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", "sntypes", "surveys". 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.