Assign label to Lightweight Edge from command line

[Riccardo Tasso]

Hi, if I tried the following command:

CREATE EDGE FROM #14:1 TO #14:0 SET @label="myLabel"

But it seems to create a new record in class E.

What if I would create a new lightweight edge from command line?

I'm using orient 1.7.10.

Cheers,

   Riccardo

[Luigi Dell'Aquila]

Hi Riccardo,

what TinkerPop calls labels is represented by OrientDB classes. 

You can create a lightweight edge of a particular class with this syntax:

CREATE EDGE MyLabel FROM #14:1 TO #14:0

Of course the class MyLabel has to exist and has to extend E

If you use the SET labelName = value, the labelName will become a property of the edge, so the edge will become a regular one (not lightweight)

Luigi

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[Riccardo Tasso]

Thank you Luigi,

in this case is there a command to list all the existing "classes" extending E?

The command CLASS doesn't list lightweight edges, since they're not real classes.

Cheers,

   Riccardo

[Riccardo Tasso]

Sorry I was talking about CLASSES command.

The point is the following.

Under the hood lightweight edges ARE NOT instances of a class.

When I created my database from Java API, I didn't create any class for my edges.

I need to create e new edge from command line.

1) I am forced to add a new class, while for all the previous edges I didn't have to do this (also if there are already other edges with the same label) => this is somehow inconsistent, since it means at the end I will have some lightweight edges for which there exists a class and others without!

2) The new created class will remain empty, since a new edge isn't a new record => this means the new class I created is unuseful

I don't remember exactly if there can be a mixed model graphdb (with lightweight AND non-lightweight edges) but I would suggest the following behaviour for ADD EDGE myLabel FROM #1:1 TO #1:2:

• IF myLabel extends E AND non-lightweight THEN as usual
  
• IF myLabel IS NOT A CLASS AND lightweight THEN add the lightweight edge

It would also be very useful a command to list all the edge types, which is different from listing all the classes extending E. I don't know if this requires to scan all records or a list of lightweight edges is maintained elsewhere.

My two cents,

  Riccardo