Types of servers

The types of database which may be specified for keyword serv_type are as follows. If an unrecognised type is specified it will be ignored (to permit future extensions).

catalog

The database is a simple catalogue; this is the simplest and most common option.

archive

The database is an archive. This option is similar to `catalog', but the table returned may contain special columns whose values are URLs giving access to `bulk data' (images, spectra, time-series etc) for the selected objects. See Section  for details of these special columns.

namesvr

The database is a name server. The only type of query permitted is to submit to the server a character string corresponding to the name of an astronomical object. The server returns a TST catalogue with a single row and three columns. The row corresponds to the object named and the three columns are: identifier (name), Right Ascension and Declination. See configuration file simpleconfig.cfg for an example of a namesvr entry.

imagesvr

The database is an image server. See Section .

local

The database is a local catalogue in the TST format.

directory

The `database' is another configuration file. This facility allows a tree (or rather network, since recursion is permitted) of linked configuration files to be built up. The url keyword gives the URL of the destination configuration file. The term `directory' comes from making an analogy with an hierachical file system. See configuration file simpleconfig.cfg for an example.