Adding new properties to an existing map

[bi...@levelstory.com]

Is there any way to add additional properties to an existing Map object?

I thought I could use SET, but it doesn't work on maps:

WITH {a: "foo"} AS result

SET result.b = "bar"

RETURN result

Type mismatch: expected Node or Relationship but was Map (line 1, column 31)

Because of this, I'm currently doing this everywhere which makes the queries hard to read:

WITH {a: "foo"} AS result

WITH {a: result.a, b: "bar"} AS result

RETURN result

Thanks,

bill 

[Michael Hunger]

Hey Bill,

interesting what's your use-case for this?

Thanks so much,

Michael

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[bi...@levelstory.com]

Hi Michael,

In order to reduce the number or rows resulting from complex queries, I bundle up the results of sub queries into a Map object.  I then return a collection of Map objects which can then be easily converted into Go structs.  I believe that you were the one that suggested this approach to me.

Here is how I am doing most of my queries:

  MATCH (f:file {id: "foobar"})

  WITH f, {accessedrole: "", accessedby: ""} AS r

  OPTIONAL MATCH (f)-[:CREATED]->(a:activity)

  WITH f, {

    accessedrole: r.accessedrole, accessedby: r.accessedby,

    createdat: a.createdat, createdby: {id: a.contactid, object: "contact"}} AS r

  OPTIONAL MATCH (f)-[:HISTORY]->(a:activity)

  WITH f, {

    accessedrole: r.accessedrole, accessedby: r.accessedby,

    createdat: r.createdat, createdby: r.createdby,

    updatedat: a.createdat, updatedby: {id: a.contactid, object: "contact"}} AS r

  OPTIONAL MATCH (f)-[:TAG]->(x)

  WITH f, COLLECT(x) AS xs, r

  WITH f, {

    accessedrole: r.accessedrole, accessedby: r.accessedby,

    createdat: r.createdat, createdby: r.createdby,

    updatedat: r.updatedat, updatedby: r.updatedby,

    tags: [x IN xs | {id: x.id, object: x.object, name: x.name}]

    } AS r

  RETURN COLLECT({

    id: f.id, object: f.object, projectid: f.projectid,

    no: f.no, name: f.name, description: f.description, url: f.url,

    mime: f.mime, thumbnail: f.thumbnail, size: f.size,

    accessedrole: r.accessedrole, accessedby: r.accessedby,

    createdat: r.createdat, createdby: r.createdby,

    updatedat: r.updatedat, updatedby: r.updatedby,

    tags: r.tags

  }) AS r

[Michael Hunger]

Hmm,

what you could do instead of modifying the map in-place to create the new map with the additional data around the original one:

e.g.

WITH {a: "foo"} AS result

RETURN {inner: result, b: "bar"} AS result

We're also looking into a feature like:

SET map.key = value

But I can't give any timeline for that right now.

Cheers, Michael

[bi...@levelstory.com]

Yes, I thought about that but then I would need to unpack everything again before I return the results.  Being able to do SET map.key would be ideal, I guess I'll just wait until that becomes available.  

[Jason Brumwell]

I also would love this feature :)

[Michael Hunger]

You can do it with the apoc procedures

There is eg apoc.map.setKey

Von meinem iPhone gesendet