CODEWITHSUNDEEP
jsonnode.jsstronglooploopbackjs
Nishant
Nishant

Reputation: 3694

Ensure unique field value in loopback model

How to ensure uniqueness of a particular field in loopback model. Like below is the model Post, I have a field genericId in it, I want it to be unique in the database, and loopback to through an error, on duplicate key insertion.

{
  "name": "Post",
  "plural": "Post",
  "base": "PersistedModel",
  "properties": {
    "genericId": {
      "type": "string",
      "required":True 
    },
    "moderatedAt": {
      "type": "date"
    }
  },
  "validations": [],
  "acls": [],
  "methods": []
}

I have tried searching there documentation, and other examples but no success. One solution which I can think of is, to create a remoteHook for the create function, and validate this field before inserting, but looking for some other way.

Upvotes: 21

Views: 17231

Answers (3)

Mathias Arens
Mathias Arens

Reputation: 317

The Lookback v4 solution looks like this:

@model()
export class Client extends Entity {

  @property({
    type: 'string',
    required: true,
    index: {
      unique: true,
    },
  })
  name: string;

}

Then you must update your schema:

npm run migrate

or recreate it:

npm run migrate -- --rebuild

Upvotes: 10

IvanZh
IvanZh

Reputation: 2290

Set validation rule in your common/models/post.js

Post.validatesUniquenessOf('genericId');

Upvotes: 28

Pandaiolo
Pandaiolo

Reputation: 11568

Not sure if it is the better way to achieve uniqueness, but you can find here the docs about indexing your model.

Just add a unique index on the field you want, and voila !

For your model, that would be :

{
  ...
    "genericId": {
      "type": "string",
      "required": True,
      "index": {"unique": true} 
    },
 ...
}

However, if the genericId field is the actual Id of the model, I suggest you declare it as such, so you can use findById method, and also avoid creation of a duplicate id field, which will happen if you don't declare any in your model.

{
  ...
    "genericId": {
      "type": "string", 
      "id": true,       // Ensure uniqueness and avoid another model id field
      "generated": true // Add this if you want Loopback to manage id content for you
    },
 ...
}

Upvotes: 30

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