BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Is this correct? (TADOConnection)          BorlandTalk.com Forum Index -> Delphi Databases (ADO) View previous topic :: View next topic   Author Message Frederico Pissarra Guest Posted: Sat Oct 21, 2006 12:59 am    Post subject: Is this correct? (TADOConnection) Hello!!! Taking a look at ADODB unit in $(DELPHI)\Source\VCL (I'm using D7 here), you can see the following code: -------------%<------------cut here -------------%<------------------------ destructor TADOConnection.Destroy; begin Destroying; Close; ClearRefs; FreeAndNil(FCommands); if FConnEventsID > 0 then OleCheck(ConnectionPoint.UnAdvise(FConnEventsID)); FConnEventsID := 0; FConnectionObject := nil; inherited Destroy; end; -------------%<------------cut here -------------%<------------------------ Notice that FConnectionObject is not released (calling IUnknown.Release), but the reference simply will point to nil. Is this correct? []s Fred Back to top Guest Posted: Sat Oct 21, 2006 2:24 am    Post subject: Re: Is this correct? (TADOConnection) Not sure what you are asking, the code is from the unit ADODB. Are you wondering if your connection/object is free at this point? Frederico Pissarra wrote: Quote: Hello!!! Taking a look at ADODB unit in $(DELPHI)\Source\VCL (I'm using D7 here), you can see the following code: -------------%<------------cut here -------------%<------------------------ destructor TADOConnection.Destroy; begin Destroying; Close; ClearRefs; FreeAndNil(FCommands); if FConnEventsID > 0 then OleCheck(ConnectionPoint.UnAdvise(FConnEventsID)); FConnEventsID := 0; FConnectionObject := nil; inherited Destroy; end; -------------%<------------cut here -------------%<------------------------ Notice that FConnectionObject is not released (calling IUnknown.Release), but the reference simply will point to nil. Is this correct? []s Fred Back to top Bill Dekleris Guest Posted: Sat Oct 21, 2006 8:11 am    Post subject: Re: Is this correct? (TADOConnection) Frederico, if you take a look at FConnectionObject's declaration, you'l see that it is a "pointer" to an interface (ADOInt._Connection) that descends from IInterface, and as such it is reference counted. So, when you assign nil to this pointer, the underlying object is freed. So, yes, the command is correct. Bill Dekleris Quasar Software. -- ----------------------------------------------------------------------------------------- http://www.infosnap.eu Home page of InfoSnap - the powerful, all-purpose information and knowledge-base manager. ----------------------------------------------------------------------------------------- Frederico Pissarra wrote: Quote: Hello!!! Taking a look at ADODB unit in $(DELPHI)\Source\VCL (I'm using D7 here), you can see the following code: -------------%<------------cut here -------------%<------------------------ destructor TADOConnection.Destroy; ... FConnectionObject := nil; ... end; -------------%<------------cut here -------------%<------------------------ Notice that FConnectionObject is not released (calling IUnknown.Release), but the reference simply will point to nil. Is this correct? []s Fred Back to top Frederico Pissarra Guest Posted: Mon Oct 23, 2006 6:40 pm    Post subject: Re: Is this correct? (TADOConnection) <danielk1 (AT) wi (DOT) rr.com> escreveu na mensagem news:1161379473.609229.42860 (AT) e3g2000cwe (DOT) googlegroups.com... Quote: Not sure what you are asking, the code is from the unit ADODB. Are you wondering if your connection/object is free at this point? Precisely.... Notice that connection object is created in the constructor in CreateADOObject() function - wich calls CoCreateInstance with the proper CLSID. CoCreateInstance will call AddRef() IUnknown's member, but at the destructor FConnectionObject is simply set to nil without calling Release()! This means any connection object will remain in memory until the processes dies... or am I wrong? []s Fred Quote: Frederico Pissarra wrote: Hello!!! Taking a look at ADODB unit in $(DELPHI)\Source\VCL (I'm using D7 here), you can see the following code: -------------%<------------cut here -------------%<------------------------ destructor TADOConnection.Destroy; begin Destroying; Close; ClearRefs; FreeAndNil(FCommands); if FConnEventsID > 0 then OleCheck(ConnectionPoint.UnAdvise(FConnEventsID)); FConnEventsID := 0; FConnectionObject := nil; inherited Destroy; end; -------------%<------------cut here -------------%<------------------------ Notice that FConnectionObject is not released (calling IUnknown.Release), but the reference simply will point to nil. Is this correct? []s Fred Back to top Frederico Pissarra Guest Posted: Mon Oct 23, 2006 6:41 pm    Post subject: Re: Is this correct? 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