ORM

Add ORM capabilities to RxDB collections and documents with custom static methods, instance methods, and attachment methods for structured data access.

Object-Data-Relational-Mapping

Like mongoose, RxDB has ORM capabilities which can be used to add specific behavior to documents and collections.

statics

Statics are defined collection-wide and can be called on the collection.

Add statics to a collection

To add static functions, pass a statics object when you create your collection. The object contains functions, mapped to their function names.

javascript

const heroes = await myDatabase.addCollections({
  heroes: {
    schema: mySchema,
    statics: {
      scream: function(){
          return 'AAAH!!';
      }
    }
  }
});

console.log(heroes.scream());
// 'AAAH!!'

You can also use the this keyword which resolves to the collection:

javascript

const heroes = await myDatabase.addCollections({
  heroes: {
    schema: mySchema,
    statics: {
      whoAmI: function(){
          return this.name;
      }
    }
  }
});
console.log(heroes.whoAmI());
// 'heroes'

Instance Methods

Instance methods are defined collection-wide. They can be called on the RxDocuments of the collection.

Add instance methods to a collection

javascript

const heroes = await myDatabase.addCollections({
  heroes: {
    schema: mySchema,
    methods: {
      scream: function(){
        return 'AAAH!!';
      }
    }
  }
});
const doc = await heroes.findOne().exec();
console.log(doc.scream());
// 'AAAH!!'

Here you can also use the this keyword:

javascript

const heroes = await myDatabase.addCollections({
  heroes: {
    schema: mySchema,
    methods: {
      whoAmI: function(){
          return 'I am ' + this.name + '!!';
      }
    }
  }
});
await heroes.insert({
  name: 'Skeletor'
});
const doc = await heroes.findOne().exec();
console.log(doc.whoAmI());
// 'I am Skeletor!!'

attachment-methods

Attachment methods are defined collection-wide. They can be called on the RxAttachments of the RxDocuments of the collection.

javascript

const heroes = await myDatabase.addCollections({
  heroes: {
    schema: mySchema,
    attachments: {
      scream: function(){
          return 'AAAH!!';
      }
    }
  }
});
const doc = await heroes.findOne().exec();
const attachment = await doc.putAttachment({
    id: 'cat.txt',
    data: 'meow I am a kitty',
    type: 'text/plain'
});
console.log(attachment.scream());
// 'AAAH!!'