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DBEngine.CompactDatabase and PermissionsI wonder if someone has a spare 5 minutes to test something for me. I posted to comp.databases.ms-access but have yet to receive any response. The question is: if I want to compact a secured mdb file from another mdb, do I need an Admins login? I think I have proved that you do not - but I may have overlooked something. So assuming you have a split, secured database handy with a read-only user, say Bob, who does not have permission to open the database exclusively: Login to the fe as Bob Make sure you have no bound forms open so the be is closed Press Ctrl-G for the immediate window and type: DBEngine.CompactDatabase PATH_1, PATH_2 where PATH_1 is the existing be path (e.g. C:\BackEnd.mdb) and PATH_2 is the path for the file to be created (e.g. C:\Compacted.mdb) Do you agree that Bob does not need permission to open the database exclusively, in order that he can run: DBEngine.CompactDatabase "C:\BackEnd.mdb", "C:\Compacted.mdb" Is there any documentation which explains this? You must have exclusive access to the MDB in order to compact it.
-- Show quoteHide quoteDoug Steele, Microsoft Access MVP http://I.Am/DougSteele (no private e-mails, please) "Anthony England" <aengl***@oops.co.uk> wrote in message news:5NSdnWE26r7RMbTZRVnysQ@bt.com... > Hello Newsgroup > I wonder if someone has a spare 5 minutes to test something for me. I > posted to comp.databases.ms-access but have yet to receive any response. > The question is: if I want to compact a secured mdb file from another mdb, > do I need an Admins login? I think I have proved that you do not - but I > may have overlooked something. > > So assuming you have a split, secured database handy with a read-only > user, say Bob, who does not have permission to open the database > exclusively: > Login to the fe as Bob > Make sure you have no bound forms open so the be is closed > Press Ctrl-G for the immediate window and type: > DBEngine.CompactDatabase PATH_1, PATH_2 > > where PATH_1 is the existing be path (e.g. C:\BackEnd.mdb) > and PATH_2 is the path for the file to be created (e.g. C:\Compacted.mdb) > > Do you agree that Bob does not need permission to open the database > exclusively, in order that he can run: > DBEngine.CompactDatabase "C:\BackEnd.mdb", "C:\Compacted.mdb" > > Is there any documentation which explains this? > Thank you for replying.
The backend database is closed and so is available for someone to open it exclusively. However, the user Bob does not have the permission to open it exclusively. And still, Bob can run the code DBEngine.CompactDatabase PATH_1, PATH_2 without any error. Do you have a spare minute to verify this for yourself with a secured split application where you can verify the user does not have the Open Exclusive permission, yet can still run the code? I am willing to accept that I may be mistaken, but I think I have proved otherwise. I know that your time is volunteered for free, but if you could check this on a real database, I would be grateful... Show quoteHide quote "Douglas J. Steele" <NOSPAM_djsteele@NOSPAM_canada.com> wrote in message news:%23V0XuirUGHA.2156@tk2msftngp13.phx.gbl... > You must have exclusive access to the MDB in order to compact it. > > -- > Doug Steele, Microsoft Access MVP > http://I.Am/DougSteele > (no private e-mails, please) > > > "Anthony England" <aengl***@oops.co.uk> wrote in message > news:5NSdnWE26r7RMbTZRVnysQ@bt.com... >> Hello Newsgroup >> I wonder if someone has a spare 5 minutes to test something for me. I >> posted to comp.databases.ms-access but have yet to receive any response. >> The question is: if I want to compact a secured mdb file from another >> mdb, do I need an Admins login? I think I have proved that you do not - >> but I may have overlooked something. >> >> So assuming you have a split, secured database handy with a read-only >> user, say Bob, who does not have permission to open the database >> exclusively: >> Login to the fe as Bob >> Make sure you have no bound forms open so the be is closed >> Press Ctrl-G for the immediate window and type: >> DBEngine.CompactDatabase PATH_1, PATH_2 >> >> where PATH_1 is the existing be path (e.g. C:\BackEnd.mdb) >> and PATH_2 is the path for the file to be created (e.g. C:\Compacted.mdb) >> >> Do you agree that Bob does not need permission to open the database >> exclusively, in order that he can run: >> DBEngine.CompactDatabase "C:\BackEnd.mdb", "C:\Compacted.mdb" >> >> Is there any documentation which explains this? >> > > Actually, I'm afraid I can't, as I don't have a database that meets the
criteria. -- Show quoteHide quoteDoug Steele, Microsoft Access MVP http://I.Am/DougSteele (no private e-mails, please) "Anthony England" <aengl***@oops.co.uk> wrote in message news:FqudnWQQP-jcI7TZnZ2dnUVZ8qGdnZ2d@bt.com... > Thank you for replying. > The backend database is closed and so is available for someone to open it > exclusively. > However, the user Bob does not have the permission to open it exclusively. > And still, Bob can run the code DBEngine.CompactDatabase PATH_1, PATH_2 > without any error. > > Do you have a spare minute to verify this for yourself with a secured > split application where you can verify the user does not have the Open > Exclusive permission, yet can still run the code? > > I am willing to accept that I may be mistaken, but I think I have proved > otherwise. I know that your time is volunteered for free, but if you > could check this on a real database, I would be grateful... > > > > "Douglas J. Steele" <NOSPAM_djsteele@NOSPAM_canada.com> wrote in message > news:%23V0XuirUGHA.2156@tk2msftngp13.phx.gbl... >> You must have exclusive access to the MDB in order to compact it. >> >> -- >> Doug Steele, Microsoft Access MVP >> http://I.Am/DougSteele >> (no private e-mails, please) >> >> >> "Anthony England" <aengl***@oops.co.uk> wrote in message >> news:5NSdnWE26r7RMbTZRVnysQ@bt.com... >>> Hello Newsgroup >>> I wonder if someone has a spare 5 minutes to test something for me. I >>> posted to comp.databases.ms-access but have yet to receive any response. >>> The question is: if I want to compact a secured mdb file from another >>> mdb, do I need an Admins login? I think I have proved that you do not - >>> but I may have overlooked something. >>> >>> So assuming you have a split, secured database handy with a read-only >>> user, say Bob, who does not have permission to open the database >>> exclusively: >>> Login to the fe as Bob >>> Make sure you have no bound forms open so the be is closed >>> Press Ctrl-G for the immediate window and type: >>> DBEngine.CompactDatabase PATH_1, PATH_2 >>> >>> where PATH_1 is the existing be path (e.g. C:\BackEnd.mdb) >>> and PATH_2 is the path for the file to be created (e.g. >>> C:\Compacted.mdb) >>> >>> Do you agree that Bob does not need permission to open the database >>> exclusively, in order that he can run: >>> DBEngine.CompactDatabase "C:\BackEnd.mdb", "C:\Compacted.mdb" >>> >>> Is there any documentation which explains this? >>> >> >> > > Anthony England wrote:
> Thank you for replying. That code succeeds because, as you said no one is in the mdb at the time > The backend database is closed and so is available for someone to > open it exclusively. > However, the user Bob does not have the permission to open it > exclusively. And still, Bob can run the code DBEngine.CompactDatabase > PATH_1, PATH_2 without any error. that Bob runs it. -- Joan Wild Microsoft Access MVP I would say (as an educated guess) that you'd need to be a member of
the Admins group (of the workgroup file that was used to seure the database), or, have Adminster permission on the database - which could be granted to /any/ user AFAIK. But it would be easy to test. Just log on as users with various perms until it works, no? Remember also: you could have a hidden user who was a member of the admins group or had administer permission to the database. (Hidden in the sense that no-one knew that user's name, or password). Then do a CreateWorkspace to create a workspace "as" that user & do the compact from out of that workspace. By that means, /any/ user (even the least priviliged one) could run that code to compact the db - evn though that user did not, him or her self, have sufficient permissions to do that. Google the Access groups on CreateWorkspace if you are npot aware of that technique. HTH, TC (MVP Access) http://tc2.atspace.com
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"TC" <aatcbbtcc***@yahoo.com> wrote in message Hi TCnews:1143593861.448941.64320@t31g2000cwb.googlegroups.com... >I would say (as an educated guess) that you'd need to be a member of > the Admins group (of the workgroup file that was used to seure the > database), or, have Adminster permission on the database - which could > be granted to /any/ user AFAIK. > > But it would be easy to test. Just log on as users with various perms > until it works, no? > > Remember also: you could have a hidden user who was a member of the > admins group or had administer permission to the database. (Hidden in > the sense that no-one knew that user's name, or password). Then do a > CreateWorkspace to create a workspace "as" that user & do the compact > from out of that workspace. By that means, /any/ user (even the least > priviliged one) could run that code to compact the db - evn though that > user did not, him or her self, have sufficient permissions to do that. > > Google the Access groups on CreateWorkspace if you are npot aware of > that technique. > > HTH, > TC (MVP Access) > http://tc2.atspace.com Thanks for the comments. Yes it should be easy to test - and I have. My test shows that you do not need to be a member of the Admins group, nor do you need permission to exclusively open the back-end in order that this code will work. DBEngine.CompactDatabase BACK_END_1, BACK_END_2 My test shows that the back-end must be "available to be opened exclusively" - that is no-one should be using it when the code from the front-end is run. Also the user who runs this code must have permissions to open the database - but this seems to be the only permission he needs. Now you could say "Well, you've answered the question for yourself, haven't you?" but I have seen enough posts from reputable sources (eg Douglas J. Steele) who say that you need permission to open exclusively for this - so perhaps my test was flawed. I understand that we all have other things to do, but it really would not take long for someone else to test this: Create a new workgroup file and set this as your default Change the Admin password to 'admin' Create two files C:\fe.mdb and C:\be.mdb Create a group 'Read-Only Users' and add a user 'Bob' to it Log in as 'Admin' to C:\be.mdb and remove permission from the 'Read-Only Users' group to open exclusively Log in as 'Bob' to C:\fe.mdb and run DBEngine.CompactDatabase "C:\be.mdb", "C:\be2.mdb" This should work, but any attempt to do a compact and repair from the GUI will fail. These were my results with Access XP with (probably) latest jet sp, but would be very grateful if someone else could verify. You need Open Exclusive to compact a database in Access.
You need exclusive access to compact a database using Jet. You used to need Open Exclusive to compact a database using Jet, but Jet no longer opens the database to compact it (and hence does not do a very good job anymore). (david) Show quoteHide quote "Anthony England" <aengl***@oops.co.uk> wrote in message news:dYOdnRMgpL18tLfZRVnyiQ@bt.com... > "TC" <aatcbbtcc***@yahoo.com> wrote in message > news:1143593861.448941.64320@t31g2000cwb.googlegroups.com... >>I would say (as an educated guess) that you'd need to be a member of >> the Admins group (of the workgroup file that was used to seure the >> database), or, have Adminster permission on the database - which could >> be granted to /any/ user AFAIK. >> >> But it would be easy to test. Just log on as users with various perms >> until it works, no? >> >> Remember also: you could have a hidden user who was a member of the >> admins group or had administer permission to the database. (Hidden in >> the sense that no-one knew that user's name, or password). Then do a >> CreateWorkspace to create a workspace "as" that user & do the compact >> from out of that workspace. By that means, /any/ user (even the least >> priviliged one) could run that code to compact the db - evn though that >> user did not, him or her self, have sufficient permissions to do that. >> >> Google the Access groups on CreateWorkspace if you are npot aware of >> that technique. >> >> HTH, >> TC (MVP Access) >> http://tc2.atspace.com > > > > Hi TC > Thanks for the comments. > Yes it should be easy to test - and I have. My test shows that you do not > need to be a member of the Admins group, nor do you need permission to > exclusively open the back-end in order that this code will work. > DBEngine.CompactDatabase BACK_END_1, BACK_END_2 > My test shows that the back-end must be "available to be opened > exclusively" - that is no-one should be using it when the code from the > front-end is run. Also the user who runs this code must have permissions > to open the database - but this seems to be the only permission he needs. > > Now you could say "Well, you've answered the question for yourself, > haven't you?" but I have seen enough posts from reputable sources (eg > Douglas J. Steele) who say that you need permission to open exclusively > for this - so perhaps my test was flawed. > > I understand that we all have other things to do, but it really would not > take long for someone else to test this: > Create a new workgroup file and set this as your default > Change the Admin password to 'admin' > Create two files C:\fe.mdb and C:\be.mdb > Create a group 'Read-Only Users' and add a user 'Bob' to it > Log in as 'Admin' to C:\be.mdb and remove permission from the 'Read-Only > Users' group to open exclusively > Log in as 'Bob' to C:\fe.mdb and run DBEngine.CompactDatabase "C:\be.mdb", > "C:\be2.mdb" > This should work, but any attempt to do a compact and repair from the GUI > will fail. > > These were my results with Access XP with (probably) latest jet sp, but > would be very grateful if someone else could verify. > Thank you David
You state this clearly and authoritavely. It ties up exactly with my tests. It must be true! Show quoteHide quote "david epsom dot com dot au" <david@epsomdotcomdotau> wrote in message news:e6$Bu0vUGHA.5588@TK2MSFTNGP09.phx.gbl... > You need Open Exclusive to compact a database in Access. > > You need exclusive access to compact a database using Jet. > > You used to need Open Exclusive to compact a database > using Jet, but Jet no longer opens the database to compact > it (and hence does not do a very good job anymore). > > (david) > > > "Anthony England" <aengl***@oops.co.uk> wrote in message > news:dYOdnRMgpL18tLfZRVnyiQ@bt.com... >> "TC" <aatcbbtcc***@yahoo.com> wrote in message >> news:1143593861.448941.64320@t31g2000cwb.googlegroups.com... >>>I would say (as an educated guess) that you'd need to be a member of >>> the Admins group (of the workgroup file that was used to seure the >>> database), or, have Adminster permission on the database - which could >>> be granted to /any/ user AFAIK. >>> >>> But it would be easy to test. Just log on as users with various perms >>> until it works, no? >>> >>> Remember also: you could have a hidden user who was a member of the >>> admins group or had administer permission to the database. (Hidden in >>> the sense that no-one knew that user's name, or password). Then do a >>> CreateWorkspace to create a workspace "as" that user & do the compact >>> from out of that workspace. By that means, /any/ user (even the least >>> priviliged one) could run that code to compact the db - evn though that >>> user did not, him or her self, have sufficient permissions to do that. >>> >>> Google the Access groups on CreateWorkspace if you are npot aware of >>> that technique. >>> >>> HTH, >>> TC (MVP Access) >>> http://tc2.atspace.com >> >> >> >> Hi TC >> Thanks for the comments. >> Yes it should be easy to test - and I have. My test shows that you do >> not need to be a member of the Admins group, nor do you need permission >> to exclusively open the back-end in order that this code will work. >> DBEngine.CompactDatabase BACK_END_1, BACK_END_2 >> My test shows that the back-end must be "available to be opened >> exclusively" - that is no-one should be using it when the code from the >> front-end is run. Also the user who runs this code must have permissions >> to open the database - but this seems to be the only permission he needs. >> >> Now you could say "Well, you've answered the question for yourself, >> haven't you?" but I have seen enough posts from reputable sources (eg >> Douglas J. Steele) who say that you need permission to open exclusively >> for this - so perhaps my test was flawed. >> >> I understand that we all have other things to do, but it really would not >> take long for someone else to test this: >> Create a new workgroup file and set this as your default >> Change the Admin password to 'admin' >> Create two files C:\fe.mdb and C:\be.mdb >> Create a group 'Read-Only Users' and add a user 'Bob' to it >> Log in as 'Admin' to C:\be.mdb and remove permission from the 'Read-Only >> Users' group to open exclusively >> Log in as 'Bob' to C:\fe.mdb and run DBEngine.CompactDatabase >> "C:\be.mdb", "C:\be2.mdb" >> This should work, but any attempt to do a compact and repair from the GUI >> will fail. >> >> These were my results with Access XP with (probably) latest jet sp, but >> would be very grateful if someone else could verify. >> > > Anthony England wrote:
> My test shows that the back-end must be "available to be opened Without going back & checking all the posts, I would imagine that he> exclusively" - that is no-one should be using it when the code from the > front-end is run. Also the user who runs this code must have permissions to > open the database - but this seems to be the only permission he needs. > > Now you could say "Well, you've answered the question for yourself, haven't > you?" but I have seen enough posts from reputable sources (eg Douglas J. > Steele) who say that you need permission to open exclusively for this - so > perhaps my test was flawed. was probably just saying, "you can't compact the database if anyone else is using it". But naturally I can not speak on his behalf. Think of it logically. If you have been able to compact the database, from a user who /does not/ have permission to open it exclusively, then, it is clearly /not/ a necessary requirement that the user has open exclusive permission. No two ways about it! > I understand that we all have other things to do, but it really would not You can do all that yoursef. Trust your own testing!> take long for someone else to test this: > Create a new workgroup file and set this as your default (snip) It would be different if Douglas hopped in & said: "It's impossible, you couldn't have done that!" - then there would be an issue for everone else to test. But there is no such issue at present AFAICS. Cheers, TC (MVP Access) http://tc2.atspace.com Hi TC
I was just worried that I had overlooked something - such as removing the permission from the user while it still remained for a group he belonged to. It probably goes back to some deep-rooted childhood self-doubt (or at least that's what my therapist would tell me). Anyway, David Epsom's post backs up exactly what my tests had shown. Thanks for responding Show quoteHide quote "TC" <aatcbbtcc***@yahoo.com> wrote in message news:1143615127.674578.125500@t31g2000cwb.googlegroups.com... > > Anthony England wrote: > >> My test shows that the back-end must be "available to be opened >> exclusively" - that is no-one should be using it when the code from the >> front-end is run. Also the user who runs this code must have permissions >> to >> open the database - but this seems to be the only permission he needs. >> >> Now you could say "Well, you've answered the question for yourself, >> haven't >> you?" but I have seen enough posts from reputable sources (eg Douglas J. >> Steele) who say that you need permission to open exclusively for this - >> so >> perhaps my test was flawed. > > Without going back & checking all the posts, I would imagine that he > was probably just saying, "you can't compact the database if anyone > else is using it". But naturally I can not speak on his behalf. > > Think of it logically. If you have been able to compact the database, > from a user who /does not/ have permission to open it exclusively, > then, it is clearly /not/ a necessary requirement that the user has > open exclusive permission. No two ways about it! > > >> I understand that we all have other things to do, but it really would not >> take long for someone else to test this: >> Create a new workgroup file and set this as your default > (snip) > > You can do all that yoursef. Trust your own testing! > > It would be different if Douglas hopped in & said: "It's impossible, > you couldn't have done that!" - then there would be an issue for > everone else to test. But there is no such issue at present AFAICS. > > Cheers, > TC (MVP Access) > http://tc2.atspace.com > "TC" <aatcbbtcc***@yahoo.com> wrote in message Yes, that's exactly what I was saying.news:1143615127.674578.125500@t31g2000cwb.googlegroups.com... >> >> Now you could say "Well, you've answered the question for yourself, >> haven't >> you?" but I have seen enough posts from reputable sources (eg Douglas J. >> Steele) who say that you need permission to open exclusively for this - >> so >> perhaps my test was flawed. > > Without going back & checking all the posts, I would imagine that he > was probably just saying, "you can't compact the database if anyone > else is using it". But naturally I can not speak on his behalf. -- Doug Steele, Microsoft Access MVP http://I.Am/DougSteele (no private e-mails, please)
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"Douglas J. Steele" <NOSPAM_djsteele@NOSPAM_canada.com> wrote in message Fair enough, but it's not as if the question was unclear:news:%23w$UXL4UGHA.4976@TK2MSFTNGP11.phx.gbl... > "TC" <aatcbbtcc***@yahoo.com> wrote in message > news:1143615127.674578.125500@t31g2000cwb.googlegroups.com... >>> >>> Now you could say "Well, you've answered the question for yourself, >>> haven't >>> you?" but I have seen enough posts from reputable sources (eg Douglas J. >>> Steele) who say that you need permission to open exclusively for this - >>> so >>> perhaps my test was flawed. >> >> Without going back & checking all the posts, I would imagine that he >> was probably just saying, "you can't compact the database if anyone >> else is using it". But naturally I can not speak on his behalf. > > Yes, that's exactly what I was saying. > > -- > Doug Steele, Microsoft Access MVP > http://I.Am/DougSteele > (no private e-mails, please) <<Do you agree that Bob does not need permission to open the database exclusively, in order that he can run: DBEngine.CompactDatabase "C:\BackEnd.mdb", "C:\Compacted.mdb">> Knowing what I know now, I would have answered: " I agree. He does not need this permission." Nevertheless, I am grateful to anyone who responds. Anthony England wrote:
> There's a difference between whether he can and whether he should. If no > <<Do you agree that Bob does not need permission to open the database > exclusively, in order that he can run: > DBEngine.CompactDatabase "C:\BackEnd.mdb", "C:\Compacted.mdb">> > > Knowing what I know now, I would have answered: > " I agree. He does not need this permission." one is in the backend when the code is run, then it will work. However, you should get an exclusive lock to do the compact. What if someone opens the backend during the compact? -- Joan Wild Microsoft Access MVP
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"Joan Wild" <jwild@nospamtyenet.com> wrote in message Hi Joannews:%23PnjZAAVGHA.4956@TK2MSFTNGP09.phx.gbl... > Anthony England wrote: >> >> <<Do you agree that Bob does not need permission to open the database >> exclusively, in order that he can run: >> DBEngine.CompactDatabase "C:\BackEnd.mdb", "C:\Compacted.mdb">> >> >> Knowing what I know now, I would have answered: >> " I agree. He does not need this permission." > > There's a difference between whether he can and whether he should. If no > one is in the backend when the code is run, then it will work. > > However, you should get an exclusive lock to do the compact. What if > someone opens the backend during the compact? > > -- > Joan Wild > Microsoft Access MVP This is part of routine which will automatically backup the data. It will be carried out when the last user closes the front end if a backup has not already been taken. One of the first steps is to temporarily re-name the backend, then take a copy before I do further processing on the copy. If I can re-name the file, then I know it was not being used and I can proceed safely. I do not know if it is possible for someone else to open the file while <DBEngine.CompactDatabase Path1, Path2> is running - perhaps it is, as David Epson says that Jet no longer opens the file. Could someone open it without any error in the above code so I would not know that all went according to plan? I don't know. However, I need to balance the risk of granting each and every user with Open Exclusive permissions on the back end with the risk of someone opening the temporary file with an obscure name like ~temp01.mdb in the couple of seconds it exists (assuming it is possible). I don't really see the problem with granting users (or more appropriately
the group they are a member of) exclusive open permission? -- Show quoteHide quoteJoan Wild Microsoft Access MVP Anthony England wrote: > "Joan Wild" <jwild@nospamtyenet.com> wrote in message > news:%23PnjZAAVGHA.4956@TK2MSFTNGP09.phx.gbl... >> Anthony England wrote: >>> >>> <<Do you agree that Bob does not need permission to open the >>> database exclusively, in order that he can run: >>> DBEngine.CompactDatabase "C:\BackEnd.mdb", "C:\Compacted.mdb">> >>> >>> Knowing what I know now, I would have answered: >>> " I agree. He does not need this permission." >> >> There's a difference between whether he can and whether he should. If no >> one is in the backend when the code is run, then it will work. >> >> However, you should get an exclusive lock to do the compact. What if >> someone opens the backend during the compact? >> >> -- >> Joan Wild >> Microsoft Access MVP > > > Hi Joan > This is part of routine which will automatically backup the data. It > will be carried out when the last user closes the front end if a > backup has not already been taken. One of the first steps is to > temporarily re-name the backend, then take a copy before I do further > processing on the copy. If I can re-name the file, then I know it > was not being used and I can proceed safely. > > I do not know if it is possible for someone else to open the file > while <DBEngine.CompactDatabase Path1, Path2> is running - perhaps it > is, as David Epson says that Jet no longer opens the file. Could > someone open it without any error in the above code so I would not > know that all went according to plan? I don't know. > > However, I need to balance the risk of granting each and every user > with Open Exclusive permissions on the back end with the risk of > someone opening the temporary file with an obscure name like > ~temp01.mdb in the couple of seconds it exists (assuming it is > possible). No, it's not a big issue. But if standard users shouldn't need this
permission then there is always the risk that one of them will either deliberately or mistakenly open the back-end exclusively and lock others out. True, the risk is small but if it brings no benefit, then what's the point? When you use the security wizard you notice that some of the standard groups (such as the update and read-only groups) are not allowed to open exclusively. My only reason for posting was that it was not clear that you need this permission to compact from Access but not to run the CompactDatabase method. Anyway, after all this fuss, I'll probably find that someone will manage to open and save the back-end with MS Word which puts the current concern about OpenExclusive permissions into perspective. Show quoteHide quote "Joan Wild" <jwild@nospamtyenet.com> wrote in message news:eHn0d2BVGHA.5248@TK2MSFTNGP10.phx.gbl... >I don't really see the problem with granting users (or more appropriately >the group they are a member of) exclusive open permission? > > -- > Joan Wild > Microsoft Access MVP > > Anthony England wrote: >> "Joan Wild" <jwild@nospamtyenet.com> wrote in message >> news:%23PnjZAAVGHA.4956@TK2MSFTNGP09.phx.gbl... >>> Anthony England wrote: >>>> >>>> <<Do you agree that Bob does not need permission to open the >>>> database exclusively, in order that he can run: >>>> DBEngine.CompactDatabase "C:\BackEnd.mdb", "C:\Compacted.mdb">> >>>> >>>> Knowing what I know now, I would have answered: >>>> " I agree. He does not need this permission." >>> >>> There's a difference between whether he can and whether he should. If no >>> one is in the backend when the code is run, then it will work. >>> >>> However, you should get an exclusive lock to do the compact. What if >>> someone opens the backend during the compact? >>> >>> -- >>> Joan Wild >>> Microsoft Access MVP >> >> >> Hi Joan >> This is part of routine which will automatically backup the data. It >> will be carried out when the last user closes the front end if a >> backup has not already been taken. One of the first steps is to >> temporarily re-name the backend, then take a copy before I do further >> processing on the copy. If I can re-name the file, then I know it >> was not being used and I can proceed safely. >> >> I do not know if it is possible for someone else to open the file >> while <DBEngine.CompactDatabase Path1, Path2> is running - perhaps it >> is, as David Epson says that Jet no longer opens the file. Could >> someone open it without any error in the above code so I would not >> know that all went according to plan? I don't know. >> >> However, I need to balance the risk of granting each and every user >> with Open Exclusive permissions on the back end with the risk of >> someone opening the temporary file with an obscure name like >> ~temp01.mdb in the couple of seconds it exists (assuming it is >> possible). > > ?
Open "c:\bs8.mdb" For Input Access Read Shared As #1 dbe.CompactDatabase "c:\a.mdb", "c:\b.mdb", DAO.dbLangGeneral (fails) You still get and need an exclusive lock to do a compact. You can't compact if someone is sharing the database, and you can't share the database while someone is compacting. It's just that when you use this method the open exclusive permission is not checked, because the jet compact function doesn't open the access project. Correct me if I'm wrong, but I thought that Jet 2.0 or 2.5, required open exclusive permission, but this was discontinued because with some kinds of corruption you couldn't 'open' the database, so you couldn't correct the corruption? (david) Show quoteHide quote "Joan Wild" <jwild@nospamtyenet.com> wrote in message news:%23PnjZAAVGHA.4956@TK2MSFTNGP09.phx.gbl... > Anthony England wrote: >> >> <<Do you agree that Bob does not need permission to open the database >> exclusively, in order that he can run: >> DBEngine.CompactDatabase "C:\BackEnd.mdb", "C:\Compacted.mdb">> >> >> Knowing what I know now, I would have answered: >> " I agree. He does not need this permission." > > There's a difference between whether he can and whether he should. If no > one is in the backend when the code is run, then it will work. > > However, you should get an exclusive lock to do the compact. What if > someone opens the backend during the compact? > > -- > Joan Wild > Microsoft Access MVP > Actually, I may have that wrong. It's been my experience that users do need
exclusive permission in order to compact a database. -- Show quoteHide quoteJoan Wild Microsoft Access MVP david epsom dot com dot au wrote: > ? > > Open "c:\bs8.mdb" For Input Access Read Shared As #1 > dbe.CompactDatabase "c:\a.mdb", "c:\b.mdb", DAO.dbLangGeneral > (fails) > > You still get and need an exclusive lock to do a compact. > You can't compact if someone is sharing the database, and > you can't share the database while someone is compacting. > > It's just that when you use this method the open exclusive > permission is not checked, because the jet compact function > doesn't open the access project. > > Correct me if I'm wrong, but I thought that Jet 2.0 or 2.5, > required open exclusive permission, but this was discontinued > because with some kinds of corruption you couldn't 'open' the > database, so you couldn't correct the corruption? > > (david) > > > > "Joan Wild" <jwild@nospamtyenet.com> wrote in message > news:%23PnjZAAVGHA.4956@TK2MSFTNGP09.phx.gbl... >> Anthony England wrote: >>> >>> <<Do you agree that Bob does not need permission to open the >>> database exclusively, in order that he can run: >>> DBEngine.CompactDatabase "C:\BackEnd.mdb", "C:\Compacted.mdb">> >>> >>> Knowing what I know now, I would have answered: >>> " I agree. He does not need this permission." >> >> There's a difference between whether he can and whether he should. If no >> one is in the backend when the code is run, then it will work. >> >> However, you should get an exclusive lock to do the compact. What if >> someone opens the backend during the compact? >> >> -- >> Joan Wild >> Microsoft Access MVP There is no Access 2.0/2.5 dbEngine object, so in
Access 2, the only way to compact a database was through Access, requiring the Open Exclusive permission. This meant you couldn't repair a database unless you could open it. To get around this problem, the compact/repair utility was created. The dbEngine object was introduced with Access 95, which I never used. (david) Show quoteHide quote "david epsom dot com dot au" <david@epsomdotcomdotau> wrote in message news:%23tEtupFVGHA.224@TK2MSFTNGP10.phx.gbl... > ? > > Open "c:\bs8.mdb" For Input Access Read Shared As #1 > dbe.CompactDatabase "c:\a.mdb", "c:\b.mdb", DAO.dbLangGeneral > (fails) > > You still get and need an exclusive lock to do a compact. > You can't compact if someone is sharing the database, and > you can't share the database while someone is compacting. > > It's just that when you use this method the open exclusive > permission is not checked, because the jet compact function > doesn't open the access project. > > Correct me if I'm wrong, but I thought that Jet 2.0 or 2.5, > required open exclusive permission, but this was discontinued > because with some kinds of corruption you couldn't 'open' the > database, so you couldn't correct the corruption? > > (david) > > > > "Joan Wild" <jwild@nospamtyenet.com> wrote in message > news:%23PnjZAAVGHA.4956@TK2MSFTNGP09.phx.gbl... >> Anthony England wrote: >>> >>> <<Do you agree that Bob does not need permission to open the database >>> exclusively, in order that he can run: >>> DBEngine.CompactDatabase "C:\BackEnd.mdb", "C:\Compacted.mdb">> >>> >>> Knowing what I know now, I would have answered: >>> " I agree. He does not need this permission." >> >> There's a difference between whether he can and whether he should. If no >> one is in the backend when the code is run, then it will work. >> >> However, you should get an exclusive lock to do the compact. What if >> someone opens the backend during the compact? >> >> -- >> Joan Wild >> Microsoft Access MVP >> > > 
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