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.

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.

Data Flow Diagrams

The information system manages the flow of data introduced into the system. To graphically represent and document the flow of data through some information system is used a Data Flow Diagram (DFD). DFD is a way to visualize the flow of data or data processing, to clearly demonstrate what type of data or information is transferred, where they come from and where are sent. It lets to create an overview of the system, to depict the major steps, and effectively model the processes. DFDs are helpful for analyzing and modifying the business systems. Traditionally are used two notations for DFDs creation - Yourdon-Coad and Gane-Sarson. ConceptDraw DIAGRAM software offers a special Data Flow Diagrams solution from Software Development area, which enables to quickly and simply create professional Data Flow Diagrams including the data storage, data flows, external entities, functional transforms, control transforms and signals. Use the offered templates, samples and extensive range of libraries to design your own Data Flow Diagrams in minutes.

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.

Example of DFD for Online Store (Data Flow Diagram)

Data Flow Diagram (DFD) is a methodology of graphical structural analysis and information systems design, which describes the sources external in respect to the system, recipients of data, logical functions, data flows and data stores that are accessed. DFDs allow to identify relationships between various system's components and are effectively used in business analysis and information systems analysis. They are useful for system’s high-level details modeling, to show how the input data are transformed to output results via the sequence of functional transformations. For description of DFD diagrams are uses two notations — Yourdon and Gane-Sarson, which differ in syntax. Online Store DFD example illustrates the Data Flow Diagram for online store, the interactions between Customers, Visitors, Sellers, depicts User databases and the flows of Website Information. ConceptDraw DIAGRAM enhanced with Data Flow Diagrams solution lets you to draw clear and simple example of DFD for Online Store using special libraries of predesigned DFD symbols.

ER Diagram Tool

Creating of Entity-Relationship Diagrams (ERDs) is a complex process that requires convenient, automated tools. ConceptDraw DIAGRAM diagramming and vector drawing software offers a powerful ER Diagram Tool - the Entity-Relationship Diagram (ERD) Solution from the Software Development Area.

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.

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 DIAGRAM 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.

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).