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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 PRO 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.
How to Build an Entity Relationship Diagram (ERD)
How to Build an Entity Relationship Diagram (ERD)
"Chen's notation for entity–relationship modeling uses rectangles to represent entity sets, and diamonds to represent relationships appropriate for first-class objects: they can have attributes and relationships of their own. If an entity set participates in a relationship set, they are connected with a line.
Attributes are drawn as ovals and are connected with a line to exactly one entity or relationship set.
Cardinality constraints are expressed as follows:
- a double line indicates a participation constraint, totality or surjectivity: all entities in the entity set must participate in at least one relationship in the relationship set;
- an arrow from entity set to relationship set indicates a key constraint, i.e. injectivity: each entity of the entity set can participate in at most one relationship in the relationship set;
- a thick line indicates both, i.e. bijectivity: each entity in the entity set is involved in exactly one relationship.
- an underlined name of an attribute indicates that it is a key: two different entities or relationships with this attribute always have different values for this attribute.
Attributes are often omitted as they can clutter up a diagram; other diagram techniques often list entity attributes within the rectangles drawn for entity sets." [Entity–relationship model. Wikipedia]
The vector stencils library ERD, Chen's notation contains 13 symbols for drawing entity-relatinship diagrams using the ConceptDraw PRO diagramming and vector drawing software.
The example "Design elements - ER diagram (Chen notation)" is included in the Entity-Relationship Diagram (ERD) solution from the Software Development area of ConceptDraw Solution Park.
Chen's ERD
Chen's ERD, week key attribute, weak entity, relationship, multivalue attribute, key attribute, identifying relationship, entity, derived attribute, attribute, associative entity,
"Chen's notation for entity–relationship modeling uses rectangles to represent entity sets, and diamonds to represent relationships appropriate for first-class objects: they can have attributes and relationships of their own. If an entity set participates in a relationship set, they are connected with a line.
Attributes are drawn as ovals and are connected with a line to exactly one entity or relationship set.
Cardinality constraints are expressed as follows:
- a double line indicates a participation constraint, totality or surjectivity: all entities in the entity set must participate in at least one relationship in the relationship set;
- an arrow from entity set to relationship set indicates a key constraint, i.e. injectivity: each entity of the entity set can participate in at most one relationship in the relationship set;
- a thick line indicates both, i.e. bijectivity: each entity in the entity set is involved in exactly one relationship.
- an underlined name of an attribute indicates that it is a key: two different entities or relationships with this attribute always have different values for this attribute.
Attributes are often omitted as they can clutter up a diagram; other diagram techniques often list entity attributes within the rectangles drawn for entity sets." [Entity–relationship model. Wikipedia]
The vector stencils library ERD, Chen's notation contains 13 symbols for drawing entity-relatinship diagrams using the ConceptDraw PRO diagramming and vector drawing software.
The example "Design elements - ER diagram (Chen notation)" is included in the Entity-Relationship Diagram (ERD) solution from the Software Development area of ConceptDraw Solution Park.
Chen's ERD
Chen's ERD, week key attribute, weak entity, relationship, multivalue attribute, key attribute, identifying relationship, entity, derived attribute, attribute, associative entity,
"In software engineering, an entity–relationship model (ER model) is a data model for describing a database in an abstract way.Chen's notation for entity–relationship modeling uses rectangles to represent entity sets, and diamonds to represent relationships appropriate for first-class objects: they can have attributes and relationships of their own. If an entity set participates in a relationship set, they are connected with a line.
Attributes are drawn as ovals and are connected with a line to exactly one entity or relationship set." [Entity–relationship model. Wikipedia]
This sample Chen's ER-diagram illustrates the structure of a typical MMORP game.
"Massively multiplayer online role-playing game (MMORPG) mixes the genres of role-playing video games and Massively multiplayer online games, possibly in the form of web browser-based games, in which a very large number of players interact with one another within a virtual world.
As in all RPGs, players assume the role of a character (often in a fantasy world or science-fiction world) and take control over many of that character's actions. MMORPGs are distinguished from single-player or small multi-player online RPGs by the number of players, and by the game's persistent world (usually hosted by the game's publisher), which continues to exist and evolve while the player is offline and away from the game." [Massively multiplayer online role-playing game. Wikipedia]
This ERD example was redrawn using the ConceptDraw PRO diagramming and vector drawing software from the Wikipedia file: ER Diagram MMORPG.png. [en.wikipedia.org/ wiki/ File:ER_ Diagram_ MMORPG.png]
This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. [creativecommons.org/ licenses/ by-sa/ 3.0/ deed.en]
This Chen's ERD example is included in the Entity-Relationship Diagram (ERD) solution from the Software Development area of ConceptDraw Solution Park.
Chen's ERD
Chen's ERD, weak key attribute, weak entity, relationship, multivalue attribute, key attribute, identifying relationship, entity, derived attribute, attribute,
"An ER model is an abstract way of describing a database. In the case of a relational database, which stores data in tables, some of the data in these tables point to data in other tables - for instance, your entry in the database could point to several entries for each of the phone numbers that are yours. The ER model would say that you are an entity, and each phone number is an entity, and the relationship between you and the phone numbers is 'has a phone number'. Diagrams created to design these entities and relationships are called entity–relationship diagrams or ER diagrams.
Using the three schema approach to software engineering, there are three levels of ER models that may be developed. ...
Conceptual data model ... is the highest level ER model in that it contains the least granular detail but establishes the overall scope of what is to be included within the model set.
Logical ER model ... contains more detail than the conceptual ER model. In addition to master data entities, operational and transactional data entities are now defined.
The physical ER model is normally developed to be instantiated as a database. Therefore, each physical ER model must contain enough detail to produce a database and each physical ER model is technology dependent since each database management system is somewhat different.
Physical model ... is normally forward engineered to instantiate the structural metadata into a database management system as relational database objects such as database tables, database indexes such as unique key indexes, and database constraints such as a foreign key constraint or a commonality constraint." [Entity–relationship model. Wikipedia]
This crow's foot entity-relationship diagram (ERD) example "Educational data base" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Entity-Relationship Diagram (ERD) solution from the Software Development area of ConceptDraw Solution Park.
ERD
ERD, entity,

Process Flowchart

The main reason of using Process Flowchart or PFD is to show relations between major parts of the system. Process Flowcharts are used in process engineering and chemical industry where there is a requirement of depicting relationships between major components only and not include minor parts. Process Flowcharts for single unit or multiple units differ in their structure and implementation. ConceptDraw PRO is Professional business process mapping software for making Process flowcharts, Process flow diagram, Workflow diagram, flowcharts and technical illustrations for business documents and also comprehensive visio for mac application. Easier define and document basic work and data flows, financial, production and quality management processes to increase efficiency of your business with ConcepDraw PRO. Business process mapping software with Flowchart Maker ConceptDraw PRO includes extensive drawing tools, rich examples and templates, process flowchart symbols and shape libraries, smart connectors that allow you create the flowcharts of complex processes, process flow diagrams, procedures and information exchange. Process Flowchart Solution is project management workflow tools which is part ConceptDraw Project marketing project management software. Drawing charts, diagrams, and network layouts has long been the monopoly of Microsoft Visio, making Mac users to struggle when needing such visio alternative like visio for mac, it requires only to view features, make a minor edit to, or print a diagram or chart. Thankfully to MS Visio alternative like ConceptDraw PRO software, this is cross-platform charting and business process management tool, now visio alternative for making sort of visio diagram is not a problem anymore however many people still name it business process visio tools.
How To Create a Process Flow Chart (business process modelling techniques)
How To Create a Process Flow Chart (business process modelling techniques)
The vector stencils library "ERD, Chen's notation" contains 13 ERD elements.
Use it for drawing ER-diagrams using Chen's notation in the ConceptDraw PRO diagramming and vector drawing software extended with the Entity-Relationship Diagram (ERD) solution from the Software Development area of ConceptDraw Solution Park.
Entity
Entity, entity,
Weak entity
Weak entity, weak entity,
Relationship
Relationship, relationship,
Identifying Relationship
Identifying Relationship, identifying relationship,
Associative Entity
Associative Entity, associative entity,
Participation
Participation,
Optional participation
Optional participation,
Recursive Relationship
Recursive Relationship,
Attribute
Attribute, attribute,
Key attribute
Key attribute, key attribute,
Weak key attribute
Weak key attribute, weak key attribute,
Derived attribute
Derived attribute, derived attribute,
Multivalue attribute
Multivalue attribute, multivalue attribute,

football, american football, football field, american football field, football field dimensions, offense, defense, football plays, football diagram Football

football, american football, football field, american football field, football field dimensions, offense, defense, football plays, football diagram
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Databases Access Objects Model with ConceptDraw PRO

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