I need to make a long running task in the background. I’m using OmniThreadLibrary hopping this could help me.
I use dbexpress+mssql driver. I can connect ok when is in the main thread, but get:
Project Project1.exe raised exception class TDBXError with message
‘DBX Error: Driver could not be properly initialized. Client library
may be missing, not installed properly, of the wrong version, or the
driver may be missing from the system path.’.
The connections are created in each thread, not shared datamodule:
type
TdbManager = class(TObject)
private
{ private declarations }
FCon: TSQLConnection;
public
{ public declarations }
procedure Open(Driver:String; aparams:TStringList);overload;
procedure Close;
constructor Create;
destructor Destroy;override;
end;
constructor TdbManager.Create;
begin
inherited Create;
FCon := TSQLConnection.Create(nil);
end;
procedure TdbManager.Open(Driver: String; aparams: TStringList);
var
i: Integer;
key:string;
begin
FCon.DriverName := Driver;
for i := 0 to params.Count - 1 do
begin
key := params.Names[i];
FCon.Params.Values[key] := params.Values[key];
end;
LogMsg('Open DB '+ Driver + ': ' + FHost + '\' + FDatabase);
FCon.Open;
LogMsg('Done.');
end;
And the background task is executed:
procedure TBackupPlan.OnScheduleTrigger(Sender: TScheduledEvent);
begin
Parallel.Async(procedure
begin
ExecuteDataTask( Sender.Name );
end);
end;
procedure TBackupPlan.ExecuteDataTask(const Name: String);
var
db:TdbManager;
begin
db := nil;
db := TSqlServerManager.Create;
db.Open(self.Driver, options);
result := db;
end;
If I execute this directly, open ok. If I use Parallel.Async then get the error. What is happend here?
I found information about this here:
http://docwiki.embarcadero.com/RADStudio/en/DbExpress_Database_Specific_Information