Java, what version are you using?
2.0 final?
Michael
Am 21.01.2014 um 17:29 schrieb Javad Karabi <karabija...@gmail.com>:
> from what I can tell, if there where clause is ">" or "<" (as it is in the
> actual query which i am using, not in this example query...) then the WHERE
> predicate _is in fact_ a filter, applied _after_ the match. It looks to me
> that "TraversalMatcher()" does not apply predicates which involve > or <, but
> instead delegates this to "Filter()" after the fact, which does not correlate
> with what is stated on the documentation.
>
> On Tuesday, January 21, 2014 10:25:41 AM UTC-6, Javad Karabi wrote:
> (c:Customer)-[:ordered]->(p:Product)-[:category]->(:Category)
>
> Now, say that there are 2:
> c-[:ordered]->(:Product { name: "pants", quantity: 10})
> c-[:ordered]->(:Product { name: "shirt", quantity: 5})
>
> Now, say that if I only want to cross the category relationship if the
> p.quantity > 6
>
> In the most basic way, I would do:
>
> (c:Customer)-[:ordered]->(p:Product)-[:category]->(cat:Category)
> WHERE p.quantity > 6
>
> However, I figured that maybe neo4j would (non-optimally) traverse the entire
> path _then_ filter where on top of the path.
>
> So what I did was:
>
> MATCH (c:Customer)-[:ordered]->(p:Product)
> WHERE p.quantity > 6
> WITH p
> MATCH p-[:category]->(cat:Category)
>
> This, I figured, would then allow neo4j to cross out to all the product
> nodes, as I would need them anyway in order to filter out the ones which have
> a quantity of less than 6.
>
>
> Now... finally to my question.
> The following URL:
> http://docs.neo4j.org/chunked/stable/query-match.html
> states that:
> WHERE defines the MATCH patterns in more detail. The predicates are part of
> the pattern description, not a filter applied after the matching is done.
>
> So, my question is, if the predicates (specifically p.quantity > 6) are part
> of the pattern description, and _not_ applied _after_ matching (therefore
> applied before or during), then cutting the query with the WITHs would be a
> moot point
>
> So, I would think that
>
> (c:Customer)-[:ordered]->(p:Product)-[:category]->(cat:Category)
> WHERE p.quantity > 6
>
> would be sufficient, , as neo4j _would not_ actually traverse to cat, since
> it would apply the filter during the match process.
>
> However, in practice, I notice that using WITH is actually faster. Is there
> any possible reason for this?
> It may be necessary for me to show my query exactly, I also have the profile
> data for the query, which I am currently analyzing
>
> --
> You received this message because you are subscribed to the Google Groups
> "Neo4j" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to neo4j+unsubscr...@googlegroups.com.
> For more options, visit https://groups.google.com/groups/opt_out.
--
You received this message because you are subscribed to the Google Groups
"Neo4j" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to neo4j+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/groups/opt_out.
