Section: Protection of Information Assets
Explanation:
In a relational database with referential integrity, the use of foreign keys would prevent events such as primary key changes and record deletions, resulting in orphaned relations within the database. It should not be possible to delete a row from a customer table when the customer number (primary key) of that row is stored with live orders on the orders table (the foreign key to the customer table). A primary key works in one table, so it is not able to provide/ensure referential integrity by itself. Secondary keys that are not foreign keys are not subject to referential integrity checks. Public key is related to encryption and not linked in any way to referential integrity.

Explanation
The best method for maintaining the security of corporate applications pushed to employee-owned mobile devices is implementing mobile device management (MDM). MDM is a software solution that allows an organization to remotely manage, configure, and secure the mobile devices that access its network and data.
MDM can help protect corporate applications on employee-owned devices by:
Enforcing security policies and settings, such as encryption, password, firewall, antivirus, and VPN.
Controlling the installation, update, and removal of corporate applications and data.
Separating corporate and personal data and applications on the device using containers or profiles.
Monitoring and auditing the device's compliance status, activity, and location.
Performing remote actions, such as lock, wipe, backup, or restore, in case of loss, theft, or compromise.
MDM can provide a comprehensive and centralized approach to maintain the security of corporate applications on employee-owned devices, regardless of the device type, platform, or ownership. MDM can also help the organization comply with regulatory and industry standards for data protection and privacy.
Enabling remote data destruction capabilities is a useful feature for maintaining the security of corporate applications on employee-owned devices, but it is not the best method by itself. Remote data destruction allows the organization to erase the corporate data and applications from the device in case of loss, theft, or compromise. However, this feature does not prevent unauthorized access or misuse of the corporate data and applications before they are destroyed. Remote data destruction is usually part of an MDM solution.
Disabling unnecessary network connectivity options is a good practice for maintaining the security of corporate applications on employee-owned devices, but it is not the best method by itself. Network connectivity options, such as Wi-Fi, Bluetooth, NFC, or USB, can expose the device to potential attacks or data leakage. Disabling these options when they are not needed can reduce the attack surface and improve battery life. However, this practice does not address other security risks or requirements for the corporate applications on the device. Disabling network connectivity options can also be part of an MDM solution.
Requiring security awareness training for mobile users is an important measure for maintaining the security of corporate applications on employee-owned devices, but it is not the best method by itself. Security awareness training can educate the users about the potential threats and best practices for using their devices securely. It can also help foster a culture of security and responsibility among the users. However, security awareness training cannot guarantee that the users will follow the security policies and guidelines consistently and correctly. Security awareness training should be complemented by technical controls, such as MDM.
References:
Protecting Corporate Data on Mobile Devices for All Companies1
Mobile Device Security: Corporate-Owned Personally-Enabled (COPE)23