xml-dev - Re: XML database

[tpassin@home.com]

Huaxin Zhang asked about storing XML in a database.

> Perhaps this is an old question, but I still can't find answer anywhere:
>
> Suppose I have a hierarchy DOM structure, each node may have undefinite
> number of child nodes. How to save this may-be extremely large tree
> structured XML files into some kind of database rather than a large chunk
> in memory or flat file has been a problem for me for a long time.
>
> Would anybody help with me with this? I would prefer Relational DB, but
> seems I have to shift to OO-DB, which I know absolutely nothing about.
>
You will probably see several different kinds of responses because you have
not given us enough information.

- Do you need to store xml data that conforms to only one dtd, or many?
- Does the data you want to store look like a series of rows having the same
structure?
- Will there be ID/IDREF cross links?
- In another post, you mention querying the data.  Do you want to perform
any kind of query, just certain queries, or no queries?  Certain queries can
be done using xslt, some cannot or would be hard.
- How big will these documents be (roughly), and will there be a few or very
many?
- You mention DOM - are you thinking of storing the DOM structure, or an xml
document that you could get by serializing the DOM to an xml file?

There isn't any general answer as to how to store an xml document in a
database.  It can always be stored some way in an relational database, but
it may be cumbersome or give poor performance depending on the design of the
xml.  A lot depends too on the intended use.

Tom Passin