Why new version ?
Until recently Supernova Catalogue was stored as s filebased system.
The data on SNe were connected with the data on their host galaxies
in the main file of the catalogue: each string presented data on
SN and on its host galaxy.
At the beginning of 2006 we started transformation of the Catalogue to
the database structure. The main reasons are as follows:
- The number of SNe discovered continuously grows and eventually will
become unmanageable for manual maintaining of the SNe Catalogue as we
do in the past.
There are galaxies with multiple SNe outbursts. The information
on these host galaxies is presented in several lines, corresponding
to each SN. So when the information on one galaxy is updated, it
is necessary to replace it in several lines. After the division
of tasks of updating the information on SNe and on host galaxies
this can be done by different authors. It is
possible to insert data on newly discovered SNe quickly and
to update information on the galaxies more seldom, when new
data become available.
Only one author can make changes in the file at certain moment.
But with growing number of SN discoveries it is necessary to
provide several authors with the possibility to edit the data
simultaneously. This becomes possible with the new structure,
the jobs of several authors can be duly distributed and coordinated.
In the file the data is strictly formatted, and if the information
for some SN does not fit in the format, the structure of all file
should be changed. In the database it is possible to foresee
future changes, as the data of variable length are permissible.
The task of adding new data to the catalogue can be further
systematized and divided into simple parts. Besides dividing all
the data into two main tables with information on SNe: "sn" and
on the galaxies: "galaxies", the constant parts of inserted data
are presented in separate tables - so called reference databases:
"bands", "cats", "optmaglim", "properties", "qualification",
Different galaxy catalogues can be used as source of data on
SNe host galaxies, that is why the table "map" was created. It
contains the identifications of galaxies in these catalogues.