how to find out a lost communication between client & server

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5 total messages Started by Jerri Chiu Mon, 07 May 2001 21:15

#616

Author: Jerri Chiu
Date: Mon, 07 May 2001 21:15

11 lines
1196 bytes

Hi,

i have a database application which lets a user log in at the start, it then
connects to a oracle database.  user may use the forms to execute queries on
the database.  my question is how do i catch when the database and my
program has a disconnection?  is there an error code, or time out on a
TQuery object?

thank you much for any suggestions, ideas.

Jerri Chiu

Re: how to find out a lost communication between client & server

#617

Author: Mark Cashman
Date: Wed, 09 May 2001 01:24

32 lines
1758 bytes

Hi, Jerri!

SQL Server times out in that situation; I imagine your query would.
So...

    try
    {
        Query1->Open();
    }
    catch (EDatabaseError &DatabaseError)
    {
        if (TimeOutMessage(DatabaseError.Message))
        {
            ReconnectDatabase();
        };
    };

Obviously you have to figure out what message is a timeout message and
you have to test whether reconnecting to the database in that state is
safe.

I hope this helps.

--
------
Mark Cashman (TeamB - C++ Builder), creator of The Temporal Doorway at
http://www.temporaldoorway.com
- Original digital art, writing, music and more -
C++ Builder / JBuilder Tips and The C++ Builder Programmer's Webring
(Join us!)
http://www.temporaldoorway.com/programming/index.htm
------

Re: how to find out a lost communication between client & server

#621

Author: Jerri Chiu
Date: Fri, 11 May 2001 21:39

47 lines
2199 bytes

Hi Mark!

thanks much...! that really helped, i just need to find out what is the
time-out message.  I couldn't find it from the C++ builder help file.

does anybody has any idea?  has anybody used it before?

Thanks much again!
Jerri Chiu


"Mark Cashman" <mcashman@temporaldoorway.com> wrote in message
news:3AF89C5C.3570E6D0@temporaldoorway.com...
> Hi, Jerri!
>
> SQL Server times out in that situation; I imagine your query would.
> So...
>
>     try
>     {
>         Query1->Open();
>     }
>     catch (EDatabaseError &DatabaseError)
>     {
>         if (TimeOutMessage(DatabaseError.Message))
>         {
>             ReconnectDatabase();
>         };
>     };
>
> Obviously you have to figure out what message is a timeout message and
> you have to test whether reconnecting to the database in that state is
> safe.
>
> I hope this helps.
>
> --
> ------
> Mark Cashman (TeamB - C++ Builder), creator of The Temporal Doorway at
> http://www.temporaldoorway.com
> - Original digital art, writing, music and more -
> C++ Builder / JBuilder Tips and The C++ Builder Programmer's Webring
> (Join us!)
> http://www.temporaldoorway.com/programming/index.htm
> ------
>
>

Re: how to find out a lost communication between client & server

#622

Author: Mark Cashman
Date: Fri, 11 May 2001 23:22

15 lines
1698 bytes

Hi, Jerri!

Just use the logic shown and force a timeout somehow (overload the
server, take the server down...) Then set the exception to display the
message you get, and pick some part of it that probably won't change -
that's what you are looking for.

------
Mark Cashman (TeamB - C++ Builder), creator of The Temporal Doorway at
http://www.temporaldoorway.com
- Original digital art, writing, music and more -
C++ Builder / JBuilder Tips and The C++ Builder Programmer's Webring
(Join us!)
http://www.temporaldoorway.com/programming/index.htm
------

Re: how to find out a lost communication between client & server

#644

Author: nospam
Date: Mon, 28 May 2001 15:01

19 lines
1533 bytes

Jerri,
You can check the "Connected" property of your connection object.
John

Jerri Chiu wrote:

> Hi,
> 
> i have a database application which lets a user log in at the start, it then
> connects to a oracle database.  user may use the forms to execute queries on
> the database.  my question is how do i catch when the database and my
> program has a disconnection?  is there an error code, or time out on a
> TQuery object?
> 
> thank you much for any suggestions, ideas.
> 
> Jerri Chiu
> 
>

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