Entity Relationship Diagram Examples

Creation of Entity-Relationship (ER) model is a visual representation the structure of a business database, where data equates to entities or objects, which are linked by defined relationships expressing dependencies and requirements. By the nature, the ER model is an abstract visualization, a first step in design process towards creating a logical and functional database. ConceptDraw DIAGRAM professional software gives the ability to effectively describe a database using the Entity-Relationship model. Included to ConceptDraw Solution Park, the Entity-Relationship Diagram (ERD) solution contains the set of predesigned vector icons advocated by Chen's and Crow’s Foot notations that both can be used for data modeling and describing a database. Entity-Relationship Diagram (ERD) solution includes also helpful templates and incredibly large collection of varied Entity Relationship Diagram examples and samples offered at ConceptDraw STORE. Each of them can be used to develop your own model of a database of arbitrary complexity.

Entity Relationship Diagram Symbols

The semantic modeling method nowadays is successfully applied in database structure design. It is effective method of modeling the data structures, which is based on the meaning of these data. As a tool of semantic modeling, there are used different types of Entity-Relationship Diagrams. Entity Relationship Diagram (ERD) is applied to visually and clearly represent a structure of a business database. The main components of ERDs are: entity, relation and attributes. An entity is a class of similar objects in the model, each entity is depicted in the form of rectangle and has the name expressed by a noun. Relation is shown in the form of non-directional line that connects two entities. There are several notation styles used for ERDs: information engineering style, Chen style, Bachman style, Martin Style. The Entity Relationship Diagram symbols used for professional ERD drawing are predesigned by professionals and collected in the libraries of the Entity-Relationship Diagram (ERD) solution for ConceptDraw DIAGRAM software.

ERD Symbols and Meanings

Entity Relationship Diagram (ERD) is a popular software engineering tool for database modeling and illustration the logical structure of databases, which uses one of two notations - Chen's or Crow’s Foot. Crow's foot notation is effective when used in software engineering, information engineering, structured systems analysis and design. Each of these notations applies its own set of ERD symbols. Crow's foot diagrams use boxes to represent entities and lines between these boxes to show relationships. Varied shapes at the ends of lines depict the cardinality of a given relationship. Chen's ERD notation is more detailed way to represent entities and relationships. ConceptDraw DIAGRAM application enhanced with all-inclusive Entity-Relationship Diagram (ERD) solution allows design professional ER diagrams with Chen's or Crow’s Foot notation on your choice. It contains the full set of ready-to-use standardized ERD symbols and meanings helpful for quickly drawing, collection of predesigned ERD samples, examples and templates. ConceptDraw Pro is a great alternative to Visio for Mac users as it offers more features and can easily handle the most demanding professional needs.

Entity Relationship Diagram Software Engineering

Entity Relationship Diagram (aka ER Diagram, E-R Diagram, ERD) is a time-tested and widespread software development and software engineering method for data modeling, illustrating the logical structure of databases and system design. For ERDs construction are used three basic elements: entities, attributes, and relationships. Chen's notation for ERD supposes the use of rectangles (boxes) to represent entities and diamonds to depict relationships between first-class objects. This notation is popular when creating conceptual data models of information systems. Another standardized notation for ER diagrams is Crow's foot notation. ConceptDraw DIAGRAM as a powerful Entity Relationship Diagram software engineering provides the tools of Entity-Relationship Diagram (ERD) solution from Software Development area of ConceptDraw Solution Park for instantly describing databases using ERDs of Crow’s Foot and Chen’s notations. Use the predesigned vector elements for both these notations from 2 libraries included to Entity-Relationship Diagram (ERD) solution.

ConceptDraw DIAGRAM ER Diagram Tool

Entity-relationship model, also called ER-model, is the main tool of domain modeling on the stage of conceptual design. The modeling of domain data structures is based on the use of graphical tools - Entity-Relationship diagrams (ER-diagrams). The core concepts of ER-Diagram are entity, attribute and relationship. ER-diagram lets visually represent the entities, helps effectively document all properties of designed system and to detail the data storages. To represent the elements at ER-model are commonly used Chen’s notation and Crow’s foot notation, each has its pros and cons. The entity on ER-diagram is represented in the form of rectangle, which specifies its name. An attribute is a property of the entity and relationship is an interaction between the entities. The relationship between two entities is called binary, between more than two entities - ternary. Specific software, such as ConceptDraw DIAGRAM with Entity-Relationship Diagram (ERD) solution from ConceptDraw Solution Park is helpful for easy creation Entity-Relationship Diagrams.

Components of ER Diagram

Entity-Relationship model gives the possibility to visually describe a database using the components of ER Diagram, entity relationship stencils, relationship symbols, work flow shapes. ER-diagram lets represent the data or entities, attributes of these entities and relationships between them, using standardized Crow’s Foot notation icons or Chen’s notation icons. An entity is an object of the real world, it can exist independently and has the instances which differ in attribute values (properties). The attributes give an unambiguous (uniquely) identification for the instance and are called the primary key, this key can be composite and combine several attributes. ConceptDraw DIAGRAM is a professional software available with Entity-Relationship Diagram (ERD) solution from Software Development area that lets create ERDs for various database systems, using Crow’s Foot and Chen’s notations. It is invaluable tool for software engineers and developers, it supports ODBC-compatible databases (Oracle, MySQL, MS Access, MS SQL, InterBase, Firebird and others).

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 DIAGRAM ector 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.

How to Draw ER Diagrams

An Entity Relationship (ER) Diagram is a type of flowchart that illustrates the logical structure of databases, how the different entities, such as people, objects or concepts relate to each other within a given system. How to draw ER Diagrams fast and easy? ConceptDraw DIAGRAM diagramming and vector drawing software enhanced with Entity-Relationship Diagram (ERD) solution from Software Development area of ConceptDraw Solution Park offers you the powerful abilities of designing the ER Diagrams and ERD drawings without efforts. This solution includes a lot of predesigned icons advocated by popular Chen's and Crow’s Foot notations, which can be used when describing an enterprise database and depicting it by abstract way. Simply drag the required objects to ConceptDraw document, connect them in a desired way and make style settings. But the easiest and fastest way of drawing ERDs is to make them on the base of ready-to-use Chen ERD and Crow's Foot ERD templates, which are both represented at ConceptDraw STORE.

UML Diagram

The accepted open standard that is used in software engineering and system design, when modeling object-oriented systems and business processes is known as Unified Modeling Language (UML). UML was created for definition, visualization, design and documentation software systems. It isn't a programming language, but on the base of UML model can be generated code. UML uses generic set of graphic notations for creation an abstract model of the system called UML-model. The UML notation lets visually represent requirements, subsystems, structural and behavioral patterns, logical and physical elements, etc. UML defines 13 types of diagrams: Class (Package), Use Case, Sequence, Object, Collaboration, Component, Timing, Interaction Overview, State Machine, Composite Structure, Activity, and Deployment. All these types of UML Diagrams can be fast and easy created with powerful ConceptDraw DIAGRAM software extended with special Rapid UML solution from Software Development area of ConceptDraw Solution Park.

Data Modeling Diagram

The vector stencils library Activity diagrams from the solution Rapid UML contains specific data modeling symbols for ConceptDraw DIAGRAM diagramming and vector drawing software. The Rapid UML solution is contained in the Software Development area of ConceptDraw Solution Park.