Version: 0.16.x

GraphQL Migrations

Graphback uses graphql-migrations to automatically create and update tables from a GraphQL schema. The library compares your database schema to your GraphQL schema and executes the required changes to keep the database structure synchronised with the GraphQL schema. The package is built on top of Knex.js, a flexible SQL query builder.

Compatibility

  • PostgreSQL (create and update database)
  • SQLite (create database only)

Installation

You can install graphql-migrations on your existing project using the following commmands:

With npm:

npm i graphql-migrations knex

or with yarn:

yarn add graphql-migrations knex

Usage

GraphQL Migrations operates on business models defined in your schema: These are GraphQL types decorated with a @model annotation. The package expose an API which you can programmatically set up in your source code and have it perform the migrations.

The package exposes a migrateDB method which creates and updates your tables and columns to match your GraphQL schema. All the database operations are wrapped in a single transaction, so your database will be fully rolled back to its initial state if an error occurs. The method takes three arguments as described in migrations options section.

import { migrateDB } from 'graphql-migrations';
const schemaText = ```
"""
@model
"""
type Note {
id: ID!
title: String!
}
```;
const dbConfig = {
// Knex.js based configuration
};
migrateDB(dbConfig, schemaText, {
// Additional options
}).then((ops) => {
console.log(ops);
});
...

Assuming the above code is ran against a PostgreSQL database, the following relations will be created:

\d
List of relations
Schema | Name | Type | Owner
--------+-------------+----------+------------
public | note | table | postgresql
public | note_id_seq | sequence | postgresql

And the note table:

\d note
Table "public.note"
Column | Type | Modifiers
--------+------------------------+---------------------------------------------------
title | character varying(255) | not null
id | integer | not null default nextval('note_id_seq'::regclass)
Indexes:
"note_pkey" PRIMARY KEY, btree (id)

Advanced usage

For more advanced usage, visit the below pages: