In the post Fun with Graphs (3): Creating the graph of a database structure, I have presented a small application that creates the graph of a database. We are now going to improve the output by adding the different fields, primary keys, etc.. in the graph.

GraphvizRecordCell

Graphviz supports a type of vertex shape that is drawed as nested tables. This shape is called Record. NGraphviz comes with a class wrapper (GraphvizRecordCell) that lets you easily create such records. Some remarks on cells:

• A GraphvizRecordCell can also contain other nested cells,
• By default, Graphviz starts to arrange the cells horizontally and swith direction (vertical/horizontal) at each level 

Let's take the formatVertex event handler and adapt it to create records:

private void formatVertex(Object sender, FormatVertexEventArgs e)
{
    TableSchemaVertex v = (TableSchemaVertex)e.Vertex;
    GraphvizRecord record = new GraphvizRecord();
    e.VertexFormatter.Shape = GraphvizVertexShape.Record;
    e.VertexFormatter.Record = record;
    GraphvizRecordCell table = new GraphvizRecordCell();
    record.Cells.Add(table);

    GraphvizRecordCell name = new GraphvizRecordCell();
    name.Text = v.Table.Name;
    table.Cells.Add(name);
    ...

Here's a sample result on the MbUnit database: