Composition of the Database The Different Database Levels Composition of the Database The size of the database has grown from 3.9 million bibliographic records in 1986 to over 8.4 million today. The majority of these records are purchased from overseas, namely the LCMARC, UKMARC, OCLC Southeast Asian Microforms, PICA, BISA, MALMARC and PMSC. SILAS also obtains records from ABN & NZBN through a mutual exchange of SNB records. The major strength of the database lies also in the creation of original records input by the present members. ANB (Australian National Bibliography) lists books and pamphlets published in Australia. Overseas publications by Australians or with Australian subject content are also included. As of 17 September 1999 a total of 138,812 records covering the period Sep 88 - Sep 99 were loaded. Current records are added monthly. BISA (Bibliographic Information on Southeast Asia) is a cooperative project based at the University of Sydney. A total of 37,116 records were loaded into the SILAS database in January 1992. The main focus of BISA is on Indonesian materials, with a secondary focus on Malaysian and Singaporean materials. Filipino, Thai and Vietnamese materials have also been covered. LC (Library of Congress) tapes are loaded on a weekly basis. Although many individual records describe items catalogued in previous years, comprehensive coverage for books is from 1968 onwards, for serials from 1973, for films from 1972, and for music from 1984 onwards. Loading of LC tapes into the SILAS system began in September 1987. MALMARC records cover Malaysian and Indonesian imprints catalogued by the MALMARC Consortium in Malaysia. A total of 30,000 records was loaded on 18 January 1988. Some 3,178 records from the OCLC SEA Microfiche collection from 1978-1980 were converted to SILAS standards in March 1990. Some 43,171 NZBN (New Zealand Bibliographic Network) records were loaded into the SILAS database in January 1992. These are records about New Zealand or of New Zealand imprint. Current records are added quarterly. PICA records are from a consortium of academic libraries in the Netherlands. A total of 5,909 records of Southeast Asian imprints was loaded on 5 September 1987. A total of 150,000 PMSC (Professional Media Service Corp.) records of audio visual materials was loaded to the SILAS database by March 1997. Weekly updates of records were sent through FTP. Some 5,110 SNB records in English and Malay catalogued between April 1982 and July 1986 were converted from SINGMARC and loaded into the SILAS database in early 1987. Since then, all SNB titles have been inputted online. UK tapes are loaded on a weekly basis. Although many individual records describe items catalogued in previous years, comprehensive coverage is from 1980 onwards. Loading of UK tapes into the SILAS database began in November 1987. The WLN database of some 3.9 million records was loaded into SILAS by November 1986, forming the backbone of the SILAS database. Currently, SILAS subscribes to files from the Library of Congress, the British Library and the Professional Media Service Corporation (PMSC). Shortly, SILAS users will be able to enjoy direct access to OCLC’s WorldCat database, which contains over 44 million records from many different sources (now including WLN and PICA in the above list). SILAS is also looking to renew the exchange arrangement it had with ANB and NZNB through their new managing organisations. SILAS is constantly examining new potential sources of records in order to offer its members as much record copy as possible within a realistic budget. The Different Database Levels To obtain a good understanding of the workings of the SILAS system, you should firstly understand the database structure upon which the SILAS system has been built. At the highest level, the database contains a superset or "warehouse" of bibliographic records. The database contains every bibliographic record in the system irrespective of whether any SILAS member libraries have a copy of the title associated with the record. This database of nearly 8.5 million records forms the basis of SILAS copy cataloguing resources. This SILAS database is continuously refreshed through original cataloguing records contributed by SILAS members and the loading of records from other cataloguing utilities. Any updates to records are automatically flowed down to all member databases unless updates are protected from local specified IDD tags. The middle level of the SILAS database structure contains the National Union Catalogue. The NUC is automatically built and updated as libraries attach or delete their holdings on the system. The NUC shows users which libraries hold at least one copy of individual titles within the SILAS consortium. Finally, the institutional level contains all titles held by each individual SILAS member or institution. When records are claimed by any institution, the participant’s database is updated. This causes the NUC-level databases to be updated automatically. If an original catalogue record is added to an institution’s database, the effect is a simultaneous and automatic update to the NUC and SILAS database level (the warehouse—superset level). Attached to each institution is a review or working file where bibliographic records can be temporarily housed for review by peers or supervisory cataloguers before they are saved to the member’s institutional-level database. SILAS has a review file where members can send their bibliographic records for SILAS staff validation. home | sitemap | contact us | SILASweb © Copyright 2000 SILAS.