Support DynamicProperties [DATAGRAPH-555]

[spring-projects-issues]

Luanne Misquitta opened DATAGRAPH-555 and commented

Currently SDN 3 has support for persisting DynamicProperties (i.e. using a property map).

http://docs.spring.io/autorepo/docs/spring-data-neo4j/2.3.0.M1/api/org/springframework/data/neo4j/fieldaccess/DynamicProperties.html

At least one client wants this to be supported

---

Affects: 4.0 M1

Attachments:

• features.png (12.92 kB)

25 votes, 20 watchers

[spring-projects-issues]

Luanne Misquitta commented

Original github issue comment from Vince:

It seems that the idea is to extend the schema-flexible nature of Neo4j all the way into the entity model, so that whatever is in the graph is available on the entity objects (regardless of what it is or how it got there), and vice versa: any attributes set (changed / removed) on the entity objects would always get persisted in the graph. The primary purpose of this feature is to avoid having to make code changes to entity objects as the underlying graph changes.

Some thoughts:

Support for relationships with properties (@RelationshipEntity) might be tricky: One day a relationship might have no properties, the next day it might have a timestamp attribute. Does this imply dynamically creating these domain entities depending on their "shape" ?

Maybe the requirement would be better served by exposing the underlying Node and Relationship objects via a simple API and let the client decide how to construct its entity model. We already have these objects in the OGM layer, so we should be able to wrap them via API calls:

List<Node> getGraph()
setGraph(Node node)
Some examples from a real requirement would be useful to help start our thinking about this

[spring-projects-issues]

Vince Bickers commented

One possible implementation:

@NodeEntity Person {

    @GraphId
    Long id;

   String name;

   @PropertyMap
   Map<String, String> otherProperties;

}

For the sake of simplicity, the @PropertyMap annotation would only support String->String mapping

[spring-projects-issues]

Jim Gallagher commented

I don't have any technical assistance to offer, but I'd like to say that this feature is what attracted me to Spring Data Neo4J in the first place, and is the single thing stopping me upgrading to 4.0 - I'd really love it if it could be prioritised.

[spring-projects-issues]

Luanne Misquitta commented

Jim, can you briefly describe your use case, including how you use dynamic properties (persist/load only, through custom cypher queries as well etc.)? This feature is on the roadmap, some concrete use cases will help us determine what kind of support to provide. Thanks

[spring-projects-issues]

Jim Gallagher commented

Happy to.

The system I'm building is a data dictionary, with a defined node & relationship structure, but a very fluid property structure on the nodes - 2 nodes of similar type could have no similar properties, or all similar etc. New properties can & will be added, others edited and/or deleted.

Hence a dynamic property approach is a must - specifically defined classes will not work in this case.

It's possible that these properties may be accessed through custom cypher, as we're migrating from a managed-extension approach.

Does this assist, or can I clarify further?

[spring-projects-issues]

Luanne Misquitta commented

Thanks Jim

[spring-projects-issues]

Nikolay Gorylenko commented

"arbitrary properties" promise is on project homepage http://projects.spring.io/spring-data-neo4j/ , as first feature:

!features.png!

But since v4 property-based graph turned into OGM, killing all schema-less use cases

[spring-projects-issues]

Jim Gallagher commented

@Nickolay, have you a link that says this is definitely killed? I've not seen anything that would indicate that.

@All, please note that my idea of this feature was only on nodes, not relationships

[spring-projects-issues]

Luanne Misquitta commented

@Jim, @Nickolay, this has not been killed, as you can see the issue is still open and to be prioritized. This page http://projects.spring.io/spring-data-neo4j/ hasn't been updated and still talks about SDN 3 features

[spring-projects-issues]

Eagle commented

Hello,
I did a proof of concept about a year and a half ago using Spring Data Neo4j 3.x and I really liked it.
Few weeks ago I finally started the project and I decide to go with Spring Data Neo4j 4.x as it seems easier to put in place. I just arrive today on the part I required to map some dynamic properties in the database and realized it is not yet available in SDN4.
I hope you have this feature planned in a near future in your backlog, otherwise I will have to downgrade my project to use SDN3 and the way I use the database is better suited to SDN4.

My use case is very similar to Jim's use case. I have a specific class where the list of properties can vary from an instance to another and using the dynamic properties is just perfect.

Thanks for your great work.

Note: I'm currently using SDN 4.1.0-M1 (as I require a remote DB for production but an embedded DB for automatic tests) and despite the missing feature it is working well.

[spring-projects-issues]

Nikolay Gorylenko commented

@Eagle, welcome aboard :) - i'm on the same boat.
It is not always safe to bet on feature, even if it is listed as #1 on project's homepage

[spring-projects-issues]

Eagle commented

@Nikolay, in fact I didn't look at the feature list of the version 4 initially (my fault), and I was very interesting on that new implementation so I go forward. No I have three options: a) going back to version 3, b) waiting on the feature that is low in the backlog (we all know what it means) or c) finding a way to work without the feature. For sure I will not go back, in fact, I already implement such complex model 10 years ago on SQL database, I just hoped never to do it again: I will progress with option c (at least to provide some capability to provide the project is viable) until the feature is in

[spring-projects-issues]

Sivaprasad Sreenivasan commented

Hello Team, is this planned to be fixed in any of the upcoming releases?

[spring-projects-issues]

Rubin Simons commented

Hi Team,

This feature is critical for us (6 peeps dev-team working on rather big Neo4j + SDN app). We're currently camping on 3.x and can't move to the greener grass on the 4.x side due to no support for dynamic properties; Is there any movement on this?

Kind regards

[spring-projects-issues]

Daniel Murygin commented

We have stopped the development of a prototype because we can not wait longer for this feature: https://github.com/murygin/v2020

Therefore we can not use Neo4j anymore. What a shame! Back to MySQL / Maria DB... :(