try (Transaction tx = graphDb.beginTx())
{
boolean result = checkIfKnowsEdgeExists(startNode, endNode));
if (!result) {
makeKnowsEdge(startNode, endNode);
tx.success();
}
should do it. you can't deadlock against yourself if you only create one
transaction ;)
- Lasse
On Thu, Jul 3, 2014 at 1:09 PM, Frandro <[email protected]> wrote:
> the parameters are a start node and end node.
>
> I'd like to check there's an edge named 'KNOWS' between them and connect
> them with the edge.
>
> It's written in my java code as follows.
> Transaction tx = graphDb.beginTx();
> boolean result = checkIfKnowsEdgeExists(startNode, endNode));
> tx.success();
> tx.close();
>
> if (!result) {
> Transaction tx = graphDb.beginTx();
> makeKnowsEdge(startNode, endNode);
> tx.success();
> tx.close();
> }
>
> The problem of the code above is it can be performed in 2 transactions.
> I'd like to perform it in one transaction for performance, which creates
> an edge when there's no such an edge.
> Is there any better way to solve it? Cypher does not matter.
>
> The following code throws a deadlock related exception.
> Transaction tx = graphDb.beginTx();
>
> boolean result = checkIfKnowsEdgeExists(startNode, endNode));
>
> if (!result) {
> Transaction tx = graphDb.beginTx();
> makeKnowsEdge(startNode, endNode);
> tx.success();
> tx.close();
> }
>
>
>
>
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