In a database, you have entities (which have attributes), and relationships between those entities. Managing them is key to preventing chaos from engulfing your database, which is where the concept of keys comes in. These unique identifiers enable you to pick specific rows in an entity set, as well as define their relationships to rows in other entity sets, allowing your database to handle complex computations.


Let’s explore keys in DBMS (database management systems) in more detail, before digging into everything you need to know about the most important keys – primary keys.


Understanding Keys in DBMS


Keys in DBMS are attributes that you use to identify specific rows inside a table, in addition to finding the relation between two tables. For example, let’s say you have a table for students, with that table recording each student’s “ID Number,” “Name,” “Address,” and “Teacher” as attributes. If you want to identify a specific student in the table, you’ll need to use one of these attributes as a key that allows you to pull the student’s record from your database. In this case “ID Number” is likely the best choice because it’s a unique attribute that only applies to a single student.


Types of Keys in DBMS


Beyond the basics of serving as unique identifiers for rows in a database, keys in DBMS can take several forms:


  • Primary Keys – An attribute that is present in the table for all of the records it contains, with each instance of that attribute being unique to the record. The previously-mentioned “ID Number” for students is a great example, as no student can have the same number as another student.
  • Foreign Key – Foreign keys allow you to define and establish relationships between a pair of tables. If Table A needs to refer to the primary key in Table B, you’ll use a foreign key in Table A so you have values in that table to match those in Table B.
  • Unique Key – These are very similar to primary keys in that both contain unique identifiers for the records in a table. The only difference is that a unique key can contain a null value, whereas a primary key can’t.
  • Candidate Key – Though you may have picked a unique attribute to serve as your primary key, there may be other candidates within a table. Coming back to the student example, you may record the phone numbers and email addresses of your students, which can be as unique as the student ID assigned to the individual. These candidate keys are also unique identifiers, allowing them to be used in tandem with a primary key to identify a specific row in a table.
  • Composite Key – If you have attributes that wouldn’t be unique when taken alone, but can be combined to form a unique identifier for a record, you have a composite key.
  • Super Key – This term refers to the collection of attributes that uniquely identify a record, meaning it’s a combination of candidate keys. Just like an employer sifting through job candidates to find the perfect person, you’ll sift through your super key set to choose the ideal primary key amongst your candidate keys.

So, why are keys in DBMS so important?


Keys ensure you maintain data integrity across all of the tables that make up your database. Without them, the relationships between each table become messy hodgepodges, creating the potential for duplicate records and errors that deliver inaccurate reports from the database. Having unique identifiers (in the form of keys) allows you to be certain that any record you pull, and the relationships that apply to that record, are accurate and unrepeated.



Primary Key Essentials


As mentioned, any unique attribute in a table can serve as a primary key, though this doesn’t mean that every unique attribute is a great choice. The following characteristics help you to define the perfect primary key.


Uniqueness


If your primary key is repeatable across records, it can’t serve as a unique identifier for a single record. For example, our student table may have multiple people named “John,” so you can’t use the “Name” attribute to find a specific student. You need something unique to that student, such as the previously mentioned ID number.


Non-Null Values


Primary keys must always contain a value, else you risk losing records in a table because you have no way of calling upon them. This need for non-null values can be used to eliminate some candidates from primary key content. For instance, it’s feasible (though unlikely) that a student won’t have an email address, creating the potential for null values that mean the email address attribute can’t be a primary key.


Immutability


A primary key that can change over time is a key that can cause confusion. Immutability is the term used for any attribute that’s unchanging to the point where it’s an evergreen attribute that you can use to identify a specific record forever.


Minimal


Ideally, one table should have one attribute that serves as its primary key, which is where the term “minimal” comes in. It’s possible for a table to have a composite or super key set, though both create the possibility of confusion and data integrity issues.


The Importance of a Primary Key in DBMS


We can distill the reason why having a primary key in DBMS for each of your tables is important into the following reasons:


  • You can use a primary key to identify each unique record in a table, meaning no multi-result returns to your database searches.
  • Having a primary key means a record can’t be repeated in the table.
  • Primary keys make data retrieval more efficient because you can use a single attribute for searches rather than multiple.

Functions of Primary Keys


Primary keys in DBMS serve several functions, each of which is critical to your DBMS.


Data Identification


Imagine walking into a crowded room and shouting out a name. The odds are that several people (all of whom have the same name) will turn their heads to look at you. That’s basically what you’re doing if you try to pull records from a table without using a primary key.


A primary key in DBMS serves as a unique identifier that you can use to pull specific records. Coming back to the student example mentioned earlier, a “Student ID” is only applicable to a single student, making it a unique identifier you can use to find that student in your database.


Ensure Data Integrity


Primary keys protect data integrity in two ways.


First, they prevent duplicate records from building up inside a single table, ensuring you don’t get multiple instances of the same record. Second, they ensure referential integrity, which is the term used to describe what happens when one table in your database needs to refer to the records stored in another table.


For example, let’s say you have tables for “Students” and “Teachers” in your database. The primary keys assigned to your students and teachers allow you to pull individual records as needed from each table. But every “Teacher” has multiple “Students” in their class. So, your primary key from the “Students” table is used as a foreign key in the “Teachers” table, allowing you to denote the one-to-many relationship between a teacher and their class of students. That foreign key also ensures referential integrity because it contains the unique identifiers for students, which you can look up in your “Students” table.


Data Retrieval


If you need to pull a specific record from a table, you can’t rely on attributes that can repeat across several records in that table. Again, the “Name” example highlights the problem here, as several people could have the same name. You need a unique identifier for each record so you can retrieve a single record from a huge set without having to pore through hundreds (or even thousands) of records.


Best Practices for Primary Key Selection


Now that you understand how primary keys in DBMS work, here are some best practices for selecting the right primary key for your table:


  • Choose Appropriate Attributes as Candidates – If the attribute isn’t unique to each record, or it can contain a null value (as is the case with email addresses and phone numbers), it’s not a good candidate for a primary key.
  • Avoid Using Sensitive Information – Using personal or sensitive information as a primary key creates a security risk because anybody who cracks your database could use that information for other purposes. Make your primary keys unique, and only applicable, to your database, which allows you to encrypt any sensitive information stored in your tables.
  • Consider Surrogate Keys – Some tables don’t have natural attributes that you can use as primary keys. In these cases, you can create a primary key out of thin air and assign it to each record. The “Student ID” referenced earlier is a great example, as students entering a school don’t come with their own ID numbers. Those numbers are given to the student (or simply used in the database that collects their data), making them surrogate keys.
  • Ensure Primary Key Stability – Any attribute that can change isn’t suitable for use as a primary key because it causes stability issues. Names, email addresses, phone numbers, and even bank account details are all things that can change, making them unsuitable. Evergreen and unchanging is the way to go with primary keys.

Choose the Right Keys for Your Database


You need to understand the importance of a primary key in DBMS (or multiple primary keys when you have several tables) so you can define the relationships between tables and identify unique records inside your tables. Without primary keys, you’ll find it much harder to run reports because you won’t feel confident in the accuracy of the data returned. Each search may pull up duplicate or incorrect records because of a lack of unique identifiers.


Thankfully, many of the tables you create will have attributes that lend themselves well to primary key status. And even when that isn’t the case, you can use surrogate keys in DBMS to assign primary keys to your tables. Experiment with your databases, testing different potential primary keys to see what works best for you.

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OPIT Is Turning 2! What Have We Achieved in the Last 2 Years?
OPIT - Open Institute of Technology
OPIT - Open Institute of Technology
Aug 7, 2025 6 min read

The Open Institute of Technology (OPIT) is turning two! It has been both a long journey and a whirlwind trip to reach this milestone. But it is also the perfect time to stop and reflect on what we have achieved over the last two years, as well as assess our hopes for the future. Join us as we map our journey over the last two years and look forward to future plans.

July 2023: Launching OPIT

OPIT officially launched as an EU-accredited online higher education institution in July 2023, and offered two core programs: a BSc in Modern Computer Science and an MSc in Applied Data Science and AI. Its first class matriculated in September of that year.

The launch of OPIT was several years in the making. Founder Riccardo Ocleppo was planning OPIT ever since he launched his first company, Docsity, in 2010, an online platform for students to share access to educational resources. As part of working on that project, Ocleppo had the chance to talk to thousands of students and professors and discovered just how big a gap there is between what is taught in universities today and job market demands. Ocleppo felt that this gap was especially wide in the field of computer science, and OPIT was his concept to fill that gap.

The vision was to provide university-level teaching that was accessible around the world through digital learning technologies and that was also affordable. Ocleppo’s vision also involved international professors and building strong relationships with global companies to ensure a truly international and fit-for-purpose learning experience.

One of the most important parts of launching OPIT was the recruitment of the faculty of professors, which Ocleppo was personally involved in. The idea was to build a roster of expert teachers and professionals who were leaders in the field and urge them to unite the teaching fundamentals with real-world applications and experience. The process involved screening more than 5,000 CVs, interviewing over 200 candidates, and recruiting 25 professors to form the core of OPIT’s faculty.

September 2023: The Inaugural Cohort

When OPIT officially launched, its first cohort included 100 students from 38 different countries. Divided between the BSc and MSc courses, students were also allowed to participate in one of two different tracks. Some chose the standard track to accommodate their existing work commitments, while others chose to fast-track to complete their studies sooner.

OPIT was pleased with its success in making the courses international and accessible, with notable representation from Africa. In the first cohort, 40% of MSc students were also from non-STEM fields, showing OPIT’s success at engaging professionals looking to develop skills for the modern workplace.

July 2024: A Growing Curriculum

Building on this initial success, in 2024, OPIT expanded its academic offering to include a second BSc program in Digital Business, and three new MSc programs in Digital Business & Innovation, Responsible Artificial Intelligence, and Enterprise Cybersecurity. These were all offered in addition to the original two programs.

The new course offerings led to total student numbers growing to over 300, hailing from 78 different countries. This also led to an expansion of the faculty, with professionals recruited from major business leaders such as Symantec, Microsoft, PayPal, McKinsey, MIT, Morgan Stanley, Amazon, and U.S. Naval Research. This focus on professional experience and real-world applications is ideal for OPIT as 80% of the student body are active working professionals.

January 2025: First Graduating Class

OPIT held its first-ever graduation ceremony in Valletta, Malta, on March 8, 2025. The ceremony was a hybrid event, with students attending both in person and virtually. The first graduating class consisted of 40 students who received an MSc in Applied Data Science and AI.

OPIT’s MSc programs include a capstone project that sees students apply their learning to real-world challenges. Projects included the use of large language models for the creation of chatbots in the ed-tech field, the digitalization of customer support processes in the paper and non-woven industry, personal data protection systems, AI applications for environmental sustainability, and predictive models for disaster prevention linked to climate change. Since many OPIT students realized their capstone projects within their organizations, OPIT also saw itself successfully facilitating digital innovation in the field.

July 2025: New Learning Environments

The next step for OPIT is not just to teach others how to leverage AI to work smarter, but to start applying AI solutions in our own business environment. To this end, OPIT unveiled its OPIT AI Copilot at the Microsoft AI Agents and the Future of Higher Education event in Milan in June 2025.

The OPIT AI Copilot is a specialist AI Agent designed to enhance learning in OPIT’s fully digital environment. OPIT AI Copilot acts as a personal tutor and study companion, and but rather than being trained on the World Wide Web, it is specifically trained on OPIT’s educational archive of around 3,500 hours of lectures and 3,000 proprietary documents.

The OPIT AI Copilot then provides real-time, personalized guidance that adapts to where the student is in the course and the progress they have shown in grasping the material. As well as pulling from existing materials, the OPIT AI Copilot can generate content to deepen learning, such as code samples and practical exams. It can also answer questions posed by the students with answers grounded in the official course material. The tool is available 24/7, and also has an intelligent examination mode, which prevents cheating.

In this way, OPIT AI Copilot enriches the OPIT learning environment by providing students with 24/7 personalized support for their learning journey, ideal for busy professionals balancing work and study. It is a step towards facing the challenge of “one-size-fits-all” education approaches that have plagued learning institutions for millennia.

September 2025: A New Cohort

On the heels of the OPIT AI Copilot launch, OPIT is excited about recruiting its next round of students, with applications open until September 2025. If you are interested in joining OPIT, you can learn more about its courses here.

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Authority Magazine: Paola Tirelli of RWS Group on the Future of Artificial Intelligence
OPIT - Open Institute of Technology
OPIT - Open Institute of Technology
Aug 4, 2025 9 min read

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By Kate Mowbray, 7 min read


“To engage more women in the AI industry, I believe we need to start by highlighting the diversity of roles available. Not all of them are purely technical. AI needs linguists, designers, ethicists, project managers, and many other profiles. Showing that there’s space for different kinds of expertise can make the field feel more accessible. We also need more visible role models: women who are leading, innovating, and mentoring in AI.”

As part of our series about the future of Artificial Intelligence, I had the pleasure of interviewing Paola Tirelli, linguistic AI specialist with RWS Group. Paola is also an MSc in Applied Data Science and AI graduate of OPIT — Open Institute of Technology, a global online educational institution.

With over a decade in translation and project management, Paola is passionate about integrating technology with language services. She considers bridging language barriers and leading teams to success her strength.

Thank you so much for joining us in this interview series! Can you share with us the ‘backstory” of how you decided to pursue this career path in AI?

Mybackground is in linguistics and localization, and I’ve spent years working with translation, quality assurance, and automation tools. I’ve always been fascinated by the intersection of language and technology. The turning point came when I realized I had reached a plateau in my role and felt a strong urge to grow, contribute more meaningfully, and understand the changes reshaping the industry.

That curiosity naturally led me to AI, a space where my linguistic expertise could meet innovation. I began to see how powerful AI could be in solving specific challenges in localization, especially around quality and efficiency. This inspired me to pursue a Master’s in Applied Data Science and AI at OPIT, to deepen my skills and explore how to bridge my domain knowledge with the new tools AI offers.

What lessons can others learn from your story?

It’s never too late to reinvent yourself. You don’t need to have a technical background from the start to enter the AI field. With strong motivation, curiosity, and a willingness to learn, you can go very far.

Embracing your own expertise, whatever it may be, can actually become your greatest asset. AI isn’t just about code and algorithms; it’s about solving real-world problems, and that requires diverse perspectives. If you’re driven by purpose and open to growth, you can not only adapt to change, but you can help shape it.

Can you tell our readers about the most interesting projects you are working on now?

What I find most exciting about my current work is the opportunity to experiment and explore where AI can truly be a game changer in the localization space. I’m particularly interested in projects that would have been unthinkable just a few years ago, initiatives involving massive amounts of data or complex workflows that no client would have considered feasible due to time, cost, or resource constraints. Thanks to AI, we can now approach these challenges in entirely new ways, unlocking value and enabling solutions that were previously out of reach, such as automated terminology extraction or adapting content across different language variants.

None of us are able to achieve success without some help along the way. Is there a particular person who you are grateful towards who helped get you to where you are? Can you share a story about that?

I’m especially grateful to the person who would later become my manager, Marina Pantcheva. At the time, I had already started my Master’s at OPIT and was looking for the right direction to apply what I was learning. I knew I wanted to stay within my company, but I wasn’t sure where to focus.

Then I attended a talk she gave on AI. It was clear, engaging, and incredibly inspiring. It felt like a calling. I knew I wanted to work with her and be part of her team. When I eventually joined the AI team, she believed in my potential from the start. She gave me the space to ask questions, explore ideas, and gradually take on more responsibility. That trust and support made all the difference. It helped me grow into this new field with confidence and purpose.

What are the 5 things that most excite you about the AI industry? Why?

· We’re writing the future — AI is still in its early stages, and we don’t yet know the limits of what it can do. Being part of this journey feels like contributing to something truly transformative.

· Unthinkable opportunities are now possible — Tasks that once required enormous manual effort or were simply out of reach due to scale or complexity are now achievable. AI opens doors to projects that were previously unimaginable.

· Access to knowledge like never before — AI enhances how we interact with information, making it faster and more intuitive to explore, learn, and apply knowledge across domains.

· Cross-disciplinarity — AI touches every field, so it’s full of opportunities for people from different backgrounds.

· Problem-solving at scale — AI can help automate tedious tasks and improve decision-making in complex workflows.

What are the 5 things that concern you about the AI industry? Why?

· AI systems are not 100% reliable, and their outputs can sometimes be inaccurate or misleading. This raises questions about how much we can (or should) trust them, especially in high-stakes contexts.

· As we integrate AI into more aspects of our work and lives, there’s a risk of becoming overly reliant on it, potentially at the expense of human judgment, creativity, and critical thinking.

· If we delegate too much to machines, we may gradually lose some of our own cognitive abilities, like problem-solving, memory, or even language skills, simply because we’re not exercising them as much.

· Without clear communication and reskilling strategies, AI can be perceived as a threat rather than a tool. This fear can create resistance and anxiety, especially in industries undergoing rapid transformation.

· From bias in algorithms to the misuse of generative tools, the ethical challenges are real. We need strong frameworks to ensure AI is developed and used responsibly, with transparency and accountability.

As you know, there is an ongoing debate between prominent scientists, (personified as a debate between Elon Musk and Mark Zuckerberg,) about whether advanced AI poses an existential danger to humanity. What is your position about this?

I think it’s important to separate science fiction from science. While I don’t believe current AI poses an existential threat, I do believe that we need to be very intentional about how we develop and use it. The real risks today are more about misuse, bias, and lack of transparency than about a doomsday scenario.

What can be done to prevent such concerns from materializing? And what can be done to assure the public that there is nothing to be concerned about?

Transparency and education are key. We need to involve more people in the conversation; not just engineers, but also linguists, ethicists, teachers, and everyday users. Clear communication about what AI can and cannot do would help build trust. Regulation also has to catch up with the speed of innovation, without stifling it.

As you know, there are not many women in the AI industry. Can you advise what is needed to engage more women into the AI industry?

My perception is slightly different, because I come from the localization industry, where there’s a strong presence of women. So, when I transitioned into AI, I brought with me a sense of belonging and confidence that not everyone may feel when entering a more male-dominated space.

To engage more women in the AI industry, I believe we need to start by highlighting the diversity of roles available. Not all of them are purely technical. AI needs linguists, designers, ethicists, project managers, and many other profiles. Showing that there’s space for different kinds of expertise can make the field feel more accessible. We also need more visible role models: women who are leading, innovating, and mentoring in AI.

Representation matters. When you see someone like you doing something you thought was out of reach, it becomes easier to imagine yourself there too.

What is your favorite “Life Lesson Quote”? Can you share a story of how that had relevance to your own life?

It’s never too late to be what you might have been,” by George Eliot.

This quote really resonated with me when I decided to shift my career path toward AI. Starting a Master’s in Applied Data Science and AI while working full-time wasn’t easy, but that quote gave me the courage to step into a field that initially felt far from my comfort zone, and to trust that my unique background could actually be a strength, not a limitation.

You are a person of great influence. If you could start a movement that would bring the most amount of good to the most amount of people, what would that be? You never know what your idea can trigger.

If I could start a movement, it would focus on democratizing access to AI education and tools, especially for people from non-technical backgrounds. I truly believe that AI should not be limited to engineers or data scientists. It has the potential to empower professionals from all fields, from linguists to educators to healthcare workers. I’d love to see a world where people feel confident using AI not just as a tool, but as a partner in creativity, problem-solving, and innovation, regardless of their background, gender, or location.

How can our readers further follow your work online?

I usually share updates on LinkedIn: https://www.linkedin.com/in/paola-tirelli-9abbb32a9/

This was very inspiring. Thank you so much for joining us!

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