'"Adds nodes and edges extracted from one table\'s schema
Adds the table name, and the names of other tables found in
constraints, as nodes to the supplied graph.
Adds constraints as edges, pointing from primary to dependent table.
@param table_id: table identifier, as needed by subclass method
get_table_info(table_id).'

def add_table_to_graph(self, table_id):

    (table_name, constraint_iter) = self.get_table_info(table_id)
    self.graph.add_node(table_name)
    for primary_name in constraint_iter():
        if (table_name != primary_name):
            self.graph.add_edge(primary_name, table_name)
