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).

Booch OOD Diagram

The vector stencils library Booch OOD from the solution Software Engineering contains specific symbols of the Booch method such as class symbols, association symbols, aggregation symbols for ConceptDraw DIAGRAM diagramming and vector drawing software. The Software Engineering solution is contained in the Software Development area of ConceptDraw Solution Park.

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.

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.

Program Evaluation and Review Technique (PERT) with ConceptDraw DIAGRAM

Program Evaluation and Review Technique (abbr. PERT) is a method developed by Ministry of Defense of the USA in 1958 for the project of creation the missile system Polaris. PERT diagram is one of the tools for project management that lets greatly simplify the planning and scheduling of large and complex projects. PERT diagram provides evaluation of project run-time and labor forces, it helps to analyze the time necessary for execution each of project tasks and the whole project, and to calculate the project critical path. PERT chart depicts the set of tasks connected each other in order of their execution and is constructed according to one of definite rules - AOA (activity on arrow) or AON (activity on node). It doesn't give you ready concrete decisions, but helps to find them. Design easy the PERT diagrams in ConceptDraw DIAGRAM software enhanced with Seven Management and Planning Tools solution from Management area of ConceptDraw Solution Park. You have a possibility to build the PERT chart of any type, but AON variant is easier for building and perception.

Metropolitan area networks (MAN). Computer and Network Examples

A Metropolitan Area Network (MAN) is a great computer network located on the large geographical area or region. It is a network bigger than Local Area Network (LAN), but territorially smaller than Wide Area Network (WAN), its diameter usually ranges from 5 to 50 kilometers. MAN usually includes several buildings or even the whole city (metropolis). It is based on high data rate compounds using the fiber channels and other digital data transmission channels. MAN includes a lot of communicating devices, for its construction are used multiple routers, switches and hubs. MAN can combine together several Local Area Networks or Campus Area Networks located in different buildings within a city and provides the Internet connectivity for them. Solutions included to Computer and Networks Area for ConceptDraw Solution Park are the real godsend for those who want design Computer Network Diagrams, and among others the Metropolitan Area Network Diagrams. They offer the libraries with ready-to-use vector design elements, professional-looking examples, samples and templates.