UUIDs do not match with deep insert and composition

[aschmidt93]

Description of erroneous behaviour

When using a deep insert to create a parent entity (UUID as key) and its child via composition, the child will not have the generated UUID of the parent as its backlink but instead a random one.

I'm not sure whether this is a db layer or service layer problem. Here, @cap-js/postgres is used.

Detailed steps to reproduce

Service & entity:

using { cuid } from '@sap/cds/common';

service MyService {
    entity Parent : cuid {
        name : String;
        child : Composition of one Child;
    }

    entity Child {
        key parent : Association to one Parent;
        name : String;
    }
}

Request:

"POST /Parent"
{
  "name" : "foo",
  "child" : {
    "name" : "bar"
  }
}

Result:

    {
      "ID": "6202fa47-8105-4bb9-b002-a6208ae8c80b",
      "name": "foo",
      "child_parent_ID": "80a2f386-3fa5-47f4-82dc-1e2ae9a3a075",
    },

Details about your project

| @cap-js/asyncapi | 1.0.2 |
| @cap-js/cds-typer | 0.32.1 |
| @cap-js/cds-types | 0.9.0 |
| @cap-js/db-service | 1.17.2 |
| @cap-js/hana | 1.6.1 |
| @cap-js/openapi | 1.1.2 |
| @cap-js/postgres | 1.11.1 |
| @sap/cds | 8.7.1 |
| @sap/cds-compiler | 5.7.4 |
| @sap/cds-dk | 8.7.1 |
| @sap/cds-fiori | 1.3.0 |
| @sap/cds-foss | 5.0.1 |
| @sap/cds-mtxs | 2.5.1 |
| @sap/eslint-plugin-cds | 3.1.2 |
| Node.js | v20.15.0 |