Quick answers to key questions

• Workflow and Process Builder. Workflow rules are simple, work on one object and support only four action types. Process Builder supports several criteria and more actions, such as creating records and calling Apex or flows. Both are retired in favour of Flow.
• What is a Lightning component bundle? A bundle is the folder of files that make up one component. An Aura bundle can contain markup, controller, helper, style, design, documentation and renderer files. An LWC bundle contains the HTML, JavaScript, CSS and the meta XML file.
• Helper and controller in Aura. The controller handles events from the component and calls the helper. The helper holds reusable logic that several controller functions share, which keeps the controller small.
• Design resource in LWC. In Aura, the design file defines properties that admins can set in Lightning App Builder. In LWC the same is done in the targetConfigs section of the .js-meta.xml file.
• Master-detail and lookup, security wise. In a master-detail relationship, the child record has no owner and takes its sharing and access from the master record. In a lookup, the child has its own owner and its own sharing, independent of the parent.
• Relationship between Account and Contact. A one-to-many lookup relationship.
• Mixed DML exception. It happens when one transaction changes a setup object (such as User, Profile or Permission Set Assignment) and a non-setup object (such as Account) together. To avoid it, perform one of the two operations in a separate transaction, for example with a future method or a queueable job. In test classes, use System.runAs().
• Trigger context variables. Trigger.new, Trigger.old, Trigger.newMap, Trigger.oldMap, Trigger.isInsert, isUpdate, isDelete, isUndelete, isBefore, isAfter and Trigger.size.
• Batch class methods and sizes. start returns the records to process, execute processes each chunk, and finish runs once at the end. The default batch size is 200 and the maximum is 2,000.
• How do you provide security for a record? With OWD for the baseline, then the role hierarchy, sharing rules, manual sharing, and teams to open up access.
• Role and profile. A profile controls what a user can do (object, field and system permissions). A role controls which records the user can see through the hierarchy.
• Can one user have multiple profiles? No. A user has exactly one profile, and extra permissions are given with permission sets.
• Types of collections in Apex. A List is ordered and allows duplicates. A Set holds unique values with no guaranteed order. A Map stores key and value pairs with unique keys.

Order of execution (simplified)

1. The record is loaded and system validation runs for the request.
2. Before-save record-triggered flows run.
3. Before triggers run.
4. System validation and custom validation rules run.
5. Duplicate rules run.
6. The record is saved to the database but not committed.
7. After triggers run.
8. Assignment, auto-response and escalation rules run, and workflow rules still in use are evaluated.
9. After-save record-triggered flows run.
10. Roll-up summary fields and sharing rules are recalculated.
11. The transaction is committed, and then post-commit actions such as emails run.

Salesforce documents the full order in the Apex Developer Guide, and the exact order can change slightly between releases.