Thread View: borland.public.cppbuilder.database.multi-tier
3 messages
3 total messages
Started by lakis
Tue, 22 Mar 2005 10:27
datasnap access violation
Author: lakis
Date: Tue, 22 Mar 2005 10:27
Date: Tue, 22 Mar 2005 10:27
13 lines
1789 bytes
1789 bytes
i have used datasnap remote data module to create a multi tier database application... i have placed in the remote data module an ado connection ,4 ado tables and 4 dataset providers..i have also (of course a form1)..i want to when i click the start/shutdown button on the Form1 to stop or start the datasnap server...when i try to stop the adoconnection (with connected->false,or cancel()) i get an access violation,same for the tables(adotable->active=false) the same for the dataset providers..it seems that i cant change anything in the remote data module by using a button on the form1...of course i have included the file header(<include...)...what am i doing wrong? the funny thing is that if i put an adoconnection in my form and use a button to start stop it ,it works perfectly!
Re: datasnap access violation
Author: Mark Guerrieri
Date: Thu, 31 Mar 2005 22:25
Date: Thu, 31 Mar 2005 22:25
27 lines
2283 bytes
2283 bytes
> i have used datasnap remote data module to create a multi tier database > application... > i have placed in the remote data module an ado connection ,4 ado tables and > 4 dataset providers..i > have also (of course a form1)..i want to when i click the start/shutdown > button on the Form1 to stop or start the datasnap server...when i try to > stop the adoconnection (with connected->false,or cancel()) i get an access > violation,same for the tables(adotable->active=false) the same for the > dataset providers..it seems that i cant change anything in the remote data > module by using a button on the form1...of course i have included the file > header(<include...)...what am i doing wrong? > the funny thing is that if i put an adoconnection in my form and use a > button to start stop it ,it works perfectly! > By design, the DataSnap server should be running on one machine (with no user interface) and the client that accesses it should be running on another machine. At the least, they would be running in seperate prcesses on the same machine. Either way, there is no way to directly access the properties/methods of the components on the RDM from the client app. Your access violations are most likely the result of accessingg NULL/undefined pointers, since the form in the client has no access to the components in the RDM. Mark
Re: datasnap access violation
Author: billaras1234
Date: Fri, 01 Apr 2005 10:34
Date: Fri, 01 Apr 2005 10:34
40 lines
2966 bytes
2966 bytes
if i have understood correctly you mean to create a separate function inside the remore data module to activate ore not the compnents inside it (like ado tables..) and to call this function from another form..i have done this and i still get a access violation in memory...i dont understand what is going on..once the rdm starts nothing cant change it? i believe that there must be a way or it might be a borland bug � "Mark Guerrieri" <mguerrieri@nospam_cmsgrp.com> ������ ��� ������ news:424c78d6$1@newsgroups.borland.com... > > i have used datasnap remote data module to create a multi tier database > > application... > > i have placed in the remote data module an ado connection ,4 ado tables > and > > 4 dataset providers..i > > have also (of course a form1)..i want to when i click the start/shutdown > > button on the Form1 to stop or start the datasnap server...when i try to > > stop the adoconnection (with connected->false,or cancel()) i get an access > > violation,same for the tables(adotable->active=false) the same for the > > dataset providers..it seems that i cant change anything in the remote > data > > module by using a button on the form1...of course i have included the file > > header(<include...)...what am i doing wrong? > > the funny thing is that if i put an adoconnection in my form and use a > > button to start stop it ,it works perfectly! > > > > By design, the DataSnap server should be running on one machine (with no > user interface) and the client that accesses it should be running on another > machine. At the least, they would be running in seperate prcesses on the > same machine. Either way, there is no way to directly access the > properties/methods of the components on the RDM from the client app. Your > access violations are most likely the result of accessingg NULL/undefined > pointers, since the form in the client has no access to the components in > the RDM. > > Mark > >
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