Hi all, I'll add yet another concern to have in consideration: any standard MapInfo Pro will thrash any 3rd party setup since supporting intelligent TAB multi-editing is not natively supported by Pro (with proper locks etc.).
To succeed one needs a stringent environment, in which every single client conforms to the multi-editing setup and abstains from using all the standard table opening and updating methods. Including all tools from various sources ! Unless one has few users and dilligent IT enforcers, the setup will break at some point. I think this comes under what Paul calls "Resilience". I know that Michel talks about MapX, and here its much simpler, but multi-editing is inherently more interesting to contemplate in a Pro environment. Don't know if v8 will come to provide the necessary mechanisms to implement record/table locking. Best regards/Med venlig hilsen Lars V. Nielsen GisPro, Denmark http://www.gispro.dk/ http://www.gispro.biz/ ----- Original Message ----- From: <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, February 09, 2004 1:03 PM Subject: RE: MI-L MapInfo files on server Michel - I have seen this done successfully - GDC in London have a nice implementation inside a browser based deployment - it uses a flag set on a database to allow or stall edits being applied to a central TAB file. (GDC note - sorry if this isn't right! I liked the software...) If you have a fairly small group of users this is certainly going to be a lower cost deployment than an RDBMS. Mind you they are cheaper than they were and presumably the development will cost somebody money (your boss - your department - you?!?). You may find a complex system costs more than biting the bullet and buying a database product. My concern with a TAB file based multi user EDITING system (read-only is fine and I've seen it work on a large scale) is that you'd have to address the following - 1. Performance of the system - lots of users may end up waiting too long if each commit takes a few seconds. Doesn't take many of them and the system is locked up for minutes 2. Performance of the TAB file - you'll need to pack it often to ensure that the spatial indices don't get knackered (technical term) 3. Resilience - not sure about this at all - the same issue as with lots of people attempting to edit the same Word document - what if someones edits corrupts the file? 4. Rollback - not really achievable (yes I know you CAN do it but lots of code) 5. Proliferation of temporary files supporting user edits which you'd have to throw away - I know this also happens with linked tables but you don't have to write a line of code This probably betrays my bias and probably the budgets of the projects I've worked on and I know its an argument that will always rumble on - Paul Crisp Syntegra Innovation Place Delta Bank Road Newcastle NE11 9DJ Tel 0191 461 4522 Fax 0191 460 1987 -----Original Message----- From: Michel Wurtz [mailto:[EMAIL PROTECTED] Sent: 09 February 2004 10:51 To: [EMAIL PROTECTED] Subject: Re: MI-L MapInfo files on server B. Thoen a �crit : > On Sun, 8 Feb 2004, S�ren Lindqvist wrote: > > >>I am planning to move my tab files to a catalogue on a server. There will be >>3 to 4 users working with the map and I wonder if there is a simple easy way >>to set this up. I want all the users to have ability to work with the map. >>Any step by step to do this? > > > There's no simple solution. MapInfo locks tab files as soon as someone > makes a change and others cannot make edits on them until the first user > commits > the changes. You'll need to build some MapBasic tool that manages > multi-user edits; probably something along the lines of copying records to > a local table, allow edits, and then post them back to the master table. > Good luck! We are currently developping a solution based on locks at object level and the use of temporary layers to modify objets : 1- open the tab file exclusively (no one can access it) 2- flag the objects you want to modify 3- close the tab file, so it becomes readable by everybody 4- reopen it "readonly" 5- copy the flagged objects in a temporary layer 6- made what you want with them 7- close tab file and open it for writing (no exclusive use) 8- update modified objects and clear flags 9- close tab file and erase temporary layer the tab file is only locked during the steps 2 and 8, which are very short (some tens of seconds in the worst case : you are not doing this on more than a hundred objects We developed this mainly as a library based on MapX, in order to put Maps in some multiuser applications. We are going to do it for MapInfo (with MapBasic + probably a C++ dll for the speed), but are asking ourselves if we should wait for MapInfo 8.0 and a consistent d�velopment sheme inside and outside MapInfo instead of dealing with MapX on one side and MapBasic on the other side... -- Michel Wurtz MAAPAR/DGA/SDSI/CERIT/DIG --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 10323 ******************************************************************** This email may contain information which is privileged or confidential. If you are not the intended recipient of this email, please notify the sender immediately and delete it without reading, copying, storing, forwarding or disclosing its contents to any other person Thank you Check us out at http://www.syntegra.com ******************************************************************** --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 10325
