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c++databasearangodbaqlfuerte

How to specify the database in an ArangoDb AQL query?

If have multiple databases defined on a particular ArangoDB server, how do I specify the database I'd like an AQL query to run against?

Running the query through the REST endpoint that includes the db name (substituted into [DBNAME] below) ie:

/_db/[DBNAME]/_api/cursor

doesn't seem to work. The error message says 'unknown path /_db/[DBNAME]/_api/cursor'

Is this something I have to specify in the query itself?

Also: The query I'm trying to run is:

FOR col in COLLECTIONS() RETURN col.name

Fwiw, I haven't found a way to set the "current" database through the REST API. Also, I'm accessing the REST API from C++ using fuerte.

Solution

  • Tom Regner deserves primary credit here for prompting the enquiry that produced this answer. I am posting my findings here as an answer to help others who might run into this.

    I don't know if this is a fuerte bug, shortcoming or just an api caveat that wasn't clear to me... BUT...

    In order for the '/_db/[DBNAME/' prefix in an endpoint (eg full endpoint '/_db/[DBNAME/_api/cursor') to be registered and used in the header of a ::arangodb::fuerte::Request, it is NOT sufficient (as of arangodb 3.5.3 and the fuerte version available at the time of this answer) to simply call:

    std::unique_ptr<fuerte::Request> request;
const char *endpoint = "/_db/[DBNAME/_api/cursor";
request = fuerte::createRequest(fuerte::RestVerb::Post,endpoint);
// and adding any arguments to the request using a VPackBuilder...
// in this case the query (omitted)

    To have the database name included as part of such a request, you must additionally call the following:

    request->header.parseArangoPath(endpoint);

    Failure to do so seems to result in an error about an 'unknown path'.

    Note 1: Simply setting the database member variable, ie

    request->header.database = "[DBNAME]";

    does not work.

    Note 2: that operations without the leading '/_db/[DBNAME]/' prefix, seem to work fine using the 'current' database. (which at least for me, seems to be stuck at '_system' since as far as I can tell, there doesn't seem to be an endpoint to change this via the HTTP REST Api.)