Quick answers to key questions

Short answers to the technical questions above. For the experience questions, answer from your own project.

• Relationships in Salesforce. Lookup, master-detail, many-to-many through a junction object, self relationship, hierarchical (User only), and external and indirect lookups. When you give a scenario, mention why you chose one type, for example master-detail when the child cannot exist without the parent and you need roll-up summaries.
• Collections in Apex. List (ordered, allows duplicates), Set (unique values) and Map (key and value pairs with unique keys).
• Sharing rules and settings. OWD sets the baseline access. The role hierarchy gives managers access to their team records. Sharing rules open access to groups of users based on ownership or record criteria. Manual sharing and teams cover individual cases.
• Deployment process. Develop in a sandbox, test in a UAT sandbox, and deploy to production with change sets or with Salesforce CLI and a source-control pipeline. Run a validation first, make sure the tests pass and coverage is at least 75%, and deploy in a planned release window.
• Eclipse. The Force.com IDE for Eclipse is retired. Developers now use Visual Studio Code with the Salesforce Extension Pack.
• Data Loader. A client tool for bulk insert, update, upsert, delete and export of records. It can run through the Bulk API for large volumes.

Expose an Apex class as a REST web service

@RestResource(urlMapping='/accounts/*')
global with sharing class AccountRestService {
    @HttpGet
    global static Account getAccount() {
        RestRequest req = RestContext.request;
        String accountId = req.requestURI.substring(req.requestURI.lastIndexOf('/') + 1);
        return [SELECT Id, Name, Phone, Website FROM Account WHERE Id = :accountId];
    }
}

The class must be global, and each method uses an annotation such as @HttpGet, @HttpPost, @HttpPatch or @HttpDelete. An external system calls it at /services/apexrest/accounts/{id} after authenticating with a Connected App and OAuth.

Integration scenarios

• A third-party system needs Account details. Give the system an integration user and a Connected App for OAuth. It can then call the standard REST API (for example a query on Account) or your own Apex REST service. Give the user only the permissions it needs.
• Syncing 100k to 500k records to an external system. Do not use a real-time callout per record. Use a bulk approach, such as Bulk API 2.0, batch Apex with callouts in small scopes, Change Data Capture or Platform Events with a middleware tool, and send the data in chunks.
• Handling integration errors and the other system being down. Catch errors and log the failed request in a custom object with the payload and error message. Retry later with queueable or scheduled Apex, set timeouts, and alert the support team through email or a platform event. Use Named Credentials so endpoints and credentials are not hard-coded.