ER Diagram Cardinality Symbols
In this tutorial, we will learn different ER Diagram Cardinality Symbols. The relationships are indicated using lines drawn from one table to another and a symbol at the end which defines the relationship type. ERD acronym stands for Entity-Relationship Diagram.
ER Diagram is an output of the modeling process.
Cardinality is the maximum number of times an instance of an entity can be associated with instances of another entity s shown in the ER diagrams. Ordinality is the minimum number of times an instance of an entity can be associated with an instance in another entity.
Cardinality/Ordinality are shown by styling the relationship line and its endpoint with cardinality symbols. Some basic symbols in Crow’s Foot notation are as follows:
1-to-0 ( or 1) Relationship
1-to-0 ( or 1) Relationship can be represented as shown below. Each instance of Entity A is related to a minimum of zero and a maximum of one instance of Entity B.
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