An ER diagram in DBMS (database management systems) is a lot like a storyboard for an animated TV show – it’s a collection of diagrams that show how everything fits together. Where a storyboard demonstrates the flow from one scene to the next, an ER diagram highlights the components of your databases and the relationships they share.

Understanding the ER model in DBMS is the first step to getting to grips with basic database software (like Microsoft Access) and more complex database-centric programming languages, such as SQL. This article explores ER diagrams in detail.

ER Model in DBMS

An ER diagram in DBMS is a tangible representation of the tables in a database, the relationships between each of those tables, and the attributes of each table. These diagrams feature three core components:

  • Entities – Represented by rectangles in the diagram, entities are objects or concepts used throughout your database.
  • Attributes – These are the properties that each entity possesses. ER diagrams use ellipses to represent attributes, with the attributes themselves tending to be the fields in a table. For example, an entity for students in a school’s internal database may have attributes for student names, birthdays, and unique identification numbers.
  • Relationships – No entity in an ER diagram is an island, as each is linked to at least one other. These relationships can take multiple forms, with said relationships dictating the flow of information through the database.

Mapping out your proposed database using the ER model is essential because it gives you a visual representation of how the database works before you start coding or creating. Think of it like the blueprint you’d use to build a house, with that blueprint telling you where you need to lay every brick and fit every door.

Entities in DBMS

An Entity in DBMS tends to represent a real-life thing (like the students mentioned previously) that you can identify with certain types of data. Each entity is distinguishable from the others in your database, meaning you won’t have multiple entities listing student details.

Entities come in two flavors:

  • Tangible Entities – These are physical things that exist in the real world, such as a person, vehicle, or building.
  • Intangible Entities – If you can see and feel an entity, it’s intangible. Bank accounts are good examples. We know they exist (and have data attributed to them) but we can’t physically touch them.

There are also different entity strengths to consider:

  • Strong Entities – A strong entity is represented using a rectangle and will have at least one key attribute attached to it that allows you to identify it uniquely. In the student example we’ve already shared, a student’s ID number could be a unique identifier, creating a key attribute that leads to the “Student” entity being strong.
  • Weak Entities – Weak entities have no unique identifiers, meaning you can’t use them alone. Represented using double-outlined rectangles, these entities rely on the existence of strong entities to exist themselves. Think of it like the relationship between parent and child. A child can’t exist without a parent, in the same way that a weak entity can’t exist without a strong entity.

Once you’ve established what your entities are, you’ll gather each specific type of entity into an entity set. This set is like a table that contains the data for each entity in a uniform manner. Returning to the student example, any entity that has a student ID number, name, and birthdate, may be placed into an overarching “Student” entity set. They’re basically containers for specific entity types.

Attributes in DBMS

Every entity you establish has attributes attached to it, as you’ve already seen with the student example used previously. These attributes offer details about various aspects of the entity and come in four types:

  • Simple Attributes – A simple attribute is any attribute that you can’t break down into further categories. A student ID number is a good example, as this isn’t something you can expand upon.
  • Composite Attributes – Composite attributes are those that may have other attributes attached to them. If “Name” is one of your attributes, its composites could be “First Name,” “Surname,” “Maiden Name,” and “Nickname.”
  • Derived Attributes – If you can derive an attribute from another attribute, it falls into this category. For instance, you can use a student’s date of birth to derive their age and grade level. These attributes have dotted ellipses surrounding them.
  • Multi-valued Attributes – Represented by dual-ellipses, these attributes cover anything that can have multiple values. Phone numbers are good examples, as people can have several cell phone or landline numbers.

Attributes are important when creating an ER model in DBMS because they show you what types of data you’ll use to populate your entities.

Relationships in DBMS

As your database becomes more complex, you’ll create several entities and entity sets, with each having relationships with others. You represent these relationships using lines, creating a network of entities with line-based descriptions telling you how information flows between them.

There are three types of relationships for an ER diagram in DBMS:

  • One-to-One Relationships – You’ll use this relationship when one entity can only have one of another entity. For example, if a school issues ID cards to its students, it’s likely that each student can only have one card. Thus, you have a one-to-one relationship between the student and ID card entities.
  • One-to-Many Relationships – This relationship type is for when one entity can have several of another entity, but the relationship doesn’t work in reverse. Bank accounts are a good example, as a customer can have several bank accounts, but each account is only accessible to one customer.
  • Many-to-Many Relationships – You use these relationships to denote when two entities can have several of each other. Returning to the student example, a student will have multiple classes, with each class containing several students, creating a many-to-many relationship.

These relationships are further broken down into “relationship sets,” which bring together all of the entities that participate in the same type of relationship. These sets have three varieties:

  • Unary – Only one entity participates in the relationship.
  • Binary – Two entities are in the relationship, such as the student and course example mentioned earlier.
  • n-ary – Multiple entities participate in the relationship, with “n” being the number of entities.

Your ER diagram in DBMS needs relationships to show how each entity set relates to (and interacts with) the others in your diagram.

ER Diagram Notations

You’ll use various forms of notation to denote the entities, attributes, relationships, and the cardinality of those relationships in your ER diagram.

Entity Notations

Entities are denoted using rectangles around a word or phrase, with a solid rectangle meaning a strong entity and a double-outlined rectangle denoting a weak entity.

Attribute Notations

Ellipses are the shapes of choice for attributes, with the following uses for each attribute type:

  • Simple and Composite Attribute – Solid line ellipses
  • Derived Attribute – Dotted line ellipses
  • Multi-Valued Attribute – Double-lined ellipses

Relationship Notations

Relationship notation uses diamonds, with a solid line diamond depicting a relationship between two attributes. You may also find double-lined diamonds, which signify the relationship between a weak entity and the strong entity that owns it.

Cardinality and Modality Notations

These lines show you the maximum times an instance in one entity set can relate to the instances of another set, making them crucial for denoting the relationships inside your database.

The endpoint of the line tells you everything you need to know about cardinality and ordinality. For example, a line that ends with three lines (two going diagonally) signifies a “many” cardinality, while a line that concludes with a small vertical line signifies a “one” cardinality. Modality comes into play if there’s a minimum number of instances for an entity type. For example, a person can have many phone numbers but must have at least one.

Steps to Create an ER Diagram in DBMS

With the various notations for an ER diagram in DBMS explained, you can follow these steps to draw your own diagram:

  • Identify Entities – Every tangible and intangible object that relates to your database is an entity that you need to identify and define.
  • Identify Attributes – Each entity has a set of attributes (students have names, ID numbers, birthdates, etc.) that you must define.
  • Identify Relationships – Ask yourself how each entity set fits together to identify the relationships that exist between them.
  • Assign Cardinality and Modality – If you have an instance from Entity A, how many instances does it relate to in Entity B? Is there a minimum to consider? Assign cardinalities and modalities to offer the answers.
  • Finalize Your Diagram – Take a final pass over the diagram to ensure all required entities are present, they have the appropriate attributes, and that all relationships are defined.

Examples of ER Diagrams in DBMS

Once you understand the basics of the ER model in DBMS, you’ll see how they can apply to multiple scenarios:

  • University Databases – A university database will have entities such as “Student,” “Teacher,” “Course,” and “Class.” Attributes depend on the entity, with the people-based entities having attributes including names, dates of birth, and ID numbers. Relationships vary (i.e., a student may only have one teacher but a single teacher may have several students).
  • Hospital Management Databases – Entities for this type of database include people (“Patients,” “Doctors,” and “Nurses”), as well as other tangibles, such as different hospital buildings and inventory. These databases can get very complex, with multiple relationships linking the various people involved to different buildings, treatment areas, and inventory.
  • E-Commerce Databases – People play an important role in the entities for e-commerce sites, too, because every site needs a list of customers. Those customers have payment details and order histories, which are potential entities or attributes. Product lists and available inventory are also factors.

Master the ER Model in DBMS

An ER diagram in DBMS can look like a complicated mass of shapes and lines at first, making them feel impenetrable to those new to databases. But once you get to grips with what each type of shape and line represents, they become crucial tools to help you outline your databases before you start developing them.

Application of what you’ve learned is the key to success with ER diagrams (and any other topic), so take what you’ve learned here and start experimenting. Consider real-world scenarios (such as those introduced above) and draw diagrams based on the entities you believe apply to those scenarios. Build up from there to figure out the attributes and relationships between entity sets and you’re well on your way to a good ER diagram.

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Il Sole 24 Ore: 100 thousand IT professionals missing
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Written on April 24th 2024

Source here: Il Sole 24 Ore (full article in Italian)

Open Institute of Technology: 100 thousand IT professionals missing

Eurostat data processed and disseminated by OPIT. Stem disciplines: the share of graduates in Italy between the ages of 20 and 29 is 18.3%, compared to the European 21.9%

Today, only 29% of young Italians between 25 and 34 have a degree. Not only that: compared to other European countries, the comparison is unequal given that the average in the Old Continent is 46%, bringing Italy to the penultimate place in this ranking, ahead only of Romania. The gap is evident even if the comparison is limited to STEM disciplines (science, technology, engineering and mathematics) where the share of graduates in Italy between the ages of 20 and 29 is 18.3%, compared to the European 21.9%, with peaks of virtuosity which in the case of France that reaches 29.2%. Added to this is the continuing problem of the mismatch between job supply and demand, so much so that 62.8% of companies struggle to find professionals in the technological and IT fields.

The data

The Eurostat data was processed and disseminated by OPIT – Open Institute of Technology. an academic institution accredited at European level, active in the university level education market with online Bachelor’s and Master’s degrees in the technological and digital fields. We are therefore witnessing a phenomenon with worrying implications on the future of the job market in Italy and on the potential loss of competitiveness of our companies at a global level, especially if inserted in a context in which the macroeconomic scenario in the coming years will undergo a profound discontinuity linked to the arrival of “exponential” technologies such as Artificial Intelligence and robotics, but also to the growing threats related to cybersecurity.

Requirements and updates

According to European House Ambrosetti, over 2,000,000 professionals will have to update their skills in the Digital and IT area by 2026, also to take advantage of the current 100,000 vacant IT positions, as estimated by Frank Recruitment Group. But not only that: the Italian context, which is unfavorable for providing the job market with graduates and skills, also has its roots in the chronic birth rate that characterizes our country: according to ISTAT data, in recent years the number of newborns has fallen by 28%, bringing Italy’s birth rate to 1.24, among the lowest in Europe, where the average is 1.46.

Profumo: “Structural deficiency”

“The chronic problem of the absence of IT professionals is structural and of a dual nature: on one hand the number of newborns – therefore, potential “professionals of the future” – is constantly decreasing; on the other hand, the percentage of young people who acquires degrees are firmly among the lowest in Europe”, declared Francesco Profumo, former Minister of Education and rector of OPIT – Open Institute of Technology. “The reasons are varied: from the cost of education (especially if undertaken off-site), to a university offering that is poorly aligned with changes in society, to a lack of awareness and orientation towards STEM subjects, which guarantee the highest employment rates. Change necessarily involves strong investments in the university system (and, in general, in the education system) at the level of the country, starting from the awareness that a functioning education system is the main driver of growth and development in the medium to long term. It is a debated and discussed topic on which, however, a clear and ambitious position is never taken.”

Stagnant context and educational offer

In this stagnant context, the educational offer that comes from online universities increasingly meets the needs of flexibility, quality and cost of recently graduated students, university students looking for specialization and workers interested in updating themselves with innovative skills. According to data from the Ministry of University and Research, enrollments in accredited online universities in Italy have grown by over 141 thousand units in ten years (since 2011), equal to 293.9%. Added to these are the academic institutions accredited at European level, such as OPIT, whose educational offering is overall capable of opening the doors to hundreds of thousands of students, with affordable costs and extremely innovative and updated degree paths.

Analyzing the figures

An analysis of Eurostat statistics relating to the year 2021 highlights that 27% of Europeans aged between 16 and 74 have attended an entirely digital course. The highest share is recorded in Ireland (46%), Finland and Sweden (45%) and the Netherlands (44%). The lowest in Romania (10%), Bulgaria (12%) and Croatia (18%). Italy is at 20%. “With OPIT” – adds Riccardo Ocleppo, founder and director – “we have created a new model of online academic institution, oriented towards new technologies, with innovative programs, a strong practical focus, and an international approach, with professors and students from 38 countries around the world, and teaching in English. We intend to train Italian students not only on current and updated skills, but to prepare them for an increasingly dynamic and global job market. Our young people must be able to face the challenges of the future like those who study at Stanford or Oxford: with solid skills, but also with relational and attitudinal skills that lead them to create global companies and startups or work in multinationals like their international colleagues. The increasing online teaching offer, if well structured and with quality, represents an incredible form of democratization of education, making it accessible at low costs and with methods that adapt to the flexibility needs of many working students.”

Point of reference

With two degrees already starting in September 2023 – a three-year degree (BSc) in Modern Computer Science and a specialization (MSc) in Applied Data Science & AI – and 4 starting in September 2024: a three-year degree (BSc) in Digital Business, and the specializations (MSc) in Enterprise Cybersecurity, Applied Digital Business and Responsible Artificial Intelligence (AI), OPIT is an academic institution of reference for those who intend to respond to the demands of a job market increasingly oriented towards the field of artificial intelligence. Added to this are a high-profile international teaching staff and an exclusively online educational offer focused on the technological and digital fields.

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Times of India: The 600,000 IT job shortage in India and how to solve it
OPIT - Open Institute of Technology
OPIT - Open Institute of Technology
May 2, 2024 3 min read

Written on April 25th 2024

Source here: Times of India 

The job market has never been a straightforward path. Ask anyone who has ever looked for a job, certainly within the last decade, and they can tell you as much. But with the rapid development of AI and machine learning, concerns are growing for people about their career options, with a report from Randstad finding that 7 in 10 people in India are concerned about their job being eliminated by AI.

 Employers have their own share of concerns. According to The World Economic Forum, 97 million new AI-related jobs will be created by 2025 and the share of jobs requiring AI skills will increase by 58%. The IT industry in India is experiencing a tremendous surge in demand for skilled professionals on disruptive technologies like artificial intelligence, machine learning, blockchain, cybersecurity and, according to Nasscom, this is leading to a shortage of 600,000 profiles.

 So how do we fill those gaps? Can we democratize access to top-tier higher education in technology?

These are the questions that Riccardo Ocleppo, the engineer who founded a hugely successful ed-tech platform connecting international students with global Universities, Docsity, asked himself for years. Until he took action and launched the Open Institute of Technology (OPIT), together with the Former Minister of Education of Italy, Prof. Francesco Profumo, to help people take control of their future careers.

OPIT offers BSc and MSc degrees in Computer Science, AI, Data Science, Cybersecurity, and Digital Business, attracting students from over 38 countries worldwide. Through innovative learning experiences and affordable tuition fees starting at €4,050 per year, OPIT empowers students to pursue their educational goals without the financial and personal burden of relocating.

The curriculum, delivered through a mix of live and pre-recorded lectures, equips students with the latest technology skills, as well as business and strategic acumen necessary for careers in their chosen fields. Moreover, OPIT’s EU-accredited degrees enable graduates to pursue employment opportunities in Europe, with recognition by WES facilitating transferability to the US and Canada.

OPIT’s commitment to student success extends beyond academics, with a full-fledged career services department led by Mike McCulloch. Remote students benefit from OPIT’s “digital campus,” fostering connections through vibrant discussion forums, online events, and networking opportunities with leading experts and professors.

Faculty at OPIT, hailing from prestigious institutions and industry giants like Amazon and Microsoft, bring a wealth of academic and practical experience to the table. With a hands-on, practical teaching approach, OPIT prepares students for the dynamic challenges of the modern job market.

In conclusion, OPIT stands as a beacon of hope for individuals seeking to future-proof their careers in technology. By democratizing access to high-quality education and fostering a global learning community, OPIT empowers students to seize control of their futures and thrive in the ever-evolving tech landscape.

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