The research emphasizes the importance of applying theoretical knowledge in legal practice, especially concerning the notion under General Data Protection Regulation (GDPR) Article 9 when legislator, according to paragraph 2, has allowed the use of artificial intelligence based on exceptions provided in «a» and «b» from the prohibition rule under paragraph 1 of the mentioned provision. Due to that, research reveals legal relations concerning unique identification practices in the workplace. Two kinds of legal relations are targeted as examples. The first one involves the time management of employees at the workplace, where the application of the principle of proportionality exemplifies that unique identification can only be practiced if there is a strict necessity. The second one discussed in terms of regulations for implementing devices that use biometric authentication for the access control to premises in workplaces under consent given by the employee.The research confirms that unique identification in the workplace is acceptable under Article 9 (2, a & b) of the GDPR, but interference with the fundamental right of an employee to the personal data protection in a workstation for unique identification must be legitimate and proportionate to the terms to derogate from the GDPR Article 9 (1). The research suggests installing the advancement of operative interfaces and experienced technology with non-biometric intelligent systems that can deliver ample time tracking in the workplace.