Thanks Mapraputa,
Thanks for putting some time to reply. I really appreciated. Actually i was king of frustrated because I was trying to understand/learn something and I was sort of help. Anyway sorry...
I have some doubts ( in red) as per your answer.
How do we use XML with a very larger database
application?
First, we do not have to. Maybe we do not! XML isn't particularly good format in aspect of performance, and this can matter if a database is very large...
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#1 am I correct if I say XML is only for small application like web application?
#2 with database XML has performance issue?
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Are we supposed to create a XML file from the output of database query, like a text file (putting strings together)?
Most of latest versions of RDMS can upload or unload data in XML format. If not, than we can write the results of queries in a text file, like you said.
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I learned something here. Most of the DBMS provides function to unload/load data in XML format. But? ..
# 1 how do I specify in what XML structure DBMS is going to load data from database?
# 2 basically is there a way we can specify DTD or XML schema to DBMS in order to get output according to that DTD or Schema?
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Then use associated technologies on the XML file (DOM , SAX, XSLT, XPATH, XSLT ..) for the data representation or transportation?
For data transportation we do not need XML-related technologies, we would use network technologies (or burn CD and send it by usual mail ) For data representation, we can use XSLT, and the usage may vary from a simple single stylesheet, to the full-blown publishing framework. (There is a whole book about it: Cocoon 2 Programming: Web Publishing with XML and Java Or we could use DOM/SAX. But XML is not the only technology that can help with data representation, it's just recently most hyped technology.
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#1 By transportation I meant, how do we transfer data read from a XML file on server to the client application ( like webpage, or a
applet..)
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And use the same XML file for data manipulation using DOM or SAX (like add more elements or delete or modify the values of XML elements). Finally use the updated DOM? Or XML? File to update database. ( but how?)
I am not sure I understand your scenario. Why would we unload data in XML format, make data manipulations in this format and then load data back? Why not to make all manipulations in database itself? This is much easier. If we received some data as an XML file, and we need to upload them into a database, then again, most vendors already provided their databases with such function. If not, then we would probably read an input file in a DOM, and then use JDBC and SQL to update database. You might find more detailed answer (like this one ) if you search our JDBC forum.
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#1 I was thinking of something like that, you have list of employee retrieve from database in XML format, then create the DOM from that file then somehow( not sure how) display this list to user in client application, user can change some values for any of employee or may add a new employee. Internally we do this all manipulation in DOM then once use is done, update database from updated DOM with new/modified data.
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I hope you/someone else would provide some comments here.
thanks
[ December 27, 2002: Message edited by: Vivek Saxena ]
[ December 27, 2002: Message edited by: Vivek Saxena ]