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Entity Relationship Participation in Database
102 Lectures 7.5 hours
152 Lectures 16 hours
In a Relationship, Participation constraint specifies the existence of an entity when it is related to another entity in a relationship type. It is also called minimum cardinality constraint.
This constraint specifies the number of instances of an entity that can participate in a relationship type.
There are two types of Participation constraint −
Each entity in the entity set is involved in at least one relationship in a relationship set i.e. the number of relationship in every entity is involved is greater than 0.
Consider two entities Employee and Department related via Works_For relationship. Now, every Employee works in at least one department therefore an Employee entity exist if it has at least one Works_For relationship with Department entity. Thus the participation of Employee in Works_For is total relationship.
Total Participation is represented by double line in ER diagram.
Each entity in entity set may or may not occur in at least one relationship in a relationship set.
For example: Consider two entities Employee and Department and they are related to each other via Manages relationship. An Employee must manage a Department, he or she could be the head of the department. But not every Employee in the company manages the department. So, participation of employee in the Manages relationship type is partial i.e. only a particular set of Employees will manage the Department but not all.
- Importance of Entity-Relationship diagram in database design
- Entity-Relationship Diagram
- What is Entity-Relationship Modeling?
- Extended Entity-Relationship (EE-R) Model
- What is an Entity relationship model in DBMS?
- Binary Relationship in Database
- Ternary Relationship in Database
- N-ary Relationship in Database
- Mandatory and optional Participation
- Difference between Strong Entity and Weak Entity
- Explain difference between Strong Entity and Weak Entity
- Identifying Entity Relationships in DBMS
- Entity Integrity Rule in RDBMS
- HTML Entity Parser in C++
- Types of Entity Relationships in DBMS