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Entity Relationship Diagram Symbols

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 PRO software. Read more

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. Read more
"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. Read more
Chen's ERD
Chen's ERD, week key attribute, weak entity, relationship, multivalue attribute, key attribute, identifying relationship, entity, derived attribute, attribute, associative entity,

ConceptDraw PRO ER Diagram Tool

Entity-relationship model, also called ER-model, is the main tool of domain modeling on the stage of conceptual design. The modeling of domain data structures is based on the use of graphical tools - Entity-Relationship diagrams (ER-diagrams). The core concepts of ER-Diagram are entity, attribute and relationship. ER-diagram lets visually represent the entities, helps effectively document all properties of designed system and to detail the data storages. To represent the elements at ER-model are commonly used Chen’s notation and Crow’s foot notation, each has its pros and cons. The entity on ER-diagram is represented in the form of rectangle, which specifies its name. An attribute is a property of the entity and relationship is an interaction between the entities. The relationship between two entities is called binary, between more than two entities - ternary. Specific software, such as ConceptDraw PRO with Entity-Relationship Diagram (ERD) solution from ConceptDraw Solution Park is helpful for easy creation Entity-Relationship Diagrams. Read more

Martin ERD Diagram

The vector stencils library Crow's Foot Notation from the solution Entity-Relationship Diagrams (ERD) contains specific symbols of the Crow's foot notation such as relationship symbols and entity symbols for ConceptDraw PRO diagramming and vector drawing software. The Entity-Relationship Diagrams (ERD) solution is contained in the Software Development area of ConceptDraw Solution Park. Read more

Data modeling with ConceptDraw PRO

Data modelling will help you to study and analyze business processes in your organization for optimization and increase of effectiveness and production. Read more

Entity-Relationship Diagram (ERD) with ConceptDraw PRO

Entity-Relationship Diagram (ERD) is applied for detailed description of structures and high-level (conceptual) design databases using the Chen's and Crow's Foot notations. An ERD represents a diagram constructed mainly of rectangular blocks (for entities, data) linked with relationships. The links between the blocks are used to describe relations between the entities. There are three types of relationships: one-to-one, one-to-many, and many-to-many. Use the specialized ERD software - ConceptDraw PRO to create the Entity-Relationship Diagrams (ERDs) of any degree of complexity with Chen's and Crow's Foot notations. Draw them easily applying the powerful built-in tools and libraries of predesigned ERD vector objects from Entity-Relationship Diagram (ERD) solution from the Software Development area of ConceptDraw Solution Park. You can also start with one of ready template or sample included to this solution. Designing the ERDs in ConceptDraw PRO you can easy move the objects within a diagram with saving the relationships between them. Read more
"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. Read more
Chen's ERD
Chen's ERD, weak key attribute, weak entity, relationship, multivalue attribute, key attribute, identifying relationship, entity, derived attribute, attribute,
The vector stencils library "AWS Database" contains 30 Amazon Web Services database icons: Amazon DynamoDB symbols, Amazon Relational Database Service symbols, Amazon ElasticCache symbols, Amazon SimpleDB symbols, Amazon Redshift symbols.
Use it to draw AWS architecture diagrams of your cloud service.
The symbols example "AWS Database - Vector stencils library" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the AWS Architecture Diagrams solution from the Computer and Networks area of ConceptDraw Solution Park. Read more
DynamoDB
DynamoDB, DynamoDB,
Table
Table, table,
Item
Item, item,
Items
Items, items,
Attribute
Attribute, attribute,
Attributes
Attributes, attributes,
Global secondary index
Global secondary index, global secondary index,
Amazon RDS
Amazon RDS, Amazon RDS,
RDS DB instance
RDS DB instance, RDS DB instance,
RDS DB instance standby (Multi-AZ)
RDS DB instance standby (Multi-AZ), RDS DB instance standby, Multi-AZ,
RDS DB instance read replica
RDS DB instance read replica, RDS DB instance read replica,
MySQL DB instance
MySQL DB instance, MySQL DB instance,
Oracle DB instance
Oracle DB instance, Oracle DB instance,
MS SQL instance
MS SQL
 instance, MS SQL instance,
PostgreSQL instance
PostgreSQL instance, PostgreSQL instance,
SQL master
SQL master, SQL master,
SQL slave
SQL slave, SQL slave,
PIOP
PIOP, PIOP,
ElastiCache
ElastiCache, ElastiCache,
Cache node
Cache node, cache node,
Redis
Redis, Redis,
Memcached
Memcached, Memcached,
Amazon SimpleDB
Amazon SimpleDB, Amazon SimpleDB,
Domain
Domain, domain,
Amazon Redshift
Amazon Redshift, Amazon Redshift,
Solid state disks
Solid state disks, solid state disks,
DW2 Dense Compute
DW2 Dense Compute, DW2 Dense Compute,
DW1 Dense Compute
DW1 Dense Compute, DW1 Dense Compute,

Entity Relationship Diagram - ERD - Software for Design Chen ER Diagrams

The Entity-Relationship Diagram (ERD) solution from ConceptDraw Solution Park extends ConceptDraw PRO vector graphics and diagramming software with the ability to describe a database using the Entity-Relationship (Chen) model. Use it for design your ERDs and verify that ConceptDraw PRO offers the best ERD diagrams software tools for design element Chen notation. Read more