Getting Started

General information

We are using Firebase as backend provider and its database service Firestore to store our data.

Preliminary research

addressing issue #23

• For building an app's backend, 3 main components need to be considered:
  • Middleware: connection from front-end to back-end
  • Database: indicates UI for data penetration and memory persistence
  • Server: offers resource-sharing content, web services, databases, file storage (Cloud?)
• as we only require a backend for storing our database in the cloud (and thus making it accessible simultaneously from several devices in the future), setting up our own infrastructure would be a complete overkill for the first prototype
• therefore, we decided to rely on a third party provider for our backend and compared some popular ones to choose the most suitable one for our application:

	Firebase	Back4App	AWS (Amplify)
Flutter + React	yes	yes	yes
Cross-platform	yes	yes	yes
Conditions	1 GB, 20k writes/day, 50k reads/day	25k Requests/month, 250 MB Data Storage, 1 GB Transfer, 1 GB Storage	after 1 year: 0,01 $/min per creation, 0,023$ per GB storage
Database type	noSQL	noSQL	relational/ SQL

All services have comparable features and fulfill our requirements. Firebase offers the most storage, database reads/writes on its free plan, amongst all compared providers. Additionally, it provides a seamless integration with our frontend framework Flutter, as both are products from Google, and was therefore picked as the provider to work with.

Account information

The database is stored under a Google Account of our project using the mail address madlabhandball@gmail.com. It is linked with Annikas phone number (sometimes required for 2-Factor-Authentication, can be changed in the future) and the password is known to all team members. One can login to the firebase dashboard here: https://console.firebase.google.com/.

Set up

Installing Firebase CLI

https://firebase.google.com/docs/cli#setup_update_cli You can put the binary .exe file in the root of your projects directory.

Adressing issue #36

Set Up Cloud Firestore DB (only once for entire project)

followed https://firebase.google.com/docs/firestore/quickstart?authuser=1:
The project is called Handball Performance Tracker. We used "Testmodus" as Security mode and europe-central as storage place for the Firestore Database.

Add Firestore project to our flutter project (only once for entire project)

followed https://firebase.google.com/docs/flutter/setup?authuser=1&platform=ios:
Used Commands:

curl -sL https://firebase.tools | bash
firebase login (with group gmail account)
dart pub global activate flutterfire_cli
flutterfire configure --project=handball-performance-tracker

Use Firebase in the Flutter project (individually after cloning the project)

To use firebase in our Flutter project you need to install the plugin with flutter pub add cloud_firestore or just push pub get in your IDE.

Gui Tool

https://refiapp.io allows to edit firestore in a table view. This makes life much easier than using the editor in the browser.

Database layout

Adressing issue #38

Selecting a project to work

Disclaimer: this does not seem to work 100% yet

Run in your terminal: firebase projects:list

Firestore: General information

• data stored in documents, that are organized in collections
• documents:
  • contain a set of key ("field")-value pairs
  • lightweight, json-like records
  • contain strings/lists/maps
  • max 1 MB
  • can contain subcollections
• collections:
  • containers for documents
  • can only contain documents
  • no need to "create" or "delete" collections
  • after creating the first document in a collection, it exists
  • after deleting all of the documents in a collection, it no longer exists
• references:
  • can be retrieved for every document/collection
  • can be created no matter if the document exists, does not perform any network operations
• indexing
  • indexes are used to quickly look up the locations of queried items in the database
  • used for all queries in firestore
  • single-field indexes:
    • store a sorted mapping of all the documents in a collection that contain a specific field
    • automatically maintained by firestore forr each field in a document and each subfield in a map
  • composite indexes:
    • store sorted mapping of all documents in a collection
    • used to support queries that are not already supported by single-field-indexes
    • can be created manually during app programming
• optimized for storing large collections of small documents
• best practices:
  • avoid nesting data: when data at a location in your database is fetched,all child nodes are also retrieved automatically; normalize data instead, e.g. separate information as much as possible
  • for two-way relationships, storing data redundant is the most elegant way
  • pay attention that if a value is stored redundant, it needs to be deleted from multiple locations to finally delete it