>> I sometimes find myself, in code, wanting to create a database, or more
>> specifically test if a database exists and create it if does not. The
>> database module appears not have functions to create (or delete databases).
>> Is this a deliberate design decision?
>
> Indeed it is; but we are still looking for a good solution to fill
> this obvious gap. Even if databases are pretty light-weight entities
> in BaseX, the creation of a new database within an XQuery expression
> may trigger numerous side effects related to other database
> operations. The main reason for that is the functional nature of
> XQuery and the "pending update list" of XQuery Update: all updating
> commands will become effective after the query itself has been
> evaluated. However, commands like db:add() or db:delete() commands
> will (currently) only end up on the list if the addressed database
> already exists. Another example: db:create() could overwrite a
> database that already existed, and some commands would possibly refer
> to the old instance, while other updating commands would access the
> new one.
>
> One general solution to this challenge would be the XQuery Scripting
> Extension [1], which allows you to execute commands sequentially
> (i.e., in an imperative manner). XQSE is definitely on our list, but
> which will require considerable time to realize -- mainly because a
> straightforward implementation would sabotage many of the existing
> functional optimizations in the code (some of the functional and
> imperative optimizations are even diametrical).
>
> In summary, I cannot give a satifsying answer yet except for the
> advice to use the BaseX commands, REST or XQJ (via
> XQExpression.executeCommand()), but I'm very open to ideas and
> proposals how to tackle this challenge.
>
> Christian
>
> [1]
http://www.w3.org/TR/xquery-sx-10/