Previous: The Captive Account and Mailserver
Up: The Captive Account and Mailserver
Previous Page: The Captive Account and Mailserver
Next Page: Access
An archive user has interactive access to the Observations Catalogue, but access to the data only by request. The actual observations are stored off-line and have to be retrieved by the archive operators. A de-archiving request is subject to authorization by the archive manager, in order to safeguard (possible) proprietary rights of the original owner(s) of the data.
The program ARCQUERY allows the user to query the Observations Catalogue and to select observations of interest in a `query table'. This software can be used interactively (on the captive account) or in batch mode (via the server). At the end of a query session, the user may make a request for the selected observations to be de-archived. Such a request, however, can only be processed if the user has provided address information: the archive (manager) requires knowledge of who, and where, the user is. In particular, a user identifies him or herself with up to 4 initials on login, and, preferably on first-time usage, may provide additional information with the `address' facility. The database system communicates with its users via electronic mail, and an E-mail address has therefore to be provided as part of the user identification. Successful processing of a request includes the mailing of a dearchiving log to the user, and, of course, sending the data off on a FITS tape.
All files created during a query session are identified by the initials of the user. At the end of a session the tables and listings created during that session (the `query context') may be saved for future use. At the beginning of each query session the program checks whether there are any saved results from a previous session with the given user identification (initials) and, if found, offers the option to restore them. The query context is updated after the execution of every command; recovery from accidental exit, a system crash, or a similar disaster, is therefore straightforward.
At any level of the query process HELP information is available on line; the simplest way of accessing HELP is by typing a question mark ` ?' at the point where the user gets lost. A more complete description of this facility is given in section .
A full description of ARCQUERY command, command qualifiers, keywords and keyword qualifiers is given in sections to of part II of this manual. The ARCQUERY command interpreter works with a minimal matching method: commands, qualifiers and keywords alike may be abbreviated to an unambiguous combination of the leading characters; upper case or lower case may be used.
An archive user can define a set of user-specific defaults and symbols, which can be modified at any time during the session either permanently or temporarily. It is possible to do this in an initialization file, which will be executed automatically when one starts ARCQUERY.