Entity-Relationship Diagram (ERD)

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.

Developing Entity Relationship Diagrams

When you need to visually represent the structure of relational database, Entity relationship diagram (ERD) is a type of diagram for that case. Most entity-relationship diagrams can be built with objects from Flowchart solution or ERD Solution which contains inbuilt templates. Follow these steps to create your own custom ERD diagram. Don't be frightened if it looks complex, ConceptDraw DIAGRAM makes it easy to create an ERD, and hundreds of other diagrams, in minutes.

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.

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.

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Entity-Relationship Diagram (ERD) with ConceptDraw DIAGRAM

Entity-Relationship Diagram (ERD) is applied for detailed description of structures and high-level (conceptual) design databases using the Chen's and Crow's Foot notations. An ERD represents a diagram constructed mainly of rectangular blocks (for entities, data) linked with relationships. The links between the blocks are used to describe relations between the entities. There are three types of relationships: one-to-one, one-to-many, and many-to-many. Use the specialized ERD software - ConceptDraw DIAGRAM to create the Entity-Relationship Diagrams (ERDs) of any degree of complexity with Chen's and Crow's Foot notations. Draw them easily applying the powerful built-in tools and libraries of predesigned ERD vector objects from Entity-Relationship Diagram (ERD) solution from the Software Development area of ConceptDraw Solution Park. You can also start with one of ready template or sample included to this solution. Designing the ERDs in ConceptDraw DIAGRAM you can easy move the objects within a diagram with saving the relationships between them.

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: Chen for Entity Relationship Diagram - ERD

Entity-Relationship Diagrams (ERDs) were developed and introduced as a convenient and visual tool for the data modeling, they are the perfect way for easy determining data and also relationships between them. The first standard notation for ERD was proposed by Chen. Chen's notation is very rich on the data modeling tools and standard notation symbols and elements for drawing easy understandable Entity-relationship diagrams, Attribute diagrams, Decomposition charts, which are especially popular for designing relational databases. The entity is the main term, it is a set of instances abstract or real objects with common characteristics or attributes. Any system's object is represented by one uniquely identified entity, relationships describe the links between the entities. ConceptDraw DIAGRAM diagramming software, which includes the Entity-Relationship Diagram (ERD) solution, offers all needed tools for professional drawing ER diagrams. Specially developed vector ERD design elements according to Chen and Crow's Foot notations are indispensible for professional ERDs design.