CreatedAt and UpdatedAt with custom Id

Drivers & Stacks Spring Data Neo4j & Neo4j-OGM
,
1

I want to maintain createdAt and updatedAt fields in my entity, while using a custom ID instead of an auto-generated one.

2

You can create a property for that (I have one called uuid across all my nodes), create an index if you want it to be unique - it will depend on your graph how "unique" you need it to be.

CREATE CONSTRAINT <unique_identifier_name>
  FOR (n:<Label>)  
  REQUIRE n.<property> IS UNIQUE;

When you are working with your nodes, you can use code similar to the following (you need at least your ParamId property - I also keep track of the Uuid of the agent creating).

  MERGE (n:Node { uuid: $ParamId })
// this happens when you create the node
    ON CREATE 
      SET n.createdAt = timestamp(), 
          n.updatedAt = timestamp(),
          n.createdBy = $CreatedBy
// this happens when you update the node
    ON MATCH 
      SET n.updatedAt = timestamp(), 
          n.updatedBy = $CreatedBy
3

no like,
I have Car object

public class Car{


    @Id
    private Long carId;

    private String name;
    @CreatedDate
    private LocalDateTime createdAt;

    @LastModifiedDate
    private LocalDateTime updatedAt;
}

here for carId i have my own id's
so here i want to get audit of createdAt and updatedAt

4

You can map whatever Java properties are used for your Cypher query. Those are the variables with $ in my example.

5

but if i want to do it for many objects with many fields it will be difficult,
I was looking for more generic approach

6

You can dynamically build queries in your Java (no matter how many properties your objects/nodes have. You will need to create a mapping mechanism to work that out.

something like:

---
[prop1] --- [$prop1]

7

You just have to provide the a @Version annotated property (SDN Reference | Version). With this, SDN can keep track of the object and determine if the entity is new or was updated on save.

8

@gerrit.meier
That’s great, it's working now!

Currently, if I use findById to retrieve an object, make data changes, and save it back, the createdAt and updatedAt timestamps are working fine. However, what if I don’t want to use findById and just directly create an object with a known ID, regardless of whether the ID already exists or not?

If the ID exists, only the updatedAt timestamp should be updated. But if the ID doesn't exist, the createdAt timestamp should also be updated.

9

This sounds like a bad practice in general. I would advise to also do a query upfront for an optional existing entity here. From there you could either create a new instance or use the returned one for modification.
In you case, SDN cannot determine before the update/save operation, if the object already exists because it does not have the version hint. As a consequence, this object will always be treated as new and overwrite the created data.