E-R Diagrams

Complexity of databases increases day by day, due to this the Entity relationship models and E-R diagrams become more and more popular, and now are an important part of database design. E-R diagrams allow visually and graphically represent structure and design of databases.

You can use so popular Chen's notation to represent all components of database and their relationships on the ER diagram. This notation was developed and implemented by Peter Chen in 1976. The main components of the E-R diagrams are:

  • entities,
  • attributes that describe these entities,
  • relationships among these entities that describe associations between the data,
  • cardinalities that describe the number of relationship participants: one-to-many (1:M), many-to-many (M:N), and one-to-one (1:1).

In a Chen's notation, entities are represented by rectangles on the diagram with the entity names written inside and relationships are represented by diamonds. Another popular type of E-R diagrams is known as Crow's Foot notation that is derived from the Chen's notation.

E-R Diagram - Students and teachers

Example 1. E-R Diagram - Students and teachers

Use of ConceptDraw PRO for professional ERD drawing includes using the predesigned components of ER diagram, such as entity relationship symbols, work flow shapes, entity relationship stencils. All they are provided for easy use by 2 libraries of Entity-Relationship Diagram (ERD) Solution from the Software Development Area for ConceptDraw Solution Park.

ERD Libraries

Example 2. ERD Libraries

There is also wide collection of predesigned E-R Diagrams which is represented at ConceptDraw STORE. All E-R Diagrams samples and templates are well thought-out, professionally designed, can be easy changed according to your needs and further successfully used.

E-R Diagrams

Example 3. E-R Diagrams in ConceptDraw PRO

The following features make ConceptDraw PRO extended with the Entity-Relationship Diagram (ERD) solution the most effective E-R diagrams design software:

  1. You don't need to be an artist to draw professional looking diagrams in a few minutes.
  2. Large quantity of ready-to-use vector objects makes drawing your diagrams quick and easy.
  3. Extensive collection of pre-designed templates and samples give you a great start for your own diagrams.
  4. ConceptDraw PRO provides you with the possibility to use the grid, rules and guides. You can easily rotate, group, align, and arrange objects, and use different fonts and colors to make your diagram stand out.
  5. All ConceptDraw PRO documents are vector graphic files and are available for reviewing, modifying, and converting to a variety of formats: image, HTML, PDF file, MS PowerPoint Presentation, Adobe Flash, MS Visio.
  6. Using ConceptDraw STORE you can navigate through ConceptDraw Solution Park, managing downloads and updates. You can access libraries, templates and samples directly from ConceptDraw STORE.
  7. If you have any questions, our support is free of charge and always ready to come to your aid.






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TEN RELATED HOW TO's:

ConceptDraw PRO ER Diagram Tool

Database design is an important part of any project, as databases become more and more complex nowadays. To make the model more representative, entity relationship diagrams are widely used in software engineering area. These diagrams show sets of entities as rectangles connected via lines labeled with their cardinalities. This an example of the ER-diagram developed to store information regarding some online role-playing game. It includes three main elements of ER diagram: entities, relationships and attributes. The entities, attributes and relationships on this ER-diagram is depicted according to the Chen's notation. Chen's notation for Entity Relationship diagrams admits using of rectangles to depict entities, ovals for attributes and ,at least, diamonds to show relationships . ConceptDraw Entity-Relationship Diagrams solution was applied as ERD software to create this diagram.ER Diagram Tool. Chen ERD
Picture: ConceptDraw PRO ER Diagram Tool
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Entity Relationship Diagram Examples

An abstract representation is usually the first thing you will need while developing a database. To understand the ways that databases are structured, you should look through entity-relationship diagram examples and see the notations features and attributes. With an entity-relationship model you can describe a database of any complexity. This Entity-relationship diagram is a tool for software developers. It enables every element of database to be managed, communicated and tested before release. This ERD was created using symbols advocated by Chen's notation. Because of a linguistic origin of the Chen’s notation, the boxes representing entities could be interpreted as nouns, and the relationships between them are in verb form, shown on a diagram as a diamond.Entity Relationship Diagram Examples
Picture: Entity Relationship Diagram Examples
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ERD Symbols and Meanings

A database is a data collection, structured into some conceptual model. Two most common approaches of developing data models are UML diagrams and ER-model diagrams. There are several notations of entity-relationship diagram symbols and their meaning is slightly different. Crow’s Foot notation is quite descriptive and easy to understand, meanwhile, the Chen notation is great for conceptual modeling. An entity relationship diagrams look very simple to a flowcharts. The main difference is the symbols provided by specific ERD notations. There are several models applied in entity-relationship diagrams: conceptual, logical and physical. Creating an entity relationship diagram requires using a specific notation. There are five main components of common ERD notations: Entities, Actions, Attributes, Cardinality and Connections. The two of notations most widely used for creating ERD are Chen notation and Crow foot notation. By the way, the Crow foot notation originates from the Chen notation - it is an adapted version of the Chen notation.Entity Relationship Diagram Symbols and Meaning - crow
Picture: ERD Symbols and Meanings
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UML Notation

There are many ways to track the system in a critical situation. To model a system behavior, uml notation is widely used. Usually, an UML diagram consists of elements such as actor and a case. This diagram represents the structure of UML notations. Unified Modeling Language (UML) is used in software engineering to depict graphically the software modeling process. UM Language uses graphic notations for developing models of object-oriented systems. These notations displays requirements, sub-systems, logical and physical elements, etc. We created this diagram using ConceptDraw PRO reinforced with Rapid UML solution. It can be helpful for students on software engineering, when learning UML.uml diagram types list
Picture: UML Notation
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Entity-Relationship Diagram

Entity Relationship Diagram (ERD) is the world-known way to show the logical structure of databases in visual manner. The best software tool for drawing Entity-Relationship Diagram is ConceptDraw PRO vector graphics software with Entity-Relationship Diagram (ERD) solution from Software Development area which gives the ability to describe a database using the Entity-Relationship model. The vector graphic diagrams produced using this solution can be successfully used in whitepapers, presentations, datasheets, posters, or any technical materials.Entity-Relationship Diagram (ERD) - Students and Teachers
Picture: Entity-Relationship Diagram
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Business Process Modeling Notation Template

Create business process diagrams (BPMN 2.0.) with ConceptDraw using professional looking templates. ConceptDraw is business process improvement tools.Collaborative (public) B2B process diagram BPMN 2.0 - Cab booking process
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Entity Relationship Diagram Symbols

When we start to speak about databases, we must always mention database structure visualization. One of the most common ways to do it is to create an entity relationship diagram, and to put appropriate symbols on it. It is important either for database projecting and for its' future maintenance. Entity Relationship Diagram describes data elements and their relationships within a database. There are a set of special symbols that depict each element of an entity relationship diagram. Entities - represents some stable components such as supplier, employee, invoice, client, etc. Relation symbols show how the entities interact. Attributes define characteristics of the relationships. Attributes can be one-to-one or many-to-many. Physical symbols is used in the physical models. They represent items such as fields, tables, types and keys. ERD physical symbols are the building material for the database. Notation lines are used to illustrate the relationships. The most common method is Crow’s Feet notation. You can use ConceptDraw Entity-Relationship Diagram (ERD) solution to represent a database using the Entity-Relationship model.Entity Relationship Diagram Symbols
Picture: Entity Relationship Diagram Symbols
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UML Diagram Types List

Two types of diagrams are used in UML: Structure Diagrams and Behavior Diagrams. Behavior Diagrams represent the processes proceeding in a modeled environment. Structure Diagrams represent the elements that compose the system.UML class diagram of the AbstractFactory pattern
Picture: UML Diagram Types List
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UML Component Diagram. Design Elements

UML Component Diagram illustrates show components are wired together to larger components and software systems that shows the structure of arbitrarily complex systems. Rapid UML Solution for ConceptDraw PRO contains 13 vector stencils libraries with 393 interactive shapes that you can use to design your UML diagrams. To design a Component Diagram use the UML Component Diagram library. UML Component Diagram library contains 36 shapesUML Design Elements: Component (Win, Mac)
Picture: UML Component Diagram. Design Elements
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Entity Relationship Diagram Software Engineering

While designing a conceptual data model, you should use appropriate software. For instance, ConceptDraw PRO is a user-friendly ER diagram tool that has a lot of samples and templates to facilitate your work. A clear entity-relationship diagram helps to define the relations between system’s components. Software engineering is the section of a computer science engaged to design, realization, and support of complex software products. An ERD is a data modeling method that is widely applied in the software engineering practice. Commonly it is used for developing a structure of a a relational database. An entity relationship diagram is helpful for structuring and organizing databases that can be modeled using a relational structure. An entity relationship diagram is designed to depicts the interrelationships within the sets of entities which are accumulated in the database. Each entity represents a particular component of a data. Thus, ER diagrams depicts the logical structure of databases. ConceptDraw ER Diagrams solution provides software engineers with the professional tool for making entity-relationship diagrams.Entity Relationship Diagram Software Engineering
Picture: Entity Relationship Diagram Software Engineering
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