It specify the number of relationship instances that an entity can participate in.
The cardinality ratio specifies the number of relationship instances that an entity can participate in.
In mathematics, the cardinality of a set is a measure of the "number of elements of the set". For example, the set A = {2, 4, 6} contains 3 elements, and therefore A has a cardinality of 3. There are two approaches to cardinality - one which compares sets directly using bijections and injections, and another which uses cardinal numbers.
The cardinality of [0,1) is equal to the cardinality of (0,1) which has the same cardinality as the real numbers.
Cardinality is the number of attributes in the table.
ratio
The cardinality ratio specifies the number of relationship instances that an entity can participate in.
An E-R diagram may also indicate the cardinality of a relationship. Cardinality is the number of instances of one entity that can, or must, be associated with each instance of another entity. In general we may speak of one-to-one, one-to-many, or many-to-many relationships. There are several different styles used to draw Entity-Relationship diagrams. The Kendall and Kendall text uses the Crow's Foot notation. Using this notation entities are represented by rectanges and relationships are indicated by lines connecting the rectangles. Cardinality is shown by a series of "tick marks" and "crows feet" superimposed on the relationship lines.
Extended ER diagram is a variant of ER diagram. EER include ER diagram + hierarichal concept. Extended ER diagram is also called Enhance ER diagram(EER).
An ER diagram for a school management system typically includes entities such as Student, Teacher, Course, Classroom, and Enrollment. Relationships between these entities can be depicted using cardinality and participation constraints to show how they are connected (e.g., a student enrolls in courses taught by teachers in specific classrooms). The ER diagram serves as a visual representation of the database schema for the school management system.
supermarket (ER-Diagram)
I 'm need ER diagram for websit news
ER Diagram of online shopping
Er diagram of on line shopping
In mathematics, the cardinality of a set is a measure of the "number of elements of the set". For example, the set A = {2, 4, 6} contains 3 elements, and therefore A has a cardinality of 3. There are two approaches to cardinality - one which compares sets directly using bijections and injections, and another which uses cardinal numbers.
How do you draw a ER diagram for a automobile industry?
draw the er diagram for tours
You also can draw your ER diagram by so many ways. A software called Edraw is a better software to draw the ER diagram. This one has some ready-to-use ER diagrams templates conceptdraw.com/How-To-Guide/er-diagram