Direct Access to the Science Data Catalog#

The EIS Science Data Catalog is implemented using the UIT database management system. This is a relational database format based losely on the dBASE standard used by such programs as Foxpro and Microsoft Access. Although the two formats are closely related, they are not compatible. Specifically, routines designed for use with dBASE will not work with a UiT database.

It is important to remember that a UIT database, like its dBASE cousins, is not an SQL database. In particular, the UIT database managment system does not allow for multiple writers, does not allow for distributed databases or allow for remote access.

The UIT database was initially developed for use with the Ultraviolet Imaging Telescope and is now used in a variety of scientific applications. Routines to read and write into the database exist only in IDL (Image Description Language). Unfortunately there is no API or other access to a UIT database from other languages.

In order to streamline access to EIS Science Data Catalog, several IDL objects have been developed. Use of these objects and methods allow for consistent access multiple databases. Two objects in particular are of interest to the user. The first is DB_TOOLS object which allows access to any UIT database. The second is the EIS_DB object which superclasses the DB_TOOLS object and is used to access the EIS Science Data Catalog. The rest of this document will primarily discuss the EIS_DB object, however many features of the DB_TOOLS object will be noted as they are available through the EIS_DB object.

Routines to read and write into the database exist only in IDL (Image Description Language). Is it IDL （Interactive Data Language）?

--visitor, 19-May-2007