release 2.0.0.alpha.7

[Andreas Ronge]

Hi

New release. It contains one new cool featue (issue 181) - combining
cypher DSL with rules.
I have written some documentation about it here, see the Cypher and
Rules section at the wiki page:
https://github.com/andreasronge/neo4j/wiki/Neo4j%3A%3AWrapper-Rules-and-Functions
and how to write Cypher DSL queries -
https://github.com/andreasronge/neo4j/wiki/Neo4j%3A%3ACore-Cypher

Cheers
Andreas

== 2.0.0.alpha.7 / 2012-04-19
* fix for Neo4j::Config bug - did not work from rails to set the db
location, closes #191
* has_n and has_one method generate class method returning the name of
the relationship as a Symbol, closes #170
* Raise exception if trying to index boolean property, closes #180
* Made start_node= and end_node= protected closes 186
* Support for things like dungeon.monsters.dangerous { |m| m[:weapon?]
== 'sword' } closes #181

[Peter Neubauer]

Wow Andreas and friends,
that Cypher DSL does look beautiful!

Cheers,

/peter neubauer

G:  neubauer.peter
S:  peter.neubauer
P:  +46 704 106975
L:   http://www.linkedin.com/in/neubauer
T:   @peterneubauer

If you can write, you can code - @coderdojomalmo
If you can sketch, you can use a graph database - @neo4j

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[Cyprian Kowalczyk]

How do I translate the following query to Cypher DSL:

       Neo4j._query("

         START u=node({user_id}), p=node({place_id}) 

         MATCH 

          u-[:`User#rc`]->rc<-[:`RS#rc`]-rs<-[:`Place#rs`]-p,

          rc<-[:active]-()

         WHERE rc._classname ?= 'RC' 

         RETURN rc", 

         :user_id => self.neo_id,

         :place_id => place.neo_id

       )

[Andreas Ronge]

I have made it a little bit easier to use model object with cypher,
for example added a is_a? method, see
https://github.com/andreasronge/neo4j/issues/193
This make it possible to write the query like this:

Neo4j.query(user, place) do |u, p|
rc = node(:rc)
u > rel(User.rc) > rc < rel(Place.rs) < p
rc < rel(:active) < node
rc.is_a?(RC)
rc
end

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[Cyprian Kowalczyk]

There is one relation missing in your code, should be:

u-[:`User#rc`]->rc<-[:`RS#rc`]-rs<-[:`Place#rs`]-p

and you have

u-[:`User#rc`]->rc<-[:`Place#rs`]-p

Here is my example fully rewritten, if I'm correct:

       res = Neo4j.query(self, place) do |u, p|

         rc = node(:rc)

         rs = node(:rs)

         u > rel(User.rc) > rc < rel(RS.rc) < rs < rel(Place.rs) < p

         rc < rel(:active) < node

         rc.is_a?(RC) 

         rc

       end

I'm using it inside a model so self==user, but Cypher complains with the following error:

NativeException:

       org.neo4j.cypher.SyntaxException: expected node id, or *

       "START n0=node(),n1=node(4) MATCH (n0)-[]->(rc)<-[]-(rs)<-[]-(n1),(rc)<-[]-(v6) RETURN rc"

                                 ^

I'm also wondering why the relation square brackets are empty.

Any ideas?

On 20 kwi 2012, at 14:17, Andreas Ronge wrote:

I have made it a little bit easier to use model object with cypher,
for example added a is_a? method, see
https://github.com/andreasronge/neo4j/issues/193
This make it possible to write the query like this:

Neo4j.query(user, place) do |u,  p|
 rc = node(:rc)
 u > rel(User.rc) > rc < rel(Place.rs) < p
 rc < rel(:active) < node
 rc.is_a?(RC)
 rc
end

[Cyprian Kowalczyk]

https://github.com/andreasronge/neo4j-core/issues/1

[Cyprian Kowalczyk]

All fixed in neo4j-core master.