Design Element: Chen
for Entity Relationship Diagram - ERD
Entity-relationship diagrams (ERDs) are intended for the development of data models and provide a standard method for determining data and relationships between them. The first notation for ERD was introduced by Chen and has been further developed by Barker.
Chen notation provides a rich set of data modeling tools, including essentially the ERD, as well as the attribute diagrams and decomposition charts. These diagram techniques are used primarily for designing relational databases.
The entity is a set of instances of real or abstract objects (people, events, conditions, ideas, items, etc.) that have common attributes or characteristics. Any system object can be represented by only one entity, that must to be uniquely identified. In this case the entity name must reflect the type or class of the object, not a specific instance. The relationship in the most general form represents a link between two or more entities.
In other words, the entities are the basic types of information stored in the database, and the relationships show how these types of data are interrelated with each other.
Entity-Relationship Diagram (ERD) solution from Software Development area of ConceptDraw Solution Park provides the libraries with predesigned set of ERD diagram design element Chen corresponding entities and relationships.
Example 1. Design Elements — Chen's (Mac OS X, Windows) for Entity Relationship Diagrams
As well as two libraries of vector stencils with entity relationship symbols, the Entity-Relationship Diagram (ERD) solution provides entity relationship diagram samples, examples, and templates. All they you can find at ConceptDraw STORE and use as the base for your own ER Diagrams.
Example 2. Entity-Relationship Diagrams - Chen Notation
The samples you see on this page were created in ConceptDraw DIAGRAM software using the Entity-Relationship Diagram (ERD) solution and show the ER Diagrams created with Chen notation. An experienced user spent 10 minutes creating these samples.
Use the Entity-Relationship Diagram (ERD) Solution for ConceptDraw DIAGRAM to create quick and easy your own ERDs using the Chen and Crow's Foot notations.
All source documents are vector graphic documents. They are available for reviewing, modifying, or converting to a variety of formats (PDF file, MS PowerPoint, MS Visio, and many other graphic formats) from the ConceptDraw STORE. The Entity-Relationship Diagram (ERD) Solution is available for all ConceptDraw DIAGRAM or later users.
TEN RELATED HOW TO's:
There are many ways to describe a database structure. One of the most usual is to draw an entity relationship diagram (ERD) using a Crow’s Foot notation to represent database elements. If you don’t want to draw it on paper, you should use an appropriate software.
An entity-relationship (ER) diagram is used to show the structure of a business database. ERD represents data as objects (entities) that are connected with standard relationships symbols which Illustrate an association between entities. ERD, there is a wide range of ERD notations used by data bases architects for reflecting the relationships between the data entities. According to the crow’s foot notation relationships are drawn as single labeled lines designating a certain kinds of relationship. Crow foot notation is a most frequently used ERD standard, because of improved readability of diagrams, with a more accurate use of space on the page.
Picture: Entity Relationship Diagram - ERD - Software for Design Crows Foot ER Diagrams
The world-best Entity Relationship Diagram software suitable for professional ERD drawing is ConceptDraw DIAGRAM software extended with the Entity-Relationship Diagram (ERD) solution. This solution contains all libraries, templates and samples you may need for professional ERD drawing.
Picture: Entity Relationship Diagram Software
ConceptDraw DIAGRAM diagramming and vector drawing software extended with Chemistry solution from the Science and Education area is a powerful chemistry drawing software that is ideal for quick and easy designing of various: chemistry drawings, scientific and educational chemistry illustrations, schemes and diagrams of chemical and biological lab set-ups, images with chemical formulas, molecular structures, chemical reaction schemes, schemes of labware,
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Picture: Chemistry Drawings
ConceptDraw DIAGRAM is a powerful diagramming and vector drawing software. Extended with Chemical and Process Engineering Solution from the Industrial Engineering Area of ConceptDraw Solution Park, it became the best Chemical Engineering software.
Picture: Chemical Engineering
This sample was created in ConceptDraw DIAGRAM diagramming and vector drawing software using the UML Class Diagram library of the Rapid UML Solution from the Software Development area of ConceptDraw Solution Park.
This sample describes the use of the classes, the generalization associations between them, the multiplicity of associations and constraints. Provided UML diagram is one of the examples set that are part of Rapid UML solution.
Picture: UML Class Diagram Generalization ExampleUML Diagrams
Electrical plan is a document that is developed during the first stage of the building design. This scheme is composed of conventional images or symbols of components that operate by means of electric energy. To simplify the creation of these schemes you can use house electrical plan software, which will not require a long additional training to understand how to use it. You only need to install the necessary software ant it’s libraries and you’ll have one less problem during the building projection.
Any building contains a number of electrical systems, including switches, fixtures, outlets and other lightening equipment. All these should be depicted in a building electrical plans and included to general building documentation. This home electrical plan displays electrical and telecommunication devices placed to a home floor plan. On the plan, each electrical device is referenced with the proper symbol. Electrical symbols are used for universal recognition of the building plan by different persons who will be working on the construction. Not all possible electric symbols used on a certain plan, so the symbols used in the current home plan are included to a legend. The electrical home plan may be added as a separate document to a complete set of building plans.
Picture: How To use House Electrical Plan Software
A wireframe is a scheme of a future web page. Wireframe illustrates the web page structure, location and size of the main elements, as well as their interaction with the user. With such scheme designer defines the functionality of the page, not its appearance.
Picture: Wireframe Tools
The first thing that usually comes to mind when talking about database models is ER-diagrams, and the ways to create them. The second most recognizable notation is the Crow’s Foot, which visually differs from Chen’s notation. Actually, it doesn’t matter which notation you’ll use for your entity relationship diagram (ERD), but the content is what matters.
When designing an Entity-Relationship Diagram one need to use a certain notated symbols that were developed and standardized especially for databases description. First of them - the Chen’s notation had a linguistic origin. It includes rectangle boxes to show entities that may be described as nouns, and the relationships between them described as verbs depicted in a form of diamond. Finally the Chen’s notation was simplified up to the Crow’s Foot notation. It represents a relationship as labeled line. It is precisely this notation is shown in the given figure. ConceptDraw DIAGRAM together with its Entity-Relationship Diagram (ERD) solution is designed to support professionals who deals with creating ER diagrams using the element of both - Chen’s and Crow's Foot notations.
Picture: Design Element: Crows Foot for Entity Relationship Diagram - ERD
The vector stencils library Chen ERD from the solution Entity-Relationship Diagrams (ERD) contains specific symbols of the Chen ERD notation including entity symbols and relationship symbols for ConceptDraw DIAGRAM diagramming and vector drawing software. The Entity-Relationship Diagrams (ERD) solution is contained in the Software Development area of ConceptDraw Solution Park.
Picture: Chen ERD Diagram
While designing a conceptual data model, you should use appropriate software. For instance, ConceptDraw DIAGRAM 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.
Picture: Entity Relationship Diagram Software Engineering