset. Calling Refresh may unexpectedly change the displayed
> data, potentially confusing the user.

> Now the only question that remains is how to know when to refresh the
> table. Surely there must be some way of checking the .lck file to see
> if any other user is using the table in question!?
> Is there some undocumented BDE call that will return a .modified for a
> table, that takes other users on a network into account?

> ps: DataBase Desktop does this quite successfully, so it must be
> possible. Visually, it would seem that they have included a timer that
> refreshes every second or two, but this seems more like a kludge than
> a solution.

I too would like to know how it is possible to know if the underlying
tables (TTable ot TQuery) have been changed by either anotherobject or
another user.

It would seem that Paradox for Windows (and presumably the underlying engine)
is aware that a change has taken place but how do we get it through to
Delphi?

--

 "Programming is mirroring the world, inside a computer"   Larry O'Brien 1991



Mon, 16 Mar 1998 03:00:00 GMT  
 Synchronizing Screens on Network Database

Quote:
>procedure Refresh;
>Description
>The Refresh method rereads all records from the dataset. Use Refresh
>to be certain that data controls display the latest information from
>the dataset. Calling Refresh may unexpectedly change the displayed
>data, potentially confusing the user.
>---
>Now the only question that remains is how to know when to refresh the
>table. Surely there must be some way of checking the .lck file to see
>if any other user is using the table in question!?
>Is there some undocumented BDE call that will return a .modified for a
>table, that takes other users on a network into account?
>ps: DataBase Desktop does this quite successfully, so it must be
>possible. Visually, it would seem that they have included a timer that
>refreshes every second or two, but this seems more like a kludge than
>a solution.
>---
>Clayton Andrews, Cape Town, ZA

Unless I am mistaken, calling the REFRESH method also POSTS any
changes on the viewed form. This would be unacceptable without any
confirmation.


Mon, 16 Mar 1998 03:00:00 GMT  
 Synchronizing Screens on Network Database

Quote:
>Is there a method of synchronizing screens on two different users
>stations viewing the same record when one makes a change? The changes
>seem to show up the next time my program is opened, but not until
>then.

---
procedure Refresh;

Description

The Refresh method rereads all records from the dataset. Use Refresh
to be certain that data controls display the latest information from
the dataset. Calling Refresh may unexpectedly change the displayed
data, potentially confusing the user.
---

Now the only question that remains is how to know when to refresh the
table. Surely there must be some way of checking the .lck file to see
if any other user is using the table in question!?
Is there some undocumented BDE call that will return a .modified for a
table, that takes other users on a network into account?

ps: DataBase Desktop does this quite successfully, so it must be
possible. Visually, it would seem that they have included a timer that
refreshes every second or two, but this seems more like a kludge than
a solution.

---
Clayton Andrews, Cape Town, ZA



Mon, 16 Mar 1998 03:00:00 GMT  
 Synchronizing Screens on Network Database

: Is there a method of synchronizing screens on two different users
: stations viewing the same record when one makes a change? The changes
: seem to show up the next time my program is opened, but not until
: then.

Are you using a TTable component?  If so, have you been using the
TTable.Refresh method to "synchronize" the screens?

--
        loveseekstears
stoEhr  hopedeniesfate
        sorrowcannotbe



Tue, 17 Mar 1998 03:00:00 GMT  
 Synchronizing Screens on Network Database


Quote:

>>Is there a method of synchronizing screens on two different users
>>stations viewing the same record when one makes a change? The changes
>>seem to show up the next time my program is opened, but not until
>>then.
>---
>procedure Refresh;

>Description

>The Refresh method rereads all records from the dataset. Use Refresh
>to be certain that data controls display the latest information from
>the dataset. Calling Refresh may unexpectedly change the displayed
>data, potentially confusing the user.
>---

>Now the only question that remains is how to know when to refresh the
>table. Surely there must be some way of checking the .lck file to see
>if any other user is using the table in question!?
>Is there some undocumented BDE call that will return a .modified for a
>table, that takes other users on a network into account?

>ps: DataBase Desktop does this quite successfully, so it must be
>possible. Visually, it would seem that they have included a timer that
>refreshes every second or two, but this seems more like a kludge than
>a solution.

There is an OnDataChange event associated with TDataSource, but I have been
unable to get it to work successfully to solve this problem.  

Ernest Ezis



Thu, 19 Mar 1998 03:00:00 GMT  
 
 [ 6 post ] 

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