Repository is a communication layer between models and external storage. Basically, there is no limitation what can be treated as an external storage. It may be anything: relational databases, NoSQL databases, flat files databases, cloud storage, microservices, etc.

By default, Dominion framework package doesn’t include any repository, because type of external storage specifically depends on projects architecture, so, there is no reason to include something you will never use.

To use repository in your component you will need to install npm package with a repository you need. For example, for MySQL:

npm install @dominion-framework/repository-mysql

Then, you need to create repository declaration in your component’s folder and link it with a model. The most basic repository will contain only Repository.create() function. For example a file repository.js may look like:

const Repositories = require('@dominion-framework/repository-mysql');

module.exports = Repositories.create('books_table', { });

In a model declaration use repository: property to link created repository to a model:

const Property = require("@dominion-framework/dominion/core/property");

const BooksRepository = require("./repository");

module.exports = {

    name: "Books",

    repository: BooksRepository, 

    properties: {

Repository prototype

Default repositories are coming with three basic functions for manipulating a model - find(), save() and remove(). If you are creating your own repository, take them as an interface you need to implement.

.find( [criteriasObject], [limit], [offset], [order], [totalCountOnly=false] )

Returns an array with model’s data that matches criteriaObject. It is used in .get() and .find() methods of default models factories prototype. Basically it executes SELECT query, if we are talking about SQL databases. If totalCountOnly set to true, method should return only a number of records matching criteriasObject, ignoring limit and offset parameters.

.save( [modelInstance] )

Creates or updates model data. In case of creation, optionally it can return primary key of a new record, which then will be set in Model instance. It is used in .save() method of default models instance prototype. Take it as INSERT or UPDATE query, in case of SQL.

.remove( [modelInstance] )

Removes model data from external storage. It is used in .remove() method of default models instance prototype. Obviously, it is DELETE query in case of SQL type of repositories.

Extending Repository

If you need to add missing features to the repository or overwrite default methods, you can define custom methods when creating repository. In example below, default repository prototype is extended with method findByTitle().

const Repositories = require('@dominion-framework/repository-mysql');

module.exports = Repositories.create('books_table', {

    findByTitle(title, offset, limit) {
        const query = `SELECT * FROM ${this.__table__} 
                       WHERE title LIKE ?
                       LIMIT ?, ?`;
        return this.db.execute(query, [`%${title}%`, offset, limit])
            .then(([rows, columns]) => rows);


Note, custom methods in Repositories should return raw data. Any data post-processing should be performed in models or factories.