Understand multi-tenant concepts and design frameworks, such as MVC architecture and Lightning Component Framework.

04 Oct 2022

These are technical notes I compiled while studying using Focus on Force, a company that provides Salesforce training and certification prep services.

After studying this topic, you should be able to:

Describe the features and how system resources are accessed and applications developed in a multi-tenant environment.
Identify the considerations related to system updates in a multi-environment and use of shared resources.
Identify the different components of the MVC architecture and what they represent.
Describe the main features of the Lightning Component Framework.
Describe the features available for building applications using declarative and programmatic tools.

Table of Contents

MVC Architecture
Lightning Component Framework
App manager
Lightning App Builder
Declarative Tools
Programmatic Tools
Lightning Platform APIs

Introduction - Multi-Tenant Architecture

Salesforce has a multi-tenant architecture with unique features:
- Cloud computing: Platform as a Service (PaaS)
- Shared system resources: CPU usage, queries, and records returned are limited per customer
  - If governor limits are exceeded, exceptions are thrown - these can be designed for
- Automatic system updates: upgrades roll out 3x per year in Spring, Summer, and Winter
- Metadata-driven kernel: architecture separates runtime database engine (kernel), tenant data, and metadata

MVC Architecture

MVC is an architectural pattern that separates data layer from business logic/how data is presented in the user interface
- Model: represents structure of the data through sObjects, fields, Apex classes
  - Standard objects, custom objects, object fields, object relationships, apex classes (data)
- View: represents the presentation layer which consists of pages and components
  - Standard pages, visualforce pages, visualforce components, custom tabs, page layouts
- Controller: represents the business logic. Custom controllers/controller extensions are Apex classes
  - Standard controllers, custom controllers (apex), extensions (apex), declarative rules and tools (apex triggers, validation rules, processes, etc)

Lightning Component Framework

Lightning Component Framework is a UI framework for building single-page web apps
- Uses stateful JavaScript on Client side, stateless Apex on Server side - client only calls the server when necessary, so apps are more responsive and efficient
- Lightning components can be built using Aura Components or Lightning Web Components model, which can coexist
- Event-Driven Architecture: components are capable of listening to events and responding
Aura/LWC web components follow MVCC (Model-View-Controller-Controller):
- Model: database (sObjects, fields, Apex classes)
- View: lightning component
- Controller (client-side): Javascript - client-side operations, intermediary between server and UI
- Controller (server-side): Apex - performs database operations, JavaScript calls Apex methods
Lightning Component framework - set of prebuilt self-contained and reusable components
- Aura components:
  - Only requires a markup file, but can also include controller, helper, CSS styles, design, documentation, renderer, and/or SVG files
- Lightning Web component:
  - Follows web standards, typically contain HTML, JavaScript, CSS, and/or XML files

App manager

Apps: groups of tabs that work together as a unit, created from the App Manager in setup
- Item at the top of list in Navigation Bar become the app’s landing page
- Lightning apps contain standard and custom tabs, Visualforce tabs, Lightning component tabs, Canvas apps, web tabs, Lightning Page tabs, and utilities like Sales Dialer.
- Utility Items can be added to the utility bar
- Navigation style (standard or console) and navigation rules for the Console navigation style (open as Workspace tabs/subtabs)
- Form factors (mobile, desktop, both)
- Only profiles assigned to the app will be able to access it

Lightning App Builder

Lightning App Builder is a declarative tool that can be used to create and configure custom pages for Lightning Experience and Salesforce mobile app
- Lightning App Builder allows building single-page apps, dashboard-style apps, “point” apps that solve a particular task, custom record pages, custom Home pages, custom email application panes
- Standard lightning components include Accordion, Chatter, Record Detail, Related Record
- Custom lightning components can be added to a lightning page
- Dynamic lightning pages make it possible to configure when a component appears on a Lightning page by adding filter conditions and logic in Lightning App Builder

Declarative Tools

Declarative automation tools can be used to implement simple and complex business processes:
- Process Builder: useful when complexity of a business process consists of multiple if/then statements
  - Can be used to: create new records, update any related record, invoke Apex code, create a Chatter post, send an email alert, submit a record for approval, launch a flow or other process, send a custom notification
- Flow Builder: automate a guided visual experience, start a business process from a user interaction, process, schedule, platform event, or record change.
  - Can be used to: create new records, delete records, launch another flow, update any record, send an email alert, send a custom notification, invoke Apex code, submit a record for approval, create a Chatter post, send an outbound message
- Approval Process: can be used to submit a record for approval when a user clicks a button/link or when a flow/process submits a record for approval
  - Can be used to: create new tasks, send an email alert, update the original record or its parent, send an outbound message
- Workflow Rule: can be used to implement a business process that consists of a single if/then statement
  - Can be used to: create new tasks, send an email alert, update the original record or its parent, send an outbound message
Declarative sharing & security tools can be used to expose different data sets to different sets of users
- Profiles & Permission Sets: can be used to specify objects and fields that users can access as well as user permissions
- Record Access controlled by specifying org-wide default sharing settings
Declarative business logic & validation tools
- Roll-up summary fields: can be used to automatically calculate the value of a field on a parent record based on child records
- Validation rules: can be used to verify that the data entered by a user meets certain standards before the record is saved
Declarative user interface tools
- App Manager: container for a set of items like object tabs/utility items
- Lightning App Builder
- Quick Actions: Object-specific and global quick actions let users invoke custom functionality when using the UI
Declarative data management tools
- Data Import Wizard: supports imports of up to 50,000 records
- Dataloader: supports insert, update, upsert, delete, or export of up to 5,000,000 records.
Declarative analytics tools
- Report Builder, Dashboards, Report and Dashboard Folders

Programmatic Tools

Programmatic features are used when a required functionality cannot be achieved using declarative tools
Apex: used for complex business logic for apps.
- Invocable Apex method: can be created and invoked as an Apex action in a process or flow
- Apex triggers: can be created to execute custom business logic before/after a record is created/updated/deleted/merged/upserted/undeleted
- Used for integration with external systems
Visualforce: framework that can be used to build custom user interfaces, mainly for Salesforce Classic
- Uses a tag-based markup language consisting of Visualforce tags, HTML, JavaScript, or other Web-enabled code embedded within a apex:page tag.
- Can be used to override standard buttons, define custom tabs, create dashboard components, etc
Apex class below contains invocable method callable from Flow Builder or Process Builder

// An Apex class is allowed to have one (1) invocable method only
public class CustomBusinessLogic {
    @InvocableMethod
    public static void processAccounts() {
        // perform logic or process which a declarative tool is not capable of achieving
        ...
    }
}

Call the function above in Process Builder by specifying an “Action Type” of “Apex”
Lightning Aura Components: the original aura components model includes aura components that are self-contained, reusable units of an app that represent sections of the UI
Lightning Web Components: uses core Web Components standards. HTML and modern JavaScript can be used to build LWCs.
Aura and Lightning web components can be used in custom tabs, Lightning pages, Experience Builder, Flows, Visualforce pages, etc

Lightning Platform APIs

Wide range of useful APIs for various scenarios:
- REST API: programmatically access or process Salesforce data from an external application
- SOAP API: access, search, and perform DML operations on records from an external application
- Chatter REST API: show Chatter related data such as feed, users, or groups
- User Interface API: build user interfaces that surface records, list views, quick actions, favorites, and other components
- Analytics REST API: grants programmatic access to Salesforce Analytics data such as datasets, lenses, and dashboards
- Bulk API: lets developers and admins perform CRUD actions on large datasets (hundreds of thousands to millions of records) asynchronously in batches
- Metadata API: allows developers to programmatically retrieve, deploy, create, update, or delete customizations or metadata in an org
- Streaming API: used in receiving notifications based on record-change events or custom events in Salesforce
- Apex REST API: allows Apex classes to be exposed and invoked by external applications as REST web services
- Apex SOAP API: allows Apex classes to be exposed and invoked by external applications as SOAP web services
- Tooling API: provides ability to write SOQL queries for many metadata types in an org