[xquery-talk] questions about security and dynamically constructedqueries

[Michael Kay]

> 1. Most of the XQuery implementations that I am familiar with
>    supports security at the database level. An user connects to the
>    repository using a loginname/password. Once authenticated, the user
>    can run queries against all the data in the repository.
>    Is there any implementation that associates security per
>    document (or collection)?

Tamino has facilities that enable you to do this. It's not as
sophisticated as the mechanisms in SQL, but it's usually adequate.
> 
> 2. One XQuery implementation (that I am familiar with) has implemented
>    vendor extensions that allow constructing and executing a query
>    dynamically. Do other implementations support a similar 
> functionality?

Tamino doesn't let you do this "out of the box", but you could implement
the functionality if you really need it.
> 
> 3. In my XQuery code, I want to discover if a particular library is
>    available. Only if it is available, I want to execute a 
> function in the
>    library. If the library does not exist, that I want to 
> proceed ahead
>    and do other things. Can I do achieve this functionality 
> using only 
> XQuery?

XQuery has no equivalent of XSLT's function-available(): all functions
are bound statically.

Michael Kay