Basic Structure
A ISO 2709 record has three sections:
- Record label—the first 24 characters of the record. This is the only portion of the record that is fixed in length. The record label includes the record length and the base address of the data contained in the record. It also has data elements that indicate how many characters are used for indicators and subfield identifiers. (See Variable fields, below)
- Directory—the directory provides the entry positions to the fields in the record, along with the field tags. A directory entry has four parts and cannot exceed nine characters in length:
- Field tag (3 characters)
- Length of the field
- Starting character position of the field
- (Optional) Implementation-defined part
- Datafields (Variable fields)—a string containing all field and subfield data in the record
- Record separator—a single character (IS3 of ISO 646)
Note that although tags are often displayed as labels on bibliographic fields and each bibliographic field has an associated tag, the tags are stored in the directory not in the bibliographic field.
Read more about this topic: ISO 2709
Famous quotes containing the words basic and/or structure:
“The basic difference between classical music and jazz is that in the former the music is always greater than its performance—Beethoven’s Violin Concerto, for instance, is always greater than its performance—whereas the way jazz is performed is always more important than what is being performed.”
—André Previn (b. 1929)
“The philosopher believes that the value of his philosophy lies in its totality, in its structure: posterity discovers it in the stones with which he built and with which other structures are subsequently built that are frequently better—and so, in the fact that that structure can be demolished and yet still possess value as material.”
—Friedrich Nietzsche (1844–1900)