Entity–Relationship modeling was developed by Peter Chen in 1976 for database design. Usually ER Model is constructed as abstract data model which defines information structure and data.
The Entity-Relationship Diagram (ERD) is the world-known way to show the logical structure of databases in visual manner. It gives an overall plan of how the database will look and is constructed of graphical elements, mainly of rectangles (representing entities and their properties) and lines (representing relationships and relationships of entities with each other). All relationships are divided into three categories: one-to-one (1:1), one-to-many (1:N), and many-to-many (M:N). Each entity has properties or characteristics that are implemented in the form of attributes that describe each entity instance.
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.
Example 1. Entity-Relationship Diagram (ERD) - Students and Teachers
Entity-Relationship Diagram (ERD) solution includes vector icons advocated by popular Chen's or Crow's foot notations that can be used when describing an enterprise database. All they are offered by the libraries: ERD Chen's Notation and ERD Crow' Foot Notation.
Example 2. ERD Libraries
Develop ER models and ER diagrams using these predesigned vector objects, or start with one of predesigned ERD templates from the Entity-Relationship Diagram solution. Two professionally designed ERD templates (Chen and Crow's Foot) are available at ConceptDraw STORE.
Example 3. ConceptDraw STORE - ERD Templates
The vector graphic diagrams produced using the Entity-Relationship Diagram (ERD) solution and also samples included to it can be successfully used in whitepapers, presentations, datasheets, posters, or any technical materials.
Example 4. Entity-Relationship Diagram
The Entity-Relationship Diagram samples you see on this page were created in ConceptDraw DIAGRAM diagramming and vector drawing software using the Entity-Relationship Diagram (ERD) solution from ConceptDraw Solution Park. An experienced user spent 5 minutes creating each of these diagrams.
Use ConceptDraw DIAGRAM enhanced with Entity-Relationship Diagram (ERD) solution to draw quick and easy your own Entity-Relationship Diagram using Chen's or Crow's foot notations.
All source documents are vector graphic documents. They are available for reviewing, modifying, or converting to a variety of formats (PDF file, MS PowerPoint, MS Visio, and many other graphic formats) from the ConceptDraw STORE. The Entity-Relationship Diagram (ERD) Solution is available for all ConceptDraw DIAGRAM or later users.
NINE RELATED HOW TO's:
A database is a data collection, structured into some conceptual model. Two most common approaches of developing data models are UML diagrams and ER-model diagrams. There are several notations of entity-relationship diagram symbols and their meaning is slightly different. Crow’s Foot notation is quite descriptive and easy to understand, meanwhile, the Chen notation is great for conceptual modeling.
An entity relationship diagrams look very simple to a flowcharts. The main difference is the symbols provided by specific ERD notations. There are several models applied in entity-relationship diagrams: conceptual, logical and physical. Creating an entity relationship diagram requires using a specific notation. There are five main components of common ERD notations: Entities, Actions, Attributes, Cardinality and Connections. The two of notations most widely used for creating ERD are Chen notation and Crow foot notation. By the way, the Crow foot notation originates from the Chen notation - it is an adapted version of the Chen notation.
Picture: ERD Symbols and Meanings
Job duties in small companies are usually spread randomly among workers, causing lots of problems and misunderstanding. One of the ways to restore order in business processing is to create a cross-functional flowchart with swim lanes that would represent every step in production system. Another advantage of using swim lanes flowchart is that it represents not only processes, but people responsible for them.
Swim lane diagram is a kind of a process flow diagram. Its special feature is that it joins the features of process flow diagrams with organizational charts. Thus, a swim lane diagram display a participant of the business process in a conjunction with general flow of the business system. A swim lane diagram is looks similar to a swimming pool's lanes. Lanes can be horizontal and vertical. The lanes are pointed out relatively to resource name, which is assigned on implementation of the given part of the business process. ConceptDraw Business Process Mapping solution delivers the ability to design develop swim lanes flowcharts using the vector graphic objects of Swim Lanes library.
Picture: Swim Lane Diagrams
Network Security Architecture Diagram visually reflects the network's structure and construction, and all actions undertaken for ensuring the network security which can be executed with help of software resources and hardware devices. You dream to find powerful software for easy designing Network Security Architecture Diagram? We recommend to use ConceptDraw DIAGRAM extended with Network Security Diagrams Solution from the Computer and Networks Area of ConceptDraw Solution Park.
Picture: Network Security Architecture Diagram
It is very difficult to get into database model idea without any examples. To create one, you can use Chen’s notation for Entity Relationship Diagrams (ERD) and try to see all the peculiarities yourself. This notation describes entities and relations as basic geometric shapes like rectangles and diamonds.
Chen notation for Entity-relationship diagrams is used for designing relational databases. It depicts the database entities as a set of subjects. For example events, people, ideas, etc. All entities has common characteristics (attributes). Any object of the system is identified as the sole and unique. The name of entity should indicate the class or type of the the whole object, not a given example. The connection commonly represents a relationship between entities. Conceptdraw Entity-Relationship Diagrams (ERD) solution provides the libraries with ready-to-use ERD element fitting Chen's notation objects and relationships.
Picture: Design Element: Chen for Entity Relationship Diagram - ERD
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.
Picture: ER Diagram for Cloud Computing
An abstract representation is usually the first thing you will need while developing a database. To understand the ways that databases are structured, you should look through entity-relationship diagram examples and see the notations features and attributes. With an entity-relationship model you can describe a database of any complexity.
This Entity-relationship diagram is a tool for software developers. It enables every element of database to be managed, communicated and tested before release. This ERD was created using symbols advocated by Chen's notation. Because of a linguistic origin of the Chen’s notation, the boxes representing entities could be interpreted as nouns, and the relationships between them are in verb form, shown on a diagram as a diamond.
Picture: Entity Relationship Diagram Examples
ConceptDraw DIAGRAM is a world-class diagramming platform that lets you display, communicate, and present dynamically. It′s powerful enough to draw everything from basic flowcharts to complex engineering schematics.
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Picture: Business Process Mapping — How to Map a Work Process
Complexity of databases increases day by day, due to this the Entity relationship models and E-R diagrams become more and more popular, and now are an important part of database design. E-R diagrams created at ConceptDraw DIAGRAM allow visually and graphically represent structure and design of databases.
Picture: E-R Diagrams