To create a form that will create a record for a custom object, the developer can use a Dynamic Form, which is a Lightning App Builder component that allows you to customize the fields and sections of a record page layout1. A Dynamic Form can also use visibility rules to display different fields based on the user's profile, role, or other criteria2. To add the functionality to the Account record page, the developer can use a Dynamic Action, which is a way to configure actions on a record page without code3. A Dynamic Action can also use visibility rules to show or hide actions based on the user's profile, role, or other criteria4. To restrict the functionality to a small group of users, the developer can create a Custom Permission, which is a way to grant access to custom processes or apps5. A Custom Permission can be assigned to a permission set or a profile, and then assigned to the users who need it. References:
* Dynamic Forms | Salesforce Trailhead
* Visibility Rules for Dynamic Forms | Salesforce Help
* Dynamic Actions | Salesforce Trailhead
* Visibility Rules for Dynamic Actions | Salesforce Help
* Custom Permissions | Salesforce Trailhead
* [Assign Custom Permissions | Salesforce Help]
In Apex, if a SOQL query returns more than one row and the result is assigned to a single sObject variable, an exception will be thrown. This is because a single sObject variable can only hold one record. In this case, since myAccount is declared as a single Account object, it cannot hold more than one record. If the SOQL query returns more than one Account, an unhandled exception occurs, and the code terminates. References:
The behavior can be understood from the Apex Developer Guide under the section of SOQL Queries