yes, you do need a sepetate TSession per thread - each database usually shares a single one, hence the problem.
N ----- Original Message ----- From: "Donovan J. Edye" <[EMAIL PROTECTED]> To: "Multiple recipients of list delphi" <[EMAIL PROTECTED]> Sent: Monday, October 08, 2001 3:54 PM Subject: Re: [DUG]: [Q] MIDAS (Socket Connection), BDE, Threads > R, > > Sorry. Part II. Is a TSession still necessary even though the thread and > the application have their own TDatabase components and inherently their > own Session? > > At 15:50 08/10/2001 +1300, you wrote: > >I have no idea about how MIDAS works but you definately need to use a > >seperate session with each thread when working with DBase etc. As to BDE > >crashes, me too! Any app that crashes the BDE will crash any other app > >using the BDE in my experiance. > > > >Robert Martin > >Software Engineer > >Wild Software Ltd > >>----- Original Message ----- > >>From: <mailto:[EMAIL PROTECTED]>Donovan J. Edye > >>To: <mailto:[EMAIL PROTECTED]>Multiple recipients of list delphi > >>Sent: Monday, October 08, 2001 2:49 PM > >>Subject: [DUG]: [Q] MIDAS (Socket Connection), BDE, Threads > >> > >>G'Day All, > >> > >>I have the following: > >> > >>- A component TCricketLiveScoringClient that uses a MIDAS socket > >>connection to make and handle a connection to a MIDAS server > >>- The above component uses a TTXProcessThread to monitor changes in a > >>local BDE table > >>- When a change is detected by the it uses > >>TCricketLiveScoringClient.ProcessTX() to send the transaction to the > >>MIDAS server > >> > >>However what I am finding is that if an exception is raised and the > >>thread terminated and the connection to the MIDAS server closed that the > >>application dies horribly with access violation(s), runtime error 216 > >>etc. So my questions are these: > >> > >>- The thread uses its own TDatabase connection (and not the TDatabase > >>connection of the application that contains the component). But does it > >>require a TSession component as well? Are there issues here to do with > >>the BDE/Threading? > >>- It appears to me that the AppServer property of the TSocketConnection > >>"disappears" out from under me. However no amount of: > >> > >> if not ((VarIsNull(FSocketConnection.AppServer)) AND (varEmpty = > >> VarType(FSocketConnection.AppServer)) AND > >> (varNull = VarType(FSocketConnection.AppServer))) then > >>seems to protect me from getting the access violation. > >> > >>Can anybody provide me with some pointers etc.? Below find the necessary > >>code, but if you need anything else then please ask. I am at a loss as to > >>how to solve this. Environment is D5.01 Enterprise. > >> > >>TIA > >> > >> > >>type > >> TNewTXDataEvent = procedure(ATXID : integer; ATXPayload : string; > >> TotalTXs : integer; > >> var EventCompleted : boolean; var EventCompletedSuccessfully : > >> boolean) of object; > >> > >> TTXProcessThread = class(TThread) > >> private > >> FDatabase : TDataBase; > >> FEventCompleted : boolean; > >> FEventCompletedSuccessfully : boolean; > >> FLastTxIDProcessed : integer; > >> //FSession : TSession; > >> FTXTable : TTable; > >> FNewTXDataEvent : TNewTXDataEvent; > >> protected > >> procedure Execute; override; > >> procedure FireCallBackEvent; > >> public > >> constructor Create(CreateSuspended : Boolean; ADBPath : string; > >> AStartTXID : integer; ANewTXData : TNewTXDataEvent); > >> destructor Destroy; override; > >> end; > >> > >>type > >> TCricketLiveScoringClient = class(TCustomPanel) > >> private > >> FActive : boolean; > >> FCricketAppGUID : string; > >> FGlobalMatchCode : string; > >> FLastTXProcessed : integer; > >> FSocketConnection : TSocketConnection; > >> FStatusPanel : TPanel; > >> FTXPanel : TPanel; > >> FMessages : TStringList; > >> FTXProcessingThread : TTXProcessThread; > >> FClientIP : string; > >> FDBPath : string; > >> FLoggedIn : boolean; > >> FMidasServerPort : SmallInt; > >> FMidasServerAddress : string; > >> procedure AddMessage(AMsg : string); > >> procedure CustomOnDblClick(Sender : TObject); > >> function Get_Local_IPAddr : string; > >> procedure HandleExceptionError(AProcName, AErr, ADelphiError : > >> string); > >> function Login : boolean; > >> function Logout : boolean; > >> procedure NewDataEvent(ATXID : integer; ATXPayload : string; > >> TotalTXs : integer; > >> var EventCompleted : boolean; var EventCompletedSuccessfully : > >> boolean); > >> function ProcessTX(AGlobalMatchCode : string; ATXID : Integer; > >> const ATXPayload : string; var ANextTXID : Integer; > >> var ASQLServerErrroCode : integer; var ASQLServerErrorDesc : > >> string) : WordBool; > >> procedure SetActive(const Value : boolean); > >> procedure SetGlobalMatchCode(const Value : string); > >> procedure SetMidasServerAddress(const Value : string); > >> procedure SetMidasServerPort(const Value : SmallInt); > >> protected > >> > >> public > >> constructor Create(AOwner : TComponent); override; > >> destructor Destroy; override; > >> published > >> property Active : boolean read FActive write SetActive; > >> property Align; > >> property BevelInner; > >> property BevelOuter; > >> property CricketAppGUID : string read FCricketAppGUID write > >> FCricketAppGUID; > >> property GlobalMatchCode : string read FGlobalMatchCode write > >> SetGlobalMatchCode; > >> property DBPath : string read FDBPath write FDBPath; > >> property MidasServerAddress : string read FMidasServerAddress > >> write SetMidasServerAddress; > >> property MidasServerPort : SmallInt read FMidasServerPort write > >> SetMidasServerPort; > >> end; > >> > >> > >>function TCricketLiveScoringClient.ProcessTX(AGlobalMatchCode : string; > >>ATXID : Integer; > >> const ATXPayload : string; var ANextTXID : Integer; > >> var ASQLServerErrroCode : integer; var ASQLServerErrorDesc : string) > >> : WordBool; > >>////////////////////////////////////////////////////////////////////////// ////// > >>// PURPOSE: Processes the supplied TX information > >>const > >> PROC_NAME = 'TCricketLiveScoringClient.ProcessTX'; > >> ERR_MSG = 'I was unable to process the transaction.'; > >>begin > >> //Show failure at this point > >> result := FALSE; > >> try > >> if not ((VarIsNull(FSocketConnection.AppServer)) AND (varEmpty = > >> VarType(FSocketConnection.AppServer)) AND > >> (varNull = VarType(FSocketConnection.AppServer))) then > >> begin > >> if FSocketConnection.AppServer.ProcessTX(FClientIP, > >> FCricketAppGUID, AGlobalMatchCode, ATXID, > >> ATXPayload, ANextTXID, ASQLServerErrroCode, > >> ASQLServerErrorDesc) = WordBool(TRUE) then > >> begin > >> result := TRUE; > >> FLastTXProcessed := ANextTXID - 1; > >> end; > >> end; > >> except > >> on E : Exception do > >> HandleExceptionError(PROC_NAME, ERR_MSG, E.Message); > >> end; > >>end; > >> > >> > >>-- Donovan > >>---------------------------------------------------------------------- > >>Donovan J. Edye [www.edye.wattle.id.au] > >>Namadgi Systems [www.namsys.com.au] > >>Voice: +61 2 6285-3460 > >>Fax: +61 2 6285-3459 > >>TVisualBasic = Class(None); > >>Heard just before the 'Big Bang': "...Uh Oh...." > >>---------------------------------------------------------------------- > >>GXExplorer [http://www.gxexplorer.org] Freeware Windows Explorer > >>replacement. Also includes freeware delphi windows explorer components. > >>---------------------------------------------------------------------- > > > >-- Donovan > >---------------------------------------------------------------------- > >Donovan J. Edye [www.edye.wattle.id.au] > >Namadgi Systems [www.namsys.com.au] > >Voice: +61 2 6285-3460 > >Fax: +61 2 6285-3459 > >TVisualBasic = Class(None); > >Heard just before the 'Big Bang': "...Uh Oh...." > >---------------------------------------------------------------------- > >GXExplorer [http://www.gxexplorer.org] Freeware Windows Explorer > >replacement. Also includes freeware delphi windows explorer components. > >---------------------------------------------------------------------- > --------------------------------------------------------------------------- New Zealand Delphi Users group - Delphi List - [EMAIL PROTECTED] Website: http://www.delphi.org.nz To UnSub, send email to: [EMAIL PROTECTED] with body of "unsubscribe delphi" Web Archive at: http://www.mail-archive.com/delphi%40delphi.org.nz/
