This tutorial explains how to create RDF instance data using
RDFAuthor. We'll be creating data about Dan Brickley using the
foaf schema. This isn't detailed documentation, but should
get you started.
Note: These screenshots are out of date, but this tutorial
is still correct. Some icons have been added to the toolbar which
are irrelevant to what follows
This will present you with an empty document. The toolbar
items have tooltips, so have a look at what they do if you
Open Dan's Homepage
We'll be grabbing most of our information from
open it in OmniWeb. I say 'Omniweb' because Explorer doesn't
seem to type dragged URLs properly - something we need.
Open The Schema Window
The schema window is under the 'Tools' menu, or can be opened
using 'alt-apple-s'. It comes with several useful schemas
ready to be loaded. Import 'http://xmlns.com/foaf/0.1/' since
that's all we'll be using. Once imported you'll see that there
are now entries under 'Node Types' and 'Connection Properties'
(foaf has both).
Creating a 'foaf:person' Node
We want a person to hang properties of, so open the foaf entry
under 'node types' and drag 'Person' onto the big empty white
rectangle in the document window.
This will create an anonymous resource node of type
'person' at the point you dragged to. It's red because it is
the currently selected item. Turn on all the display options
(three buttons on middle of toolbar) so that you can see
that the node is anonymous and has type 'Person'.
Adding Dan's Homepage to the Model
Move to Omniweb. Drag the url for the page into the model.
You will now have a node with the id of Dan's homepage,
but a genric type: resource.
This should be a foaf:Document, so drag 'Document' from
the schema window onto the newly created node. This will add
a type to the node.
Adding the Literal "Dan"
This is pretty simple. Drag the text 'Dan' from Omniweb into
the model. This creates a literal node containing 'Dan'. By
selecting different nodes you'll see that resources are green,
whereas literals are yellow. The currently selected item is
red. You can select and move nodes using the 'Select and Move'
mode in the toolbar (surprise). Tab and shift-tab also select
items in the order (and reverse order, respectively) that they
were added to the model. Incidently, the reason for not using
Explorer is that it treats URLs like strings, so dragging URLs
produces literals containing the URL - not what you want. This
is simple to fix (using the info window - see below), but a
Add More Nodes
You should now be able to add other information, and type it
accordingly, from the web page.
We now need to connect our subject (the anonymous 'Person') to
all the information we have about Dan. Select the 'Add
Connection' mode in the toolbar. Drag connections from the
'Person' to each of the other nodes. This creates connections
(without properties) with the 'Person' as the subject, and the
node pointed to as the object.
Adding Properties to Connections
We now need to state what kind of relation (property) our
object bears to the subject. Open the foaf connection
properties in the schema window. Drag the relevant properties
onto each of the new connections, eg 'mbox' for the
connections pointing to Dan's email addresses, 'firstName' for
the connection pointing to the 'Dan' literal.
The Final Model
We've now pretty much finished. Hopefully you've got something
much like the image below.
Manually Adding Data
There is, of course, plenty of data that isn't contained in
Dan's homepage. For example, I happen to know that Dan uses
the irc nick 'danbri'. We can add this by creating a new node
and connecting with a 'nick' connection.
The new node is completely wrong. It is an anonymous
resource, whereas we want a literal 'danbri'. Select the
offending node and open the info window (apple-shift-I), or
simply double click on the node. This will open a window
which displays information about the currently selected
item. We want this to be a literal, so select 'Change to
literal' and press 'Change' (or press return).
Next we want the content of the literal to be 'danbri',
so enter 'danbri' in the 'Content' field, and select
You can look at the XML/RDF serialisation of this model by
clicking on the 'Toggle View' item in the toolbar. This
replaces the graphical view with a text view containing the
XML representation. You can't edit the model in text, but you
can copy text from the preview.If there are any errors,
however, a dialog box will pop up - see the next section for
Dealing with Errors
RDFAuthor attempts to prevent you making broken rdf - but it
isn't perfect. Problems may show up on preview or export. To
check for them click the 'Check Model' item in the toolbar
(it's a big 'tick' icon). If there are any errors or warnings
it will tell you and open a window containing a summary of the
problems. Double-clicking on entries will select the problem
item, and open the info window so that you can edit the item
Below I've added some two errors into the model (a
connection with no property, which also begins at a
literal), and one change which will raise a warning
(one literal is empty).
Saving and Exporting
You can save RDFAuthor models just as you would any other
document. You can also export the model as xml/rdf using the
'Export As' item in the file menu. Select the 'RDF/XML
Document' option'. This will not work if the model has any
errors (but it will tell you that export failed).
Last modified: Thu Nov 08 20:36:05 GMT 2001