The music included is published in sets and series organized according to various criteria:
The Index Database currently contains ca. 307,000 records, with over 20 fields of information: names (composers, poets, librettists, editors); titles and alternate titles; language of text and text incipit; performing forces (medium); identifying numbers (item numbers, opus/thematic catalogue numbers, key); formats (full score, piano vocal score, parts, etc.); language; presence of non-standard clefs; figured bass and how treated; duration of piece (ifgiven in item); genres; musical incipit (if needed for identification); citations for performing editions based on the main work; and RISM source numbers. Only fields relevant to the individual piece are present.
The Index Database is linked to the Bibliography Database (ca. 14,000 citations). This database is searchable by composer, title, and series name and number. Linking the Bibliography and Index records is a standard edition number. From the Bibliography record, this number allows users to view all index entries for a particular title. From an Index record, this number enables users to link to the Bibliography title for quick searching in library catalogues.
Advanced search allows for searching by instrumentation, catalog number and more.