Hi,

I don't think this is covered by the recent post.

This is my deployable code for setting the config and temp tables path in 1.9. I am sure it is familiar to many!

procedure TdmStraw.DataModuleCreate(Sender: TObject);
begin
 ExeLocation := ExtractFilePath(Application.ExeName);
 engStraw.Active:=True;
 sesStraw.Connected:=True;
 with qryConfiguration do
 begin
   SQL.Text:='SELECT * FROM Databases WHERE Name=' + Engine.QuotedSQLStr('Straw');
   Open;
   if (RecordCount = 0) then
   begin
      Close;
      SQL.Text:='CREATE DATABASE "Straw" PATH '+
                 Engine.QuotedSQLStr(ExtractFilePath(Application.ExeName)+'Data');
      ExecSQL;
   end
   else Close
 end
end;

procedure TdmStraw.engStrawBeforeStart(Sender: TObject);
begin
 with engStraw do
 begin
   ConfigPath := ExeLocation;
   TempTablesPath := GetTempTablesPath;
 end;
 with sesStraw do
 begin
   LoginUser := 'Administrator';
   LoginPassword := 'EDBDefault';
 end;
 dbStraw.Database := 'Straw'
end;

This creates a new config file in whichever directory the user deploys to . It seems to works about 95% of the time as long as
engStraw.ConfigPath and engStraw.TempTables path are left blank and the engine is not active at compile time. After an upgrade to 2.02 (Build
10) it throws an error 409 (config path empty). If you fill in the config path, it works OK on the development machine but won't deploy to another
machine (as it can't unsurprisingly find the development path). What settings do I need to modify to get it working again.

Thanks

Peter

Peter


>This creates a new config file in whichever directory the user deploys to . It seems to works about 95% of the time as long as
>engStraw.ConfigPath and engStraw.TempTables path are left blank and the engine is not active at compile time. After an upgrade to 2.02 (Build
>10) it throws an error 409 (config path empty). If you fill in the config path, it works OK on the development machine but won't deploy to another
>machine (as it can't unsurprisingly find the development path). What settings do I need to modify to get it working again.

I think I can understand it not working if the engine is active in the IDE, probably a matter of timing of events (eg it could be set to active before the events are hooked up), but it should be 100% not 95%. Others may disagree but unless you're going to be starting and stopping the engine in the app I'd put all of the start up code in TdmStraw.DataModuleCreate. Its not exactly masses of code and its a lot easier to follow if its all in one place and it will all flow smoothly in the right order.

If you want to keep it as a separate function make it a function call from TdmStraw.DataModuleCreate rather than an event.

Roy Lambert [Team Elevate]

Roy Lambert wrote:

Peter

I think I can understand it not working if the engine is active in the IDE, probably a matter of timing of events (eg it could be set to active before
the events are hooked up), but it should be 100% not 95%. Others may disagree but unless you're going to be starting and stopping the engine in
the app I'd put all of the start up code in TdmStraw.DataModuleCreate. Its not exactly masses of code and its a lot easier to follow if its all in one
place and it will all flow smoothly in the right order.

If you want to keep it as a separate function make it a function call from TdmStraw.DataModuleCreate rather than an event.

Roy Lambert [Team Elevate]

Roy,

Thanks for the quick response and good thinking. If I take the code that assigns the paths out of the Engine.BeforeStart and stick it at the top of
the DataModule.OnCreate it seems to do the trick. Maybe, the examples should be changed as this is where I pinched my original code from! I
guess there is also a potential issue here if, as you say, someone wants to restart the engine during runtime.

Cheers

Peter

PS I agree, it should be 100%

Peter


Ever since I started using Delphi (my first foray into Windows events) I've always felt that the non-deterministic manner in which events can fire is a significant problem. Maybe it is deterministic if you know what's going on under the hood, and if you ever meet the guy who knows I'd like an introduction. I'd also like a few quid for every time I'd had to chase an error down stepping though a few gazillion lines of code because events aren't firing in the order I expected.

Roy Lambert

Peter,

<< After an upgrade to 2.02 (Build 10) it throws an error 409 (config path
empty). If you fill in the config path, it works OK on the development
machine but won't deploy to another machine (as it can't unsurprisingly find
the development path). What settings do I need to modify to get it working
again. >>

What line of code throws the "config path is empty" error ?

Are you sure that you're not leaving the engine set to Active at design-time
?   The empty configuration path check is actually done when a local session
tries to connect, so the code that you show should work fine.  In fact, it's
basically the same code that we use with the CDCollector application.

--
Tim Young
Elevate Software
www.elevatesoft.com

What line of code throws the "config path is empty" error ?

Are you sure that you're not leaving the engine set to Active at design-time
?   The empty configuration path check is actually done when a local session
tries to connect, so the code that you show should work fine.  In fact, it's
basically the same code that we use with the CDCollector application.

Tim,

Interestingly (perhaps), it is the connection to the session that throws the error (sesStraw.Connected := true). The
preceding "engStraw.Active:=True" doesn't cause a problem. If I set a breakpoint in the Engine.BeforeStart, this does not fire.

Yes (1000 times) the engine is not active - I discovered this one in my early attempts to deploy (at about version 1.05 I think). One thing that
may or may not be significant is that these tables were created in 1.09. I wasn't sure if they would be compatible with 2.02 but they do appear to
be apart from this (soluble) problem.

Peter

Peter


What I did to make sure of not having things set to active was to install GExperts and use it to set several properties to false - basically any of the TEDB... stuff.

Roy Lambert

>> Roy Lambert wrote:
>>
>> What I did to make sure of not having things set to active was to install GExperts and use it to set several properties to false -
>> basically any of the TEDB... stuff.

I have also used "engStraw.Close" as the first line of the data module's on create but the results haven't always been entirely predictable ...

Peter,

<< Interestingly (perhaps), it is the connection to the session that throws
the error (sesStraw.Connected := true). The
preceding "engStraw.Active:=True" doesn't cause a problem. If I set a
breakpoint in the Engine.BeforeStart, this does not fire. >>

So, you're saying that the BeforeStart event handler is not firing for the
TEDBEngine component when the Engine's Active property is set to True ?

--
Tim Young
Elevate Software
www.elevatesoft.com

"Tim Young [Elevate Software]" wrote:

<< So, you're saying that the BeforeStart event handler is not firing for the
TEDBEngine component when the Engine's Active property is set to True ? >>

Well, that would appear to be the case. With my code in the OP, if I set breakpoints at "ExeLocation := ExtractFilePath(Application.ExeName);
" in the OnCreate and "ConfigPath := ExeLocation;" in the BeforeStart, the latter does not fire before I get the 409 when I
execute "sesStraw.Connected:=True;" in the OnCreate event. I would not have expected this I guess but then maybe Roy has a point when he
talks about the order of events firing in Delphi not always being totally predictable ... ?