Question: I'm using an oracle table. Let's pretend I have a simple table that has names and datetimestamps:

```
Name  Time
---   ---
joe   01JAN1970:00:00:01
jane  04MAR2010:20:55:11
julie 22DEC1984:11:11:11

```

I want to add a third column. Let's call it date. I want to truncate off the time. 

```
Name  Time               Date
---   ---                ---
joe   01JAN1970:00:00:01 01JAN1970
jane  04MAR2010:20:55:11 04MAR2010
julie 22DEC1984:11:11:11 22DEC1984

```

That could be accomplished easily enough with an update. The trick is, if someone updates julie's Time, I want her Date to automatically update as well:

```
Name   Time               Date
---    ---                ---
joe    01JAN1970:00:00:01 01JAN1970
jane   04MAR2010:20:55:11 04MAR2010
julie  02OCT1999:22:22:22 02OCT1999

```

Is there a simple way to accomplish this with Oracle 11G? Can I set up a trigger to update another column in a row when a certain column changes?

Edit: clarity in example

Answer: 
`created` is the wrong concept. You have a set of nodes in the "from" graph, and you're creating a set of *new* nodes in the "to" graph. `created.add(copyTo)` will add a new node, from the "to" graph, to the set. But when you go through `created.iterator` to see if a node is already there, you're looking for a node from `copyFromNeighs`, which is a node in the "from" graph. It looks to me like this will never succeed. Or else the result will be that you'll have nodes in the "to" graph pointing to nodes in the "from" graph.

Basically, I believe you need `created` to be a `HashMap<Vertex,Vertex>`, not a set. The "key" of the `HashMap` would be a node in the "from" graph, and the "value" would be the corresponding node in the "to" graph. Then, when you look at the neighbors of a "from" node, you get the corresponding "to" node (if it's already been copied) from the map, and add that to the neighbors of your newly created "to" node.
you need more consistent way to map source vertices onto resulting vertices. Declare `created` as hashmap, not hashset. Create new vertex only when `created.get(oldVertex)==null`.