lb3 - Relations on uuid

[fasenderos]

Steps to reproduce

When the foreignKey of the relations point to ID everything works as expected, while if I try to point the foreignKey to UUID, the UUID is parsed as integer (NaN) and the relation not work.

To reproduce create 2 models:

Customer

{
  "name": "customer",
  "base": "PersistedModel",
  "idInjection": true,
  "options": {
    "validateUpsert": true
  },
  "properties": {
    "id": {
      "type": "number"
    },
    "uuid": {
      "type": "string",
      "defaultFn": "uuidv4"
    },
    "name": {
      "type": "string"
    }
  },
  "validations": [],
  "relations": {
    "addresses": {
      "model": "address",
      "type": "hasMany",
      "foreignKey": "customerId"
    }
  },
  "acls": [],
  "methods": {}
}

Address

{
  "name": "address",
  "base": "PersistedModel",
  "idInjection": true,
  "options": {
    "validateUpsert": true
  },
  "properties": {
    "id": {
      "type": "number"
    },
    "uuid": {
      "type": "string",
      "defaultFn": "uuidv4"
    },
    "customerId": {
      "type": "number",
      "mysql": {
        "columnName": "customer_id"
      }
    },
    "customerUuid": {
      "type": "string",
      "mysql": {
        "columnName": "customer_uuid"
      }
    },
    "street": {
      "type": "string"
    }
  },
  "validations": [],
  "relations": {
    "customer": {
      "model": "customer",
      "type": "belongsTo",
      "foreignKey": "customerId"
    }
  },
  "acls": [],
  "methods": {}
}

Get customer with address related by ID:

const customer = await app.models.Customer.findById(1, {  include: { relation: 'addresses' } });
console.log(customer);

Now in Address replace "foreignKey": "customerId" with "foreignKey": "customerUuid" and you get customerUuid as NaN:

If you do the same thing for Customer model by replacing the "foreignKey": "customerId" with "foreignKey": "customerUuid", you get an empty addresses list

Expected Behavior

The ability to use UUID on to relate model

Additional information

Node: v10.14.1
Npm: v6.4.1
Database: 10.1.30-MariaDB

lb --version
5.0.3 (generator-loopback@6.1.1 loopback-workspace@5.0.0)

"dependencies": {
    "compression": "^1.0.3",
    "cors": "^2.5.2",
    "helmet": "^3.10.0",
    "loopback": "^3.22.0",
    "loopback-boot": "^2.6.5",
    "loopback-component-explorer": "^6.2.0",
    "loopback-connector-mysql": "^5.4.2",
    "serve-favicon": "^2.0.1",
    "strong-error-handler": "^3.0.0"
  }

[fasenderos]

Maybe here is same issue on LB4 loopbackio/loopback-next#3602 that seems to be solved

[bajtos]

Thank you for reporting the issue. Since it's related to LoopBack 3.x, I am going to move it to strongloop/loopback repository.

[bajtos]

Maybe here is same issue on LB4 loopbackio/loopback-next#3602 that seems to be solved

This looks like a reasonable assumption to me. Can you try to apply loopbackio/loopback-datasource-juggler#1783 to the juggler module installed in your dependencies and then add useDefaultIdType: false to uuid property definition?

[fasenderos]

Thank you for your reply.
I replace in loopback-datasource-juggler/lib/datasource.js on line 711
if (idProp && idProp.generated && this.connector.getDefaultIdType)
with
if (idProp && idProp.generated && idProp.useDefaultIdType !== false && this.connector.getDefaultIdType)

Then edited Customer and Address models as below:

### Customer and Address
"uuid": {
   "type": "string",
   "useDefaultIdType": false,
   "defaultFn": "uuidv4"
}

### Address
"customerUuid": {
    "type": "string",
    "useDefaultIdType": false,
    "mysql": {
      "columnName": "customer_uuid"
    }
}

But I get same results, uuid NaN.

[bajtos]

Hmm, then the problem may be somewhere else.

[fasenderos]

The juggler always look at the id prop, so adding "id": true to uuid property make the relation work again:

"uuid": {
   "type": "string",
   "id": true,
   "useDefaultIdType": false,
   "defaultFn": "uuidv4"
}

UPDATE: works even without useDefaultIdType

"uuid": {
   "type": "string",
   "id": true,
   "defaultFn": "uuidv4"
}

[fasenderos]

Although the model relations now seem to work fine, most of the methods don't.

For ex Customer.create() returns an object without the ID prop but with the auto incremented id in the UUID prop, like this:

"uuid": 100, -> The auto incremented ID
"name": "John Doe"

While in the db the entry is:

"id": 100
"uuid": "281d25ba-1685-463f-812a-0f1c2b77bbd9",
"name": "John Doe"

[agnes512]

@fasenderos I think LB3 takes the id property as the source key by default. That's why when set the uuid property to id: true the relation works. I am not sure if lb3 can customize the source key. Can you try to set the primary key of relations as:

Customer

... customer mode def
  "properties": {
    "id": {
      "id": true,   // model primary key is still id 
      "generated": true,
      "type": "number"
    },
    "uuid": {
      "type": "string",
      "defaultFn": "uuidv4"
    },
   }..
.....
  "relations": {
    "addresses": {
      "model": "address",
      "type": "hasMany",
      // edit: should be "customerUuid"
      "foreignKey": "customerId",
      "primaryKey": "uuid" . // customized primary key
    }
  },

Address

... address mode def
  "relations": {
    "addresses": {
      "model": "customer",
      "type": "belongsTo",
      // edit: should be "customerUuid"
      "foreignKey": "customerId",
      "primaryKey": "uuid" .   // customized primary key
    }
  },

I am also curious about the result of Customer.create() . I have no clue why it returns the wrong uuid and ignores id. Do you mind posting your Customer model definition here? thanks.