Re: Is CVS A Practical Means to Manage XML Versions InA Produc
On 09/17/2011 03:02 PM, David Lee wrote: > What it *doesn't* do is 'intelligent' diffs and versioning. A classic > case is someone may simply load a xml file into and editor and save it, > without changing any 'xml stuff' but whitespace may change and cause the > file to be versioned and presumed 'different'. Does that matter ? It > depends on your needs. Yes, it all depends. I think the OP might not be interested in tree-aware or XML-aware diffs and integrated query mechanisms. That is also ACID properties which are usually guaranteed through transactions in database systems -- or CAP in NoSQL systems. But yeah, I'm more interested in the database/storage part and maybe a bit biased ;-) > For our needs it doesn't matter at all. We just needed document management > at a document level and as long as the files are not corrupted and we can > assign unique versions and label and pull them, it works great. Now if > you want to question say 'what XML element changed and by what' then a text > based version control won't answer that, but you can use other (non version > control) XML diff tools, pull the 2 versions and diff them. Also if you > want the system to not create a new version unless the document has > semantically changed it won't do that. Hm, you also have to remember that such diff tools really compute diffs and can't be used for change detection (for instance they may try to generate minimal edit scripts, but an optimal tree-to-tree correction algorithm is known to have a CPU runtime complexity of O(n^3) and it may still not be what a user really has changed, that is most of the tools use some kind of heuristics to speed up the diff-computation but may in certain cases fail horribly, for example data-oriented XML is almost always a problem). If you want to determine the changes a user really has done you must have unique node IDs, whereas XML documents usually don't have unique IDs. ID-based algorithms are usually also much quicker. Furthermore even XML diff tools aren't sufficient if the user wants to have an overview about the changes, but all of that may not be what the OP wants anyway ;-) But as a side note -- with time aware XPath or even XQuery-extensions a versioned XML-DBS can be used to analyse time-dependent data, which might be significant in many areas. What do others think? best regards, Johannes
[Date Prev] | [Thread Prev] | [Thread Next] | [Date Next] -- [Date Index] | [Thread Index]
PURCHASE STYLUS STUDIO ONLINE TODAY!
Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!
Download The World's Best XML IDE!
Accelerate XML development with our award-winning XML IDE - Download a free trial today!
Subscribe in XML format