1.2 Basic Components of a DYABOLA Database

Titles The titles are the most important components of a DYABOLA database. They are the smallest possible independent units of information. All other components are made up of several titles, describe relationships between such titles, or depend on a title. The title itself consists of three elements: a title text, a record number and the descriptors. The title text functions as a designation. It can just as easily be the name of a person, a date, or a longer grave inscription. It is possible to prepare different "types of title text", in order to distinguish between different axiomatically separate natural phenomena. As a general rule these are, for example, objects, persons, places, time concepts, events, sources, pictures and literature. The record number is necessary as a clear identification number, since different titles can of course have the same title text. Just think of common names like "Smith, J." or the paratactic "columns" of an early Christian basilica (whose position in the nave is a descriptor and does not belong in the title text). The record number does not necessarily appear for the user; however, if, for example, he or she noted down the record number after an earlier search, it can be used to get directly to an ambiguous title. The descriptors fill a title with meaning. There are two main types of descriptor: the reference and the dependent descriptor. Both have the function of specifying the title. The following example will show the purpose of the descriptors: In his memory, man distinguishes between two objects with the same name not according to a classification or record number, but according to accompanying information or circumstances. One thus identifies two anonymous column capitals in the pantheon (both have the title text "capital" in the CENSUS) according to their position in the portico; two churches with the name "San Marco" conjure up an image in our minds in relation to their location, such as Venice or Rome. In the first case, the descriptor is designed to be a dependent descriptor, as there is nothing more to say about the position "front left". However, "Rome" and "Venice" are linked to "San Marco" by means of a reference, as they are themselves titles to which more information is attached that has nothing to do with "San Marco". For example, Rome can be the location of other churches.

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Relations between titles A single title does not constitute a database. The dataset of a DYABOLA database consists of numerous titles that are related to each other in different ways. Two main types are to be distinguished: sequential-hierarchic and hypotactic. The sequential-hierarchic relations hold the whole database together, and make it into a conceivable set of data, the "database tree". By means of the hypotactic "references", one title can be connected to any other title, similar to the way it is done in the Internet. The database tree arises from the fact that each title can have a "father" and many "children". In the ideal case, this leads to a single tree which has the name of the database as its uppermost title (e.g. Census of Antique …) and branches off downwards via various different subdirectories (such as monuments, documents…), if necessary down to the capitals of a large spa or the quadrants on a codex page. The database tree can be used to present all conceivable hierarchic structures. The references make it possible, to link any particular title with any other particular title, as already mentioned. However, the DYABOLA cross-reference has two decisive advantages over the hyperlink in the Internet, namely it has a clear condition and, if desired, an automatic reference back. A link is inserted by the operator, for example by filling in the "Artist" field under "Object". The operator then looks for the "Person" concerned and makes this selection. The link "Person to Object" under the condition "Artist" has thus already been defined by the database administrator beforehand. This kind of cross-reference always relates to two types of title text (see title text), such as object and person in our example. Of course, two titles with the same type of title text can also relate to each other (for example "Person to Person" under the condition "Father/Mother"). An aquired link is automatically assigned after a link has been inserted. It must be defined once, but separately by the database administrator, because, in contrast to the link, it can have a different name and is not necessarily desirable in all cases. For example, in the aquired link "Person to Object", the different name would be "Works" instead of "Artist". A case in which the reference back is not desirable would, for example, be details of the author in the object dataset. It is good to be able to cite the person entering an object, but it generally makes no sense to fill the details of a person who can also appear as an author of a few interesting monographs with tens of thousands of object datasets.

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Dependent descriptors The dependent descriptors designate the amount of all non-independent descriptors, i.e. all those that are not themselves a title and relate to a reference to the first title. There are two types of dependent descriptor: the "heading" and the "key-word". The latter depend on the former and, whereas the headings must be defined by the administrator, new key-words can be assigned to a heading by the operator. The classifier tree (subject) is a compilation of all conditions. In principle, it is a tree of headings which branch out downwards. The headings and key-words of a database are visible to the researcher, but the tree also contains the entire control of the program invisibly. At the same time, headings of the visible part can also refer to headings in the invisible part (e.g. types of title text). The headings are specified dependent descriptors predefined by the administrator. Like a title, headings can have a "father" and several "children". For purposes of differentiation, one speaks here of levels of the classifier tree, since it functions as the foremost father. Depending on the type of dependent descriptor, it must be decided whether the entry to be made is entered as a heading or as a key-word. Typical headings are specified, particularly hierarchic concept systems, such as the categories of a library system, a classified thesaurus such as Icon-Class, or a clearly limited number of object locations in a museum. In addition, headings can refer to other headings, in order to open up areas of a database which are actually not accessible to the researcher. The key-words are appended to headings of the classifier tree in the form of lists. The name of the respective key-word list is that of the respective heading. The key-words of a list can relate to each other. This makes it possible, for example, to make reference to a synonymous term.

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Comments Comments are independent text fields that can be inserted at different points in the program. They can be used, for example, to more precisely explain a heading in the classifier tree or further specify a descriptor in the title. The comments behave like the title text in relation to the title. They are freely composed texts that can consequently be searched through with the free-text search.

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