Multi-valued field indexing

[dbeaumon]

Is it possible to apply an index to a list of (string) values, so that you can efficiently look up "all nodes with a list property that contains X".

I have tried creating the index, and adding a list of strings, but any cypher search I do either returns nothing, or the profile shows the results are obtained via a label scan and not the index.

If it is possible:
a) Does the CREATE INDEX statement need to do anything special?
b) What does the MATCH statement look like?

Thanks,

Dave

[andrew_bowman]

Currently this kind of lookup isn't supported with schema indexes. We would advise remodeling these as connected nodes to your main node.

For example, if you had something like:

(:Sentence {id:12345, words:['sphynx', 'of', 'black', 'quartz', 'judge', 'my', 'vow']})

We would advise you to remodel such that:

(:Sentence {id:12345})-[:HAS_WORD]->(:Word {word:'sphynx'})

and so forth with a separate :Word node per word, and an index on :Word(word) for quick lookup.

Your :Word nodes would be reused with other :Sentence nodes so you could find similar sentences with the same words:

MATCH (w:Word)<-[:HAS_WORD]-(s:Sentence)
WHERE w.word = 'quartz'
RETURN s

[michael_hunger]

Array indexes only find the full array.
You can use a manual index via APOC for that (which indexes each array entry),
or better the new fulltext index for 3.5.

[dbeaumon]

Thanks. APOC was going to be plan B, but the additional manual index maintenance was a headache I didn't really want for a solution to an edge case that I'm hoping will never happen. I'm going to give 3.5 a try - it's about time I took a look.

I assume that the Neo4JRule TestRule code (Java) for 3.5 supports this new indexing for my testing entertainment?

[michael_hunger]

The new indexes are managed via procedures, so i don't see why not.

[clem]

I tried searching but it's not clear to me if APOC full text search can work on an list of strings. It would be nice if it did.

E.g. If I have a person with nicknames, can I do an APOC full text index and search on the list of nicknames? (I understand the built-in indexing property indexing won't work.)

CREATE (p:Person {name:"Elizabeth", nicknames: [
  "Lizzy", "Liz", "Beth", "Betsy"]})

Thanks in advance.

[michael_hunger]

The old 3.x indexes supported multi-value arrays/lists as properties. None of the current indexes do. There are a number of feature requests for it but nothing has been decided yet.

[clem]

Is that true for both standard indexing and full text indexing?

Thanks.

[michael_hunger]

Yes, true for both types of indexes

[frederico_braga]

Thanks, any updates on these feature requests?

[andrew_bowman]

No changes at this time on this one, though there are other index changes coming down the pipeline.