The indexes are structured in such a way that they can be used by more than one library in principle within a CBS database, i.e. by more than one ILN (Internal Library Number). But the structure of the indexes is useful also in the case that there is only one ILN / library. But when in the course of time more ILNs / libraries are going to use a CBS, the indexes are prepared for that.
In this context, we don't speak about ORSs, for which the indexes can be structured in a different way in certain respects.
For searching by "content" search keys (so not by searching by PPN a.o.) and for the search results, next starting points are applicable:
- All records on the main level are found, independent from the owner of the record, so independent from the fact whether a library has taken a record in use by adding local and/or copy data.
- Local data are found only by the library which has entered these local data, i.e. the concerning library / ILN.
- Copy data are found only by the library which has entered these copy data, i.e. the concerning library / ILN.
By limitations in the index software, it is not possible to make indexes containing fields on main, local and copy level on the conditions that all records (i.e. of all libraries) on the main level are found and also only the local and copy data of the library / ILN that does the search.
Now (May 2021), the following is possible:
- Separate indexes for the main level in such a way that these records can be found by all libraries / ILNs.
- Separate indexes for the local and/or copy data which can be found only by the library that entered the data.
Only "general" thesauri are used within the generic CBS structure. I.e. thesauri that can be used by all libraries / ILNs within a CBS database and that are accessible by all libraries / ILNs. The authority records in these general thesauri can be linked by means of a PPN to bibliographic fields on the main level, but too and at the same time to fields on local and/or copy level.
For searching by "content" search keys (so not by searching by PPN a.o.) and for the search results, next starting points are applicable:
- All authority records that meet the search criteria, are found.
- Plus the related bibliographical records which contain an authority PPN link on the main level.
- Plus the related bibliographical records which contain this authority PPN link on the local and/or copy level of the searching library / ILN.
- So minus the related bibliographical records which contain this authority PPN link on the local and/or copy level of other than the searching library / ILN.
In other words, not all links are always visible for the searching library / ILN. This means that the command rel tt (i.e. rel(ated) title records) finds only the records that meet the abovementioned criteria.
Contrary to general thesauri, private thesauri are not part of the general CBS MARC 21 indexes.
But when these are implemented, the PPN links from the bibliographic records to the private authority records are allowed only to the local and/or copy fields. PPN links on the main level of a bibliographic record to a private thesaurus are not allowed.
For bibliographic records the following documents have been consulted:
For authority records the following documents have been consulted:
In case of word indexes, identical search keys can be used for searching WorldCat as well as a CBS MARC 21 database. In this case a colon will follow the mnemonic, like ‘pn:’ for ‘personal name’.
For the phrase version of word indexes, we will use the identical mnemonic, and complete it by using the character ‘p’ for ‘phrase’ instead of the colon.[1]
Additional word and phrase indexes for the CBS fields are also part of the CBS MARC 21 configuration.
CBS MARC 21 uses the search attributes, as used for WorldCat, for word indexes only, unless a search attribute is defined for a phrase index only; when using the phrase version of an index the number for the search attribute is increased by 10000.
E.g. search attribute 4 is related to the title index. In a CBS MARC 21 database the word index uses search attribute 4. But for the corresponding phrase version we use search attribute 10004.
To be as complete as possible, we will also use the Z39.50 search attributes. That is why from time to time, you will find two items for an index in the attribute column.
For the search attributes of the CBS MARC 21 indexes, the following ranges have been determined:
For word indexes for CBS MARC 21 fields that are based on equivalent WorldCat attributes.
Remark: For the CBS MARC 21 system, several search attributes are hard-coded. E.g. the range 90XX is reserved for special purposes.
For phrase versions of indexes for CBS MARC 21 fields, the search attribute of the word version is used increased by 10,000.
[1] November 2020: The software and configuration need to be adapted to make it possible to use the colon (:) to search word indexes and the equal sign (=) to search phrase indexes. When this is realized, the “p” will not be necessary anymore.