Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>What do you mean, you can't subclass out vertices? You can use your own vertex class, it's just a matter of specifying it in the Graph typedef. You can even use members as properties when working with BGL algorithms.</p> <p>As for the other way around (which is harder IMO), you need to create a vertex property list and access it using a vertex descriptor... I think.</p> <p>Edit: You specify vertex/edge classes when defining your graph type:</p> <pre><code>struct Vertex { double some_property; }; struct Edge { double weight; }; typedef boost::adjacency_list&lt; boost::listS, boost::vecS, boost::undirectedS, Vertex, Edge &gt; Graph; //sorry about the formatting Graph g; </code></pre> <p>From where on g[vertex_descriptor] should return a reference to Vertex, e.g.:</p> <pre><code>//add 100 vertices for (int i=0; i&lt;100; ++i) { Graph::vertex_descriptor v = add_vertex(g); g[v].some_property = -1.0; } //zero some_property for all vertices for (Graph::vertex_iterator i = vertices(g).first; i != vertices(g).second; ++i) { g[*i].some_property = 0.0; } </code></pre> <p>I couldn't find my visitor code making use of these properties but I did find the relevant part of the BGL documentation:</p> <p>1) The part about <a href="http://www.boost.org/doc/libs/1_39_0/libs/graph/doc/using_adjacency_list.html#sec:adjacency-list-properties" rel="noreferrer">Internal Properties</a>, which recommends you use instead:<br> 2) <a href="http://www.boost.org/doc/libs/1_39_0/libs/graph/doc/bundles.html" rel="noreferrer">Bundled Properties</a></p> <p>The second link seems to have a Boost function making use of bundled properties using a member pointer.</p> <p>Does this help?</p>
    singulars
    1. This table or related slice is empty.
    1. POBoost Graph Library and Visitors
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USaib
    1. USaib
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POBoost Graph Library and Visitors
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COReally? I'm looking for documentation on this and I can't find much - could you give a short example where you provide a custom vertex class, as opposed to tacking properties onto vertices instead?
      singulars
      1. PO
      1. This table or related slice is empty.
    2. COI had problems with the documentation, too. I'll post a code sample as soon as I get home.
      singulars
      1. PO
      1. USaib
    3. COIt does - I ended up taking a similar approach in one attempt on the problem. The only problem here is that I also needed to access the vertex information from the element's properties as well, which involved keeping track of the element's own vertex_descriptor and routing all requests for connectivity info through the descriptor. It ended up being fairly complicated, and I'm fairly certain now that I'm better off writing a small graph implementation myself. Thanks though, when I use this library in the future for other things bundled properties are definitely the way to go!
      singulars
      1. PO
      1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload