cypher foreach and complex queries

[Mat Tyndall]

I'm having problems using foreach to create unique and set the new nodes.

Here's a simplified example of what I'm trying to do:

query:

START movie = node(0)  

FOREACH(a in {ACTORS} :

CREATE UNIQUE movie-[:CAST {characters: HEAD(a)}]->(actor HEAD(TAIL(a)))

SET actor.id = COALESCE(actor.id?, LAST(a)))

params = {

  ACTORS : [["Neo", {name: "Keanu"}, 1234]]

}

In the foreach statement I can do the create unique part just fine, but I also want to set an actor.id if it doesn't exist. The problem is that SET doesn't seem to recognize actor. Is this because multi part commands inside a foreach aren't allowed or is it something else? Splitting this into multiple foreach statements isn't practical because there's no good way to sync the actor.id paramater with the right node (maybe with a WHERE, but that'd be really messy).

Also, the foreach documentation is missing SET in it's list of approved commands.

Thanks,

-Mat

[Mat Tyndall]

Going to post this in issues.

Fails:

start n=node(*) foreach(m in [1,2,3] : 

                        create unique n-[:test]->(o {name: 'test' + STR(m)}) 

                        set o.id = COALESCE(o.id?,m)) 

match n-->m 

return m

Works:

start n=node(*) foreach(m in [1,2,3] : 

                        create unique n-[:test]->(o {name: 'test' + STR(m)})) 

match n-->m 

return m

[Andres Taylor]

Hi Mat,

I pushed a fix for this a couple of days ago. Have you tried this on a recent snapshot?

Andrés

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[chuwiey]

Hi,

Related to this I think... > A query to add unique movies (by url) to the db

I tried:

START me=node(1), i=node:node_auto_index(type='item')

FOREACH (new_movie in {movies}:

    CREATE (new_movie)

    WHERE NOT(new_movie IN i.url))

RETURN new_movie

Running latest snapshot: Neo4j - Graph Database Kernel 1.9-SNAPSHOT (revision: 1.8.M07-147-g84d07a2)

Error: `)' expected but `W' found

Thanks

[Michael Hunger]

this is not a valid syntax:

FOREACH (new_movie in {movies}:

    CREATE (new_movie)

    WHERE NOT(new_movie IN i.url)

you have to filter movies instead:

FOREACH (new_movie in filter(m in {movies} WHERE NOT(new_movie IN i.url))

    CREATE (new_movie))

Michael

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