ER-model is a data model which lets describe the conceptual schemes in a specific subject area. It can help to highlight the key entities and specify relationships that can be established between these entities. During the database design, it is realized the transformation of ER model into certain database scheme based on the chosen data model (relational, object, network, etc.). There are used two notations for ERDs: Crow's Foot and Chen's.
Crow's Foot notation proposed by Gordon Everest represents the entity by rectangle containing its name (name must be unique within this model), and relation - by the line which links two entities involved in relationship. The relationship's plurality is graphically indicated by a "plug" on the end of the link, the optionality - by a circle. Entity-Relationship Diagrams based on Crow's Foot notation can be easily drawn using the ConceptDraw DIAGRAM. Extended with Entity-Relationship Diagram (ERD) solution, it is the best ERD diagrams software with powerful tools and ready design elements for Crow's Foot and Chen notations.
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.
When you need to visually represent the structure of relational database, Entity relationship diagram (ERD) is a type of diagram for that case.
Most entity-relationship diagrams can be built with objects from Flowchart solution or ERD Solution which contains inbuilt templates. Follow these steps to create your own custom ERD diagram.
Don't be frightened if it looks complex, ConceptDraw DIAGRAM makes it easy to create an ERD, and hundreds of other diagrams, in minutes.
Great part of modern approaches to the database design are based on the use of different versions of ER-models. The important feature of entity-relationship model is that it can be visually represented as a graphical diagram. ER-models and Entity Relationship Diagrams are so popular due to the simplicity and the presentation clarity. The conceptual basis led to their widespread use in CASE-systems, which support automatic design of relational databases. The typical concepts for ER-models are entity, relation and attribute. Relation is a graphically represented association between two entities, that establishes certain rules and all instances of the linked entity types are subject to these rules. In common ER-model this association is always binary. For representing entity-relationship elements, there are used Crow’s foot and Chen notations.
ConceptDraw DIAGRAM is a famous Entity Relationship Diagram software for Mac OSX which gives the ability to describe visually the databases with Chen’s and Crow’s Foot notation icons from Entity-Relationship Diagram (ERD) solution.
The vector stencils library Yourdon and Coad Notation from the solution OOAD contains specific symbols of the Yourdon and Coad notation such as data store symbol, data process symbol, loop symbol for ConceptDraw DIAGRAM diagramming and vector drawing software. The OOAD solution is contained in the Software Development area of ConceptDraw Solution Park.
An Entity Relationship (ER) Diagram is a type of flowchart that illustrates the logical structure of databases, how the different entities, such as people, objects or concepts relate to each other within a given system. How to draw ER Diagrams fast and easy? ConceptDraw DIAGRAM diagramming and vector drawing software enhanced with Entity-Relationship Diagram (ERD) solution from Software Development area of ConceptDraw Solution Park offers you the powerful abilities of designing the ER Diagrams and ERD drawings without efforts. This solution includes a lot of predesigned icons advocated by popular Chen's and Crow’s Foot notations, which can be used when describing an enterprise database and depicting it by abstract way. Simply drag the required objects to ConceptDraw document, connect them in a desired way and make style settings. But the easiest and fastest way of drawing ERDs is to make them on the base of ready-to-use Chen ERD and Crow's Foot ERD templates, which are both represented at ConceptDraw STORE.
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.
The ConceptDraw Flowchart component includes a set of samples and templates. This geathered as flowchart maker toolbox which focused on drawing flowcharts of any industry standards.
ConceptDraw DIAGRAM is a very easy-to-use and intuitive database design tool which can save you hundreds of work hours. See database diagram samples created with ConceptDraw DIAGRAM database modeling database diagram software.
This sample was created in ConceptDraw DIAGRAM diagramming and vector drawing software using the UML Use Case Diagram library of the Rapid UML Solution from the Software Development area of ConceptDraw Solution Park.
This sample shows the types of user’s interactions with the system and is used at the registration and working with the database system.
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