Concurrency and XML?

[Guest_imported]

hi everyone,
We are in the process of designing a systemwhere the master data captured by the system should be available in XML. These files will be residing on a central location, accessed by various clients. We would also require that changes to the data should handle issues of concurrency, ie one user should not be allowed to change a master record when it is being changed by someone else. This is fairly simple to do had the data been residing in a database, but for reasons I dont want to get into, the client does not want a database in the picture. So is there any way that
a check for concurrency be implemented on XML files ?
Our team is new to XML and based on the little that we
know, this seems unlikely.
Would appreciate if anyone could help us out here.

Thanks!

 

[Miros]

1) You could have a secondary XML file which would simply be a list of recordnumbers and who's got them locked. This would be a pain to keep updated tho.

2) You could also have a datetimemodified value in your xml data and during the attempted save, if the datetimemodified on the server is newer than the datetime, the users would be warned/given an error that they are going to overwrite someone else's changes, depending on the degree of security you want.

If you want more info, I can dig out the DB Design book and see what's they have to say.

Rose