In the present fast-paced era, recording keeping is pretty straightforward with the concept of computer-based databases. The database stores the information of all the entities in a structural manner. Structural diagrams are used to represent the information stored in a database. In this context, ERD can be considered the most common example of a structural diagram.
Given the ERD’s immense importance, ER diagram online creation is quite common nowadays. In addition, several tools facilitate the users in designing ERD even without internet connectivity. To make the ERD designing concept easier, here we have elaborated on the ER diagram tutorial in detail.
1. ER Diagrams
ER or entity-relationship diagrams are employed to represent the visual relationship between different entities. You may already be familiar with the basic structure of an ERD, as it mainly consists of entities, attributes and relationships.
An entity can be anything conceptual or physical, i.e. people, buildings, results, materials, things, places, etc., that can be classified as weak or strong entities in the database management system. The attributes are considered the characteristics of entities, and each entity must have at least one attribute in an ER diagram.
How To Make ER Diagrams?
ER diagram designing isn’t a complex endeavour if you have a clear understanding of the entities of the respective system. To design a comprehensive entity relation diagram, you can go for ER diagram online creation, or you can opt for a diagramming tool to have a smooth ER diagramming experience.
In an entity relationship diagram, rectangular boxes are used to represent the entities and elliptical shapes are used for attributes. Relationships can be established between different entities using arrow lines. However, note that the relationships can be of various types denoted by different symbols such as one-to-one, one-to-many, many-to-many, mandatory and optional.
2. How To Make ER Diagrams With EdrawMax?
You can come across multiple choices regarding ER diagram online creation. Numerous online platforms assist in designing entity relationship diagrams, but not all are equally user-friendly. You must consider an efficient & easy to use platform so that the entity relationship diagram design doesn’t seem challenging.
Against this backdrop, EdrawMax is considered the most optimum choice that not only facilitates designing afresh ERD but also presents an extensive templates community to simplify the designing process significantly.
How to create an ER diagram
Step 1: Identify the entities: In the first step, identify the entities present within the system. Entities are distinct tables or objects that store some type of information. An entity is represented using a rectangular box. The name of the entity is written within the box.
Step 2: Identify the attributes: Each entity has some properties that define it. Identify these properties or attributes associated with an entity. An attribute is represented using an oval-shaped link to the entity.
Step 3: Determine relationship: The next step is to identify the relationship that exists among the entities. A relationship defines how two entities interact with one another. A relationship is represented using a diamond shape.
Step 4: Assign primary key: Each entity is identified by a primary key. It is used to identify an entity within a set of entities. A primary key is represented using an underlined symbol.
Step 5: Establish foreign key references: A foreign key is used to link two inter-related entities using a reference. It is denoted using the keyword {FK} written within parenthesis.
Step 6: Review the diagram: Review the entities, attributes, and relationships that exist within the system. Refine it such that it meets the requirements of the system.
3. Best Templates of ER Diagram Online
Though we have thoroughly elaborated on how to make an entity relationship diagram online using a top-notch diagramming tool, EdrawMax, still designing a complex or high-level diagram may seem quite a time-consuming & hectic job. In such a case, you can opt for EdrawMax’s editable templates to instantly craft a customise ER diagram online.
- Example 1: University System ER Diagram
- Example 2: Movie Production ER Diagram
- Example 3: Website Database ER Diagram
- Example 4: Sales & Purchase ER Diagram
- Example 5: Players System ER Diagram
- Example 6: Tour Office ER Diagram
- Example 7: Film Production ER Diagram
- Example 8: Hospital Management ER Diagram
- Example 9: School Management System ER Diagram
University System ER Diagram
below. 
The presented university system diagram encompasses various entities like centres, staff, departments, guardians, sessions, school sessions, users, students, guardian students, classes, classes_students, and school holidays. All the entities have relevant attributes added below them.
You can understand the concept of the relationship between these entities by the given notations or symbols. For instance, centres can have a minimum of one or a maximum of many students, staff and sessions. In contrast, the students, staff and sessions entities can be associated with only one centre.
Movie Production ER Diagram
The movie production process involves many entities, as shown in the above ER diagram template, i.e., users, u2base, movies, movie2directors, movies2actors, actors and directors. Users have one and many relationships with u2base, while u2base can have only one user. Movies entity has one or many relationships with u2base, movie2director and movies2actors; contrarily, all these can have only one relationship with the Movie entity.
Website Database ER Diagram
A website’s database can be vast, often making it hard to perceive. Therefore, creating an ERD is the ultimate solution to sort out such a hassle. The given website database ER diagram comprehensively illustrates how a website’s data is stored in a database.
It’s a high-level and complex ERD that consists of various entities, i.e., systems, surveys, locations, users, titles, taxa etc., and you can customise it as needed.
Sales & Purchase ER Diagram
The sales and purchase ER diagram is pretty straightforward, consisting of six entities customer, company, e-commerce, shipping, item and shopping cart. The diagram shows the company produces items based on the customer’s order. The e-commerce system processes the items the customer has added to the shipping cart for shipping purposes. This is how the entire sales & purchases process over the internet work.
Players System ER Diagram
A player’s system ERD can be used to visualise players’ activities. In this diagram, four entities have been shown along with their relationships. A player, team and matches entities can have a minimum of zero and a maximum of many actions.
If considering the Action Entity, it can be associated with only one player & match. In contrast, it can have zero or one relation with the team entity.
Tour Office ER Diagram
The tour office ER diagram demonstrates the complete picture of a tour office and its operational phases. The diagram depicts that a tour officer can have zero or many drivers and tour guides. Still, drivers & tour guides can only have one tour officer. The tour guide’s job involves checking the tour, verifying the returns, booking seats, confirming the accommodation and finally confirming the destination.
Film Production ER Diagram
A film production ER diagram simplifies the processes involved in the film production phase by clearly demonstrating all the entities and their relationship with each other. For instance, the given ERD template depicts how payment, actor, film, customer, inventory and other related entities are linked to each other. The occurrence of relationships between these entities is illustrated in lines and notations.
Hospital Management ER Diagram
A visual illustration of the Hospital management system assists a lot in understanding the relationship between doctor & patient and how the administration registers patients and keeps their medical records.
In this context, patients, doctors, head offices, administration and medical records can be considered the main entities of this hospital management system. You can easily employ & customise the above ERD template to reuse it in a similar scenario.
School Management System ER Diagram
The given entity relationship diagram of the school management system depicts that a classroom can have only one teacher. Still, the teacher can teach in many classrooms. Likewise, the classroom can be associated with many subjects and students. In contrast, the subject and student entity can be linked to one classroom. Each classroom has one timetable. Contrarily, the timetable entity can be associated with many classrooms.
4. Conclusion
ER diagram indicates the flowcharts used to represent the relationships of entities with other entities. You can relate the ER concept to databases since ER diagrams are mainly used to render the data or information stored in a DB to ease data comprehension.
In this connection, here we have presented detailed insights into the ER diagrams and illustrated how to draw ER diagrams using an efficient tool like EdrawMax. You can also go for the ERD pre-built templates as a time-saving approach complementarily.
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