@nexys/fetchr

Fetch-R

Typescript ORM to connect to MySQL database

experimental support for PostgreSQL

Typescript port of Scala version

Get started with the package

Install

yarn add @nexys/fetchr

Use

import FetchR from "@nexys/fetchr";
import { Database } from "@nexys/fetchr/dist/database/type";
import { Entity } from "@nexys/fetchr/dist/type";

const model: Entity[] = [
  {
    name: "User",
    uuid: false,
    fields: [
      { name: "firstName", type: "String", optional: false },
      { name: "lastName", type: "String", optional: false },
      { name: "email", type: "String", optional: false },
    ],
  },
];

const dbConfig: Database = {
  username: "",
  host: "",
  password: "",
  database: "",
  port: 3306,
};

const fetchr = new FetchR(dbConfig, model);

fetchr.mutate({
  User: {
    insert: {
      data: { firstName: "john", lastName: "doe", email: "[e-mail]" },
    },
  },
});

// get all users
fetchr.query({ User: {} });

// get all users' emails whose names are "john"
fetchr.query({
  User: { projection: { firstName: true }, filters: { firstName: "John" } },
});

Querying

There are 2 endpoints for querying: /data and /mutate. As their names suggests, the first one retrieves data and the second alters them. This is based on the same philosophy that was adopted by graphql.

Data

This is the query endpoint: /query (for legacy reason the endpoint /data is also available)

The querying language is very easy is straightforward and follows the structure defined here.

Note that the endpoint always returns an object with the different entities queries as keys and the result in the form of an array as values.

Query Example

• get a list of user from the entity User

{User: {}}

• get a list of user belonging to a particulart workspace

{User: {workspace:{id: workspaceId}}}

Mutate

Available through /mutate. The following actions are available

• insert
• update
• delete

Model and Databases

The service supports multi models/databases

Models

• Models can be set using /model/set
• The strcuture is the one descrbied in /service/type
• Models are stored in /assets/models.json

Databases

• Models can be set using /database/set
• The strcuture is the one descrbied in /service/database/type
• Databases are stored in /assets/databases.json

When a query requiring a particular database is called, it will look for an associated connection pool. If none is found, it will create a new one based on the database record (if not found, an error is thrown) and store it in a Map object.

Migrations

The migration engines is largely inspired from flyway. An array of migrations can be passed; each having a unique combination of index and version (e.g. 2.1, 2.2 etc). Migrations are stored in a separate table with their checksum values.

GraphQL

GraphQL support is available. See https://github.com/nexys-system/server-boilerplate/blob/master/README.md#graphql-query-examples-tested-in-postman for more information