Cloud Database Basics

Introduction

Skygear allows users to store records to Skygear's PostgreSQL cloud database. You can even define your own type of Record and add customized fields to suit you needs.

Before you proceed, please make sure:

• You have your Skygear container configured. Simply follows the guide at Setup Skygear if you haven't.

• You have signed up as a User and logged in, as you have to be authenticated to perform any database operations. For guide on sign up and log in, go to User Authentication Basics.

To visualize your database with graphical presentation, you can go to the Database section in Skygear Portal and open our web data browser.

Record

• Record must have a type.
• Each Record object is like a dictionary with keys and values; keys will be mapped to database column names, and values will be stored appropriately based on the data type. section for more information.
• Record will be owned by the currently logged in user.
• Each Record object has its unique id (combination of record type and uuid used in the database as _id).
• Record has reserved keys that cannot be used, such as id and _id. Please refer to Reserved Columns section for more.
• Please note Skygear database uses PostgreSQL. You are given the direct access of the database and therefore can open the database of your app using a PostgreSQL client. Details can be found on the Skygear Portal.

You can design different Record types to model your app. Just like defining tables in SQL.

const Note = skygear.Record.extend('note');
  //You can use 'Note' to reference the 'note' record type.

const note = new Note({ 'content': 'Hello World' });
  //This creates a new record value 'Hello World' stored under a column called 'content' in the 'note' record type.

const Blog = skygear.Record.extend('blog');
  //You can also define a different record type (e.g. a blog).

Database

You will be provided with a private and a public database.

• Everything in the private database is truly private, regardless of what access control entity you set to the record. In other words, each user has his own private database, and only himself has access to it.
• Record saved at public database is by default public. Even without logging in, records in the public database can be queried (but not updated). To control the access, you may set different access control to the record.
• The database objects can be accessed with skygear.publicDB and skygear.privateDB.

Data type

Skygear supports most built-in JavaScript types:

• String
• Number
• Boolean
• Array
• Object
• Date

There are also four other types provided by Skygear JS SDK:

• Reference (relational records)
• Asset (files)
• Sequence
• Location

You will learn how to works with these data type in Relational Records, File storage and Location, Auto-increment sequence fields.

Reserved columns

There are quite a few reserved columns for storing records into the database. Those contain the metadata of a record. The column names are written as snake_case while the JS object attributes are mapped with camelCase. Please notice this one-to-one mapping. When you want to query on reserved columns, make sure to use snake_case; when you get records back as a JS object, make sure to access attributes with camelCase. When creating and saving records, please avoid using attribute that is the same as any one of the camelCase attribute names listed below.

Learn how to work with the reserved columns in More About Queries.