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.

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.

Entity Relationship Diagram - ERD - Software for Design Crows Foot ER Diagrams

ER-model is a data model which lets describe the conceptual schemes in a specific subject area. It can help to highlight the key entities and specify relationships that can be established between these entities. During the database design, it is realized the transformation of ER model into certain database scheme based on the chosen data model (relational, object, network, etc.). There are used two notations for ERDs: Crow's Foot and Chen's. Crow's Foot notation proposed by Gordon Everest represents the entity by rectangle containing its name (name must be unique within this model), and relation - by the line which links two entities involved in relationship. The relationship's plurality is graphically indicated by a "plug" on the end of the link, the optionality - by a circle. Entity-Relationship Diagrams based on Crow's Foot notation can be easily drawn using the ConceptDraw DIAGRAM. Extended with Entity-Relationship Diagram (ERD) solution, it is the best ERD diagrams software with powerful tools and ready design elements for Crow's Foot and Chen notations.

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.

UML Class Diagram Notation

When it comes to system construction, a class diagram is the most widely used diagram. UML Class Diagrams is a type of static structure diagram that is used for general conceptual modeling of the systematics of the application. Such a diagram would illustrate the object-oriented view of a system. The object orientation of a system is indicated by a class diagram. It describes the structure of a system by showing the general issues,classes of a system, attributes, operations, interfaces, inheritance, and the relationships between them.

JSD - Jackson system development

Jackson System Development (JSD) is a linear method of system development created by Michael A. Jackson and John Cameron in the 1980s. It comprises the whole software life cycle directly or providing a framework for more specialized techniques. When implementing the Jackson System Development method and designing JSD diagrams, you can succesfully use the powerful and helpful tools of ConceptDraw DIAGRAM software extended with Entity-Relationship Diagram (ERD) solution from the Software Development area of ConceptDraw Solution Park.