Barry


>OK who mentioned putting tables in the datamodule
>
>You can still put the TEDBTable, TEDBQuery and TDatasource on each form. But the thread still needs its own instantiated datamodule that contains the TEDBDatabase, TEDBEngine, TEDBSession.

Wrong! There is no requirement for a datamodule. I have a number of threads and not one of them uses a datamodule eg

type
TAlarmChecker = class(TThread)
private
 iSignal: TSimpleEvent;
 iUserID: string;
 iReportBack: HWND;
 iMsgNo: integer;
 iCrashMsg: integer;
 iNewEMailsMsg: integer;
 iEMailSkipMsg: integer;
 iSession: TEDBSession;
 iDatabase: TEDBDatabase;
 iUnreadEmails: TEDBQuery;
 iNewEmails: TEDBQuery;
 iLastEMail: integer;
 iIsAlarmWanted: TEDBQuery;
 iLTCAlarm: TEDBQuery;
 iCurrentCheck: integer;
 iSkippedEMails: TEDBQuery;
 iLastSkipped: integer;
 FBlinkEMail: boolean;
 FBlinkAlarms: boolean;
 FBlinkLTC: boolean;

constructor TAlarmChecker.Create(const AlarmsParams: TAlarmParams);
begin
inherited Create(True);
iLastSkipped := 0;
FBlinkEMail := False;
FBlinkAlarms := False;
FBlinkLTC := False;
iReportBack := AlarmsParams.ReportBack;
iMsgNo := AlarmsParams.MsgNo;
iCurrentCheck := AlarmsParams.CurrentCheck;
iCrashMsg := AlarmsParams.CrashMsg;
iNewEMailsMsg := AlarmsParams.NewEMailsMsg;
iEMailSkipMsg := AlarmsParams.EMailSkipMsg;
iSignal := TSimpleEvent.Create;
iUserID := AlarmsParams.UserID;
iSession := TEDBSession.Create(nil);
iSession.AutoSessionName := False;
iSession.Name := 'alarm' + IntToStr(ThreadID);
iSession.SessionName := iSession.Name;
iSession.LoginUser := iUserID;
iSession.LoginPassword := AlarmsParams.Password;
iSession.LocalTempTablesPath := AlarmsParams.TempPath;
iSession.LocalEncryptionPassword := AlarmsParams.Encryption;
iSession.LocalConfigPath := AlarmsParams.ConfigPath;
iSession.Connected := True;
iDatabase := TEDBDatabase.Create(nil);
iDatabase.Database := AlarmsParams.Database;
iDatabase.Name := 'alarmDB' + IntToStr(ThreadID);
iDatabase.DatabaseName := iDatabase.Name;
iDatabase.SessionName := iSession.SessionName;
PrepSkippedCheck;
PrepAnyNewEMails;
PrepEMailAlarm;
PrepProjectAlarm;
PrepLTCAlarm;
try
 iDatabase.Execute('DELETE FROM LastCalls WHERE (_Date - CURRENT_DATE) DAY > 90');
except
end;
FreeOnTerminate := True;
Resume;
end;

Roy,

>Wrong! There is no requirement for a datamodule. I have a number of threads and not one of them uses a datamodule<

Yes, you can do it that way. I stand corrected.

It means initializing and instantiating all of the database, session, and engine components individually when each database related form is created. This will work fine for small applications with one form.

Since I have events defined for some of these components and error reporting, I just find it easier to maintain the code in one central location, namely the data module.

But both scenarios will work fine.

Barry
You say "tomato" and I say "tomAto".

Not necessarily - Delphi object inheritance is a very powerful feature
so I have a base thread class with all the components and creating a DB
thread is as simple as inheriting from our class. We also use
datamodules and those are useful as well. Nice to have a choice

One thing to add is that engine is a singleton so all instances of the
engine component refer to same app level engine. Hence I personally do
not use engine in datamodules at all to avoid any chance of accidentally
changing any settings that affect the app.

Raul

On 8/12/2013 5:06 PM, Barry wrote:
>
> It means initializing and instantiating all of the database, session, and engine components individually when each database related form is created. This will work fine for small applications with one form.