I'm creating a EWB module and in a thread I'm trying to Create a EDBTable but as soon as I open it I get an access violation.

The AppSession and the AppDataBase is placed on Unit1.

Uses
edbcomps,
 DB;
implementation
uses
   unit1;

procedure SendThread.Execute;
var
MyTable: TEDBTable;

MyTable := TEDBTable.Create(nil);
With MyTable do
            begin
                    DatabaseName := 'AppData';
                    SessionName := 'Comca';
                    TableName := 'Customer';
                    Readonly := True;
                    IndexFieldNames := 'ID';
                    Open;
                    First;
                    While (not MyTable.Eof) do
                              begin
                                       // code here
                                      Next;
                              end;
                   Close;
                   Free;
            end;         

I tried to search the Forum but most tables are created using SQL.

Thanks,
Kim

I have no idea if I'm right but is it possible to create a table with a nil owner, or does it require a control?

I'd try changing:

MyTable := TEDBTable.Create(nil);

to

MyTable := TEDBTable.Create(Self);

and see if that resolves the issue.

(I'm probably wrong, but something to try while you're waiting for someone more knowledgeable than me to respond )

Cheers

Adam.

KimHJ


If this is being created in a thread then you may have trouble later on anyway since you're not maintaining full isolation. Have a read of this section in the pdf manual "4.3 Multi-Threaded Applications"

Where are the session & database created - are they created before you try and open the table?


Roy Lambert

Roy Lambert wrote:

> thread

Good point. Here is my code that I use from all my threads:

function PrepareSession(stMode : TSessionType) : TEDBSession;
begin
   Result := TEDBSession.Create(nil);
   Result.AutoSessionName := true;
   Result.LocalConfigPath := g_xStartupConfig.DatabasePath;
   case stMode of
   SESSION_ADMIN:
      begin
         Result.LoginUser := 'Administrator';
         Result.LoginPassword := 'EDBDefault';
      end;
   SESSION_STANDARD:
      begin
         Result.LoginUser := 'Something';
         Result.LoginPassword := 'another';
      end;
   else //    SESSION_READONLY:
      begin
         Result.LoginUser := 'ReadOnly';
         Result.LoginPassword := 'yeahright';
      end;
   end;
//   Result.LocalEncryptionPassword := GetPassword;
   Result.Open;
end;

procedure TProductQuery.PrepareDatabase;
begin
   if not assigned(m_xThreadSession) then
   begin
      m_xThreadSession := PrepareSession(SESSION_STANDARD);
   end;
end;


function TProductQuery.PrepareQuery: TEDBQuery;
begin
   PrepareDatabase;

   Result := TEDBQuery.Create(nil);
   Result.SessionName := m_xThreadSession.SessionName;
   Result.DatabaseName := g_xStartupConfig.DatabaseName;
end;


procedure TProductQuery.FixProducts;
var
   xWorkQuery : TEDBQuery;   // query used to find info
begin
   xWorkQuery := nil;
   try
      xWorkQuery := PrepareQuery;
....

--

Matthew Jones

Kim


In the binaries newsgroup
Message-ID: <52BA3A3F-C46E-4012-9985-09B894FAFF3B@news.elevatesoft.com>
Date: Sat, 30 Nov 2013 12:51:42 +0000
Subject: Roy Lambert's Tnlhxxx stuff

In Homebrew.zip you'll find a unit nlhEDB - this contains the code I use to do this sort of thing.

Roy Lambert

Matthew


Oh good we now have all your passwords - hacking here we come.

Roy Lambert

Roy Lambert wrote:

> passwords

Aaargh!

8-)

--

Matthew Jones

Kim,

<< I'm creating a EWB module and in a thread I'm trying to Create a EDBTable but as soon as I open it I get an access violation. >>

As pointed out, you need to keep the session, database, and dataset components (table, query, stored proc/func, script) isolated from other threads, per this information:

https://www.elevatesoft.com/manual?action=viewtopic&id=edb2&product=rsdelphiwin32&version=10T&topic=Multi_Threaded_Applications

Tim Young
Elevate Software
www.elevatesoft.com

Tim Young [Elevate Software] wrote:

>>As pointed out, you need to keep the session, database, and dataset components (table, query, stored proc/func, >>script) isolated from other threads, per this information:

Thanks to everyone.

I was just surprised that I need to create a session and database since you could have unlimited number (I don't know if there is a limited) of dataset's connected to the same Sessions and Database.

I can drop a Session and a Database and 50 Dataset on a form and have all 50 connect to the same table and all 50 using a different index.

Thanks
Kim

"Matthew Jones" wrote:

>>Good point. Here is my code that I use from all my threads:

function PrepareSession(stMode : TSessionType) : TEDBSession;
   begin
   Result := TEDBSession.Create(nil);
   Result.AutoSessionName := true;
   Result.LocalConfigPath := g_xStartupConfig.DatabasePath; <<

Matthew I'm a little confused about the AutoSessionName.
I thought the SessionName always have to be the name of the Session you had created in ElevateDB Manager.

I see you then add a LocalConfigPath is this instead of the SessionName?

Since I connect Remote and not Local would I still be able to use AutoSessionName?

I have twenty different databases in my session and when a request is sent to the module it change to the database associated with the login.

How will I be able to extract the localConfigPath for the session since I use a sessionname for connecting?
I check my Session when the it connect and the LocalSessionPath is blank.

Thanks,
Kim