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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 PRO software. Read more

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 PRO 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. Read more
How to Build an Entity Relationship Diagram (ERD)
How to Build an Entity Relationship Diagram (ERD)

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 PRO 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). Read more

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 PRO. 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. Read more
How to Build an Entity Relationship Diagram (ERD)
How to Build an Entity Relationship Diagram (ERD)

Data Modeling with Entity Relationship Diagram

Data modeling is actively applied in analysis and uses wide set of methods for description the data requirements in a system. One of the most popular and well-known is the ERD method of database modeling. The best ERD tool for the Mac and Windows is ConceptDraw PRO software extended with the Entity-Relationship Diagram (ERD) solution from the Software Development Area for ConceptDraw Solution Park, which is sharpened for professional ERD drawing and data modeling with Entity Relationship Diagram. Read more

ConceptDraw PRO 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 PRO with Entity-Relationship Diagram (ERD) solution from ConceptDraw Solution Park is helpful for easy creation Entity-Relationship Diagrams. Read more

Electrical Symbols — Maintenance

Electrical maintenance - troubleshooting electrical circuit. The diagrams are a big help when workers try to find out why a circuit does not work correctly. 26 libraries of the Electrical Engineering Solution of ConceptDraw PRO make your electrical diagramming simple, efficient, and effective. You can simply and quickly drop the ready-to-use objects from libraries into your document to create the electrical diagram. Read more

Mechanical Drawing Symbols

Mechanical Drawings are the special type of technical diagrams that visualize the structure of complex systems and illustrate the information about ventilation, heating, air conditioning, i.e. HVAC systems. These drawings are created on the base of floor plans and reflected ceiling plans, and then become an obligatory part of construction project which is needed directly for construction a building and for receiving a permit on it. Mechanical drawings and diagrams help effectively represent construction, technical and engineering solutions, and also schematics of different mechanical equipment. ConceptDraw PRO vector drawing software enhanced with Mechanical Engineering solution from Engineering area of ConceptDraw Solution Park provides wide set of effective drawing tools, predesigned mechanical drawing symbols, templates, samples and examples. Use of standardized and recognized mechanical vector symbols helps you design understandable mechanical drawings, diagrams and mechanical engineering schematics. Read more

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. Read more

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. Read more