What does ER diagram mean?
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entity relationship diagram
An entity relationship diagram (ERD), also known as an entity relationship model, is a graphical representation that depicts relationships among people, objects, places, concepts or events within an information technology (IT) system.
What is the function of ER diagram?
An Entity Relationship (ER) Diagram is a type of flowchart that illustrates how “entities” such as people, objects or concepts relate to each other within a system.
What is logical relational data model?
A logical relational data model defines what an organization knows about things of interest to the business and graphically shows how they relate to each other in an entity relationship (ER) diagram. An entity relationship diagram is an abstract conceptual representation of structured data.
What is IE notation?
The most recognizable characteristic of crow’s foot notation (also known as IE notation) is that it uses graphical symbols to indicate the ‘many’ side of the relationship. The three-pronged ‘many’ symbol is also how this widely-used notation style got its name.
What are the ER diagram symbols and their meaning?
Rectangles: This Entity Relationship Diagram symbol represents entity types. Ellipses : Symbol represent attributes. Diamonds: This symbol represents relationship types. Lines: It links attributes to entity types and entity types with other relationship types.
What is dotted line in ER diagram?
A dashed line means that the relationship is strong, whereas a solid line means that the relationship is weak.
What is crow’s foot model?
Crow’s foot diagrams represent entities as boxes, and relationships as lines between the boxes. Different shapes at the ends of these lines represent the relative cardinality of the relationship. These symbols are used in pairs to represent the four types of cardinality that an entity may have in a relationship.
What is ER diagram and how to create an ERD?
What is ER Diagram? ER Diagram stands for Entity Relationship Diagram, also known as ERD is a diagram that displays the relationship of entity sets stored in a database. In other words, ER diagrams help to explain the logical structure of databases. ER diagrams are created based on three basic concepts: entities, attributes and relationships.
What is an Entity Relationship (ER diagram)?
An Entity Relationship (ER Diagram is a type of flowchart that illustrates how “entities” such as people, objects or concepts relate to each other within a system. ER Diagrams are most often used to design or debug relational databases in the fields of software engineering, business information systems, education and research.
What is Erer diagram in DBMS?
ER Diagram stands for Entity Relationship Diagram, also known as ERD is a diagram that displays the relationship of entity sets stored in a database. In other words, ER diagrams help to explain the logical structure of databases. ER diagrams are created based on three basic concepts: entities, attributes and relationships.
What are Erer diagrams composed of?
ER Diagrams are composed of entities, relationships and attributes. They also depict cardinality, which defines relationships in terms of numbers. Here’s a glossary: A definable thing—such as a person, object, concept or event—that can have data stored about it. Think of entities as nouns.