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 DIAGRAM 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.

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.

UML Diagram Types List

Two types of diagrams are used in UML: Structure Diagrams and Behavior Diagrams. Behavior Diagrams represent the processes proceeding in a modeled environment. Structure Diagrams represent the elements that compose the system.

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).

Fully Connected Network Topology Diagram

Fully Connected Network Topology (Complete topology, Full mesh topology) is a network topology characterized by existence of direct links between all pairs of nodes. The Fully connected network including n nodes, contains n(n-1)/2 direct links. This topology is mostly used in military applications. It is a quite expensive network technology and is extremely impractical for the large networks. But when it is set, it provides a high degree of reliability thanks to the large quantity of redundant links between nodes and so multiplicity of paths for the data. The two-node network is also considered as a Fully connected network. Computer Network Diagrams solution from Computer and Networks area of ConceptDraw Solution Park offers the predesigned vector stencils libraries, examples and templates for easy designing various Computer network topology diagrams for wired and wireless networks, including the Fully connected topology. This solution is intended to help computer network designers and engineers perfectly illustrate network documentation, reports, presentations, etc.

Network diagrams with ConceptDraw DIAGRAM

Network diagram is effective tool for representing and description the network knots and connections between them in comprehensible graphic view, for studying and analysis them. The network administrators and engineers actively use Physical Network Diagrams and Logical Network Diagrams, which are both indispensable when developing and documenting new networks, and managing existing ones. Network diagrams let clearly represent the network configuration and structure, used protocols, addresses, and also names of network objects. Physical Network Diagrams depict the information about telecommunications data, servers, location of network equipment and number of network users. Logical Network Diagrams describe about logical network structure. It is useful to use the ready sets of network clipart, pictures and symbols for indication the network knots on a diagram, such as developed by professionals and offered in large quantity by Computer Network Diagrams solution from ConceptDraw Solution Park.

Point to Point Network Topology

This sample was created in ConceptDraw DIAGRAM diagramming and vector drawing software using the Computer and Networks solution from Computer and Networks area of ConceptDraw Solution Park. This sample shows the Point-to-point network topology. Network topology is the topological structure of the computer network. Point-to-point network topology is a simple topology that displays the network of exactly two hosts (computers, servers, switches or routers) connected with a cable. Point-to-point topology is widely used in the computer networking and computer architecture.

Computer Network. Computer and Network Examples

A Computer Network is a telecommunication network containing the set of nodes (computer network devices, such as computers, phones, servers) and allows them exchange the data using the network links. There are many kinds of computer networks. The primary difference is their size, according to the scale they can be classified as: Local area network (LAN), Metropolitan area network (MAN), Global Area Network (GAN), Wide area network (WAN), Storage area network (SAN), Campus area network (CAN), Personal area network (PAN). Computer networks also differ by connection method according to the used hardware technology (Ethernet, Wireless LAN, Optical fiber, HomePNA, Power line communication), by functional relationships that exist between network elements (Client-server, Active Networking, Peer-to-peer), by network topology (Tree computer network, Bus network, Star network, Ring network, Mesh network, etc.). Solutions of Computer and Networks Area from ConceptDraw Solution Park contain powerful drawing tools for easy designing diagrams for any Computer Network from listed diversity.