Papers in PDF format

following, we discuss basic types of documents and special cases.
6.1 Document Types
``Stand-alone'' document:
In the simplest case of a table containing no references to other tables and not being referenced by any other
table, each entry in the database (a record in a table) is translated into a HTML file containing a title, the names
of the fields and their values. A sample document is shown in [Fig. 3a]. If any label text has been supplied in the
catalog table Columns or by additional user input, this text is used as the label for a field; otherwise, the column
name is used for this purpose.
References between tables:
This more interesting case is depicted in [Fig. 3b] which shows a web page consisting of two parts separated by a
rule. Consider a web page for a piece of music: the upper part contains instance data and links to parents. A
parent table is a table that is referenced by another table:
the second field in the upper part (ComposerID of table Piece) of Fig. 3b] contains a link that points to a parent
(an entry in the table Composer), in this case the composer of the piece. A link to the corresponding web page is
provided together with the value (possibly expanded, see sec. 6.2).
The lower part shows a list of children of this piece, i. e. a list of recordings. We use the expanded keys to
represent the children. Note that in the case of 1:n-relationsships a parent can have several children.
Fig. 3: A generated stand-alone document (a) and a document with references (b)
When automatically generating hypertext from database data, we encountered several problems which seem to persist
across different application domains. We show those of the problems we have solved in the following sections.
6.2 Key Expansion
Consider the table Piece: each entry references an entry in the table Composer via the field ComposerID. In many cases
this would be a unique number for each composer (an artifical key). In the table Piece this key is contained in the
referencing field. Obviously, the resulting web page would not look satisfying, since seeing e. g. the number 42 in the
field ComposerID does not tell much; the user would have to follow this link to see what the number stands for.