[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] (IDEA) XML Persistent Datastore
I had some time to draw up my thoughts for an XML persistent datastore. This was included in an earlier document which I have included in the bottom. Requirements: - Persistence independent: - supports any database vendor (Oracle, Microsoft, Sybase, Hypersonic SQL, Ozone, etc). - done by container managed persistence - supports bean managed persistence. - This is done by abstracting the persistence methanism into another set of beans - I realized this was a requirement when working on massive size databases and when doing strange schema manipulation (like multi-site replication) - it should be possible (and this I am fuzzy on) to map every DOM object to a persistant object through EJB. Instead of using a DOM parser from OpenXML, XML4J you use the native one provided. - DOM queries based on XPath and XQL - can be used with massivly scalable databases or when you don't want to transfer a massive database. Currently DMOZ (http://www.dmoz.org) has 300M of RDF. An XPath query could allow us to transfer only 10M of it. - Security API: - public documents can't just be exposed to the whole world. I propose an Access Control List based security mechanism with inheritance (with the ability to override) - security meta information (user:mode) should be transfered through some sort of XML document over a secure channel. - This would allow the developer to query an XPath and if his query violated security no data was returned. IE /government/executive-branch/president/credit-information would not return anything thereby providing no information as to the potential existance of the data. - Data View - Conventional SQL supports the concepts of views. Views are defined as SQL queries on the original data - XML Views should be done with XPath/XQL - Schema constraints through XML schema - Performance search/index engine - currently modern HTTP search engines (Infoseek, Excite) treat HTML documents as one big CDATA section with all tagging removed. This needs to be fixed here. Since all data is basically XML it should be possible to import structured documents and run global (and fast) queries on them. This is possible because of XML Name spaces. Every DTD must be inserted here with a unique XML name space. - since the persistence mechanism is abstracted here the native database index can be use removing the burden of the developer from coding one. Just some ideas I have had... I am curious to see what everyone here thinks.... --------------------------- (overview) When the Internet started to experience massive growth one of the ways designed to conquer its massive amount of information was to setup a "search engine" which would spider the Internet or Intranet and calculate word counts from the HTML presentation layer. Later, databases started being written to the web application spectrum that added a gateway to the structured data. Later the W3C in its infinite wisdom published the XML specification to help split the difference and a standard give structure to documents that can easily be extended. (idea) Currently Java lacks an index server. One that parses a URL or filesystem and generates a META-Index (approx 40% original size) of the content and allows users to find a document within a filesystem or website based on a query. This lacks any structure as the user might search on something like China and either get the Country or the type of dishes. What I think is needed is a blend of the two. There is a *lot* of existing data that is HTML based (and will be for a while) that needs to be indexed within a 100% Java environment. Adding XML support to a Java Index Server would allow the user to enumerate a list of known DTDs and run a query on <country>China</country> (or XQL/XOQL/DOM) and obtain the doc (possibly HTMl after XSL re-format). (goals) I would just like to get feedback. There are some smart people here. ;) Kevin -- Kevin A Burton http://relativity.yi.org Mobile: 408-910-6145 xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1 To unsubscribe, mailto:majordomo@i... the following message; unsubscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
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