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ERD Symbols and Meanings

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.
How to Build an Entity Relationship Diagram (ERD)
How to Build an Entity Relationship Diagram (ERD)

Entity Relationship Diagram Symbols

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.

Entity-Relationship Diagram

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.

Entity Relationship Diagram Software Engineering

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.

Entity Relationship Diagram Software for Mac

Entity Relationship Diagram Software for Mac *
Great part of modern approaches to the database design are based on the use of different versions of ER-models. The important feature of entity-relationship model is that it can be visually represented as a graphical diagram. ER-models and Entity Relationship Diagrams are so popular due to the simplicity and the presentation clarity. The conceptual basis led to their widespread use in CASE-systems, which support automatic design of relational databases. The typical concepts for ER-models are entity, relation and attribute. Relation is a graphically represented association between two entities, that establishes certain rules and all instances of the linked entity types are subject to these rules. In common ER-model this association is always binary. For representing entity-relationship elements, there are used Crow’s foot and Chen notations. ConceptDraw DIAGRAM is a famous Entity Relationship Diagram software for Mac OSX which gives the ability to describe visually the databases with Chen’s and Crow’s Foot notation icons from Entity-Relationship Diagram (ERD) solution.

Design Element: Crows Foot for Entity Relationship Diagram - ERD

Design Element: Crows Foot <br>for Entity Relationship Diagram - ERD *
Entity-Relationship Diagram (ERD) is ideal tool that helps execute the detalization of data warehouse for a given designed system, lets to document the system's entities, attributes (objects' properties), and their interactions each other (relationships). Creation of an ERD requires the choice of specific set of notations, which the best suits for your database design. Two notations - Chen’s and Crow's Foot are applied for ERDs design. Chen's notation was developed first and has linguistic approach, the boxes represent the entities and are considered as nouns, relationships between them are shown as diamonds in a verb form. Over time Chen’s style was adapted into the popular standard - Crow’s Foot notation, where entities are shown as boxes and relationships - as labeled lines. ConceptDraw DIAGRAM software supplied with Entity-Relationship Diagram (ERD) solution offers samples and templates of ER diagrams, and also ready-to-use vector design elements - ERD Crow′s Foot and Chen's notation icons for easy designing your own ER diagrams for depicting databases.

Entity Relationship Diagram Examples

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.
How to Build an Entity Relationship Diagram (ERD)
How to Build an Entity Relationship Diagram (ERD)

Components of ER Diagram

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).

ER Diagram for Cloud Computing

ER Diagram for Cloud Computing *
The entity–relationship (ER) model is a data model that lets graphically represent the information system and depict the relationships between people, objects, concepts, places, and events within a given system. It is also convenient to use the ER Diagram for Cloud computing representation and description the Cloud computing architecture, design them with pleasure using the extensive tools of the Cloud Computing Diagrams solution from the Computers and Network area of ConceptDraw Solution Park.
The vector stencils library "UML class diagrams" contains 38 symbols for the ConceptDraw PRO diagramming and vector drawing software.
"... classes are represented with boxes which contain three parts:
(1) The top part contains the name of the class. It is printed in Bold, centered and the first letter capitalized.
(2) The middle part contains the attributes of the class. They are left aligned and the first letter is lower case.
(3) The bottom part gives the methods or operations the class can take or undertake. They are also left aligned and the first letter is lower case. ...
To indicate a classifier scope for a member, its name must be underlined. ...
An association can be named, and the ends of an association can be adorned with role names, ownership indicators, multiplicity, visibility, and other properties. ...
Aggregation ... is graphically represented as a hollow diamond shape on the containing class end of the tree with a single line that connects the contained class to the containing class.
... graphical representation of a composition relationship is a filled diamond shape on the containing class end of the tree of lines that connect contained class(es) to the containing class.
... graphical representation of a Generalization is a hollow triangle shape on the superclass end of the line (or tree of lines) that connects it to one or more subtypes.
... graphical representation of a Realization is a hollow triangle shape on the interface end of the dashed line (or tree of lines) that connects it to one or more implementers. A plain arrow head is used on the interface end of the dashed line that connects it to its users.
Multiplicity ... representation of an association is a line with an optional arrowhead indicating the role of the object(s) in the relationship, and an optional notation at each end indicating the multiplicity of instances of that entity (the number of objects that participate in the association).
Entity classes ... are drawn as circles with a short line attached to the bottom of the circle. Alternatively, they can be drawn as normal classes with the «entity» stereotype notation above the class name." [Class diagram. Wikipedia]
The example "Design elements - UML class diagrams" is included in the Rapid UML solution from the Software Development area of ConceptDraw Solution Park.
UML class diagram symbols
UML class diagram symbols, template class, self association, package, object, note, interface, frame, component, class, NARY, N-ary association,
Used Solutions
"Crow's Foot notation is used in Barker's Notation, SSADM and Information Engineering. Crow's Foot diagrams represent entities as boxes, and relationships as lines between the boxes. Different shapes at the ends of these lines represent the cardinality of the relationship." [Entity–relationship model. Wikipedia]
The vector stencils library ERD, crow's foot notation contains 18 symbols for creating the ER-diagrams using the ConceptDraw PRO diagramming nd vector drawing software.
The example"Design elements - ERD solution (crow's foot notation)" is included in the Entity-Relationship Diagram (ERD) solution from the Software Development area of ConceptDraw Solution Park.
Crow's foot ERD
Crow's foot ERD, entity,
Used Solutions