Hellenic Academic Libraries Union Catalog is a slave physical union catalog. HALUC member-libraries autonomously create their own bibliographic databases and OPACs using their preferable ILS and format, but they send their bibliographic records to HALUC regularly, every six months. These bibliographic records undergo a default configuration process, during which identical bibliographic records are being unified, before their incorporation in HALUC database.
 
Every member-library’s bibliographic records, before their incorporation into HALUC, undergo the following basic workflow:

1) Bibliographic records Export by member-libraries (usually every 6 months).
2) All MARC21 bibliographic records are converted to UNIMARC.
3) Bibliographic records character – set is converted to the character set used by HALUC.
4) Conversion to format ISO-2709.
5) Abstraction of bibliographic fields unnecessary for HALUC (e.g. 9XX, 001, 003, 005, 8XX, except 801).
6) Exclusion of any record containing faults or omissions in UNIMARC structure (records without holdings information, without 001 and 005 fields and without or with faulty 100 field).
7) Creation, via a special algorithm, of the unique key for every single record. The key is created by using data from UNIMARC fields concerned with the item’s title, subtitle, ISBN, main intellectual responsibility, publication, series, publication year.
8) Abstraction of bibliographic records which are double or appear as double in the same bibliographic database (they pop up with the same unique key).
9) Input of bibliographic records into HALUC. When a bibliographic record is inserted into HALUC database, it undergoes a process during which it is identified and incorporated as a totally new record, or it is identified as an already existed record. In the second case, holding information, alternative/new subject descriptors and classification numbers are added to this already existed record.
10) Discarded bibliographic records are sent back to the member-library they belong to, in order to be checked and corrected.
11) Creation of pertinent statistical reports for the total of the member-libraries, as well as for each member-library separately.