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 allow visually and graphically represent structure and design of databases.
You can use so popular Chen's notation to represent all components of database and their relationships on the ER diagram. This notation was developed and implemented by Peter Chen in 1976. The main components of the E-R diagrams are:
- attributes that describe these entities,
- relationships among these entities that describe associations between the data,
- cardinalities that describe the number of relationship participants: one-to-many (1:M), many-to-many (M:N), and one-to-one (1:1).
In a Chen's notation, entities are represented by rectangles on the diagram with the entity names written inside and relationships are represented by diamonds. Another popular type of E-R diagrams is known as Crow's Foot notation that is derived from the Chen's notation.
Example 1. E-R Diagram - Students and teachers
Use of ConceptDraw DIAGRAM for professional ERD drawing includes using the predesigned components of ER diagram, such as entity relationship symbols, work flow shapes, entity relationship stencils. All they are provided for easy use by 2 libraries of Entity-Relationship Diagram (ERD) Solution from the Software Development Area for ConceptDraw Solution Park.
Example 2. ERD Libraries
There is also wide collection of predesigned E-R Diagrams which is represented at ConceptDraw STORE. All E-R Diagrams samples and templates are well thought-out, professionally designed, can be easy changed according to your needs and further successfully used.
Example 3. E-R Diagrams in ConceptDraw DIAGRAM
The following features make ConceptDraw DIAGRAM extended with the Entity-Relationship Diagram (ERD) solution the most effective E-R diagrams design software:
- You don't need to be an artist to draw professional looking diagrams in a few minutes.
- Large quantity of ready-to-use vector objects makes drawing your diagrams quick and easy.
- Extensive collection of pre-designed templates and samples give you a great start for your own diagrams.
- ConceptDraw DIAGRAM provides you with the possibility to use the grid, rules and guides. You can easily rotate, group, align, and arrange objects, and use different fonts and colors to make your diagram stand out.
- All ConceptDraw DIAGRAM documents are vector graphic files and are available for reviewing, modifying, and converting to a variety of formats: image, HTML, PDF file, MS PowerPoint Presentation, Adobe Flash, MS Visio.
- Using ConceptDraw STORE you can navigate through ConceptDraw Solution Park, managing downloads and updates. You can access libraries, templates and samples directly from ConceptDraw STORE.
- If you have any questions, our support is free of charge and always ready to come to your aid.
NINE RELATED HOW TO's:
Both Crow’s Foot and Chen’s notations are used to build database models. Each of them has its’ own features, and if you use a proper entity relationship diagram software, you’ll be able to create diagrams of any notation. Database model with clearly defined entities and relationships between them facilitates further work greatly.
This ERD represents the model of Employee Certification Entity. The entity-relationship diagram is a visual instrument of database software development. It is used to structure data and to define the relationships between structured data groups. This ERD was designed with a help of ConceptDraw Entity-Relationship Diagram (ERD) solution. The solution supports the both basic ERD notations used to describe the structure of database: Chen's and Crow’s Foot notations.
Picture: Entity Relationship Software
A list of parameters on which networks differ is very long. A large network with a range up to 50 kilometers is called metropolitan area network (MAN), and this type of network can include several local area networks. Metropolitan networks in their turn connect into global area networks.
Here you will see a Metropolitan Area Network (MAN). This is an extensive network which occupies a large territory including a few buildings or even the whole city. The space of the MAN is bigger than LAN, but lower than WAN. MAN comprise a lot of communication equipment and delivers the Internet connection to the LANs in the city area. Computer and Networks solution for ConceptDraw DIAGRAM provides a set of libraries with ready-to-use vector objects to design various kinds of computer networks.
Picture: Metropolitan area networks (MAN). Computer and Network Examples
The ConceptDraw vector stencils library Cisco Telepresence contains videoconference equipment symbols for drawing the computer network diagrams.
Picture: Cisco Telepresence. Cisco icons, shapes, stencils and symbols
This sample was created in ConceptDraw DIAGRAM diagramming and vector drawing software using the Business Process Diagram Solution from the Business Processes area of ConceptDraw Solution Park. The Business Process Solution is based on the standard BPMN 2.0 and includes the set of libraries of ready-to-use objects.
Picture: BPR Diagram. Business Process Reengineering Example
UML Timing Diagram as special form of a sequence diagram are used to explore the behaviors of objects throughout a given period of time.
ConceptDraw has 393 vector stencils in the 13 libraries that helps you to start using software for designing your own UML Diagrams. You can use the appropriate stencils of UML notation from UML Timing library.
Picture: UML Timing Diagram, Design Elements
There are many ways to define the flow of information within a system. Structured-systems analysis method often uses data flow diagrams to show data flow, data storages and data processing visualization. These diagrams are easy to develop and quite useful.
Here is a dataflow diagram presenting an example of the manufacturing process flow. The oval process shapes represent a process that controls data within the current system. The process may produce data or make some action based on data. Data flows are represented by lines. They show the movement of information through the system. The direction of the data flow is depicted by the arrow. The external entities are shown by rectangles. They represent the external entities interacting with the system. The data store objects (unclosed rectangles) are used to show data bases participating in a process flow.
Picture: Data Flow Diagram