Contents
- 1 What do you mean by many-to-many relationship between student and course entity?
- 2 What do you mean by many to one relationship between employee and department table?
- 3 What relationship does exist between a company and its departments?
- 4 What are the attributes of a student entity?
- 5 What does one to one relationship in database mean?
- 6 What do you need to know about entity relationships?
What do you mean by many-to-many relationship between student and course entity?
Many-to-Many Relationship It means one Student can enroll for many Courses and also, one Course can be taught to many Students. The database includes the StudentCourse joining table which includes the primary key of both the tables ( Student and Course tables).
What do you mean by many to one relationship between employee and department table?
One-to-Many and Many-to-One Relationships To define tables for each one-to-many and many-to-one relationship: Group all the relationships for which the “many” side of the relationship is the same entity. Define a single table for all the relationships in a group.
How do you resolve a many to many relationship?
The key to resolve m:n relationships is to separate the two entities and create two one-to-many (1:n) relationships between them with a third intersect entity. The intersect entity usually contains attributes from both connecting entities.
What relationship does exist between a company and its departments?
Consider the possible relationships between employees and departments. If a given employee can work in only one department, this relationship is one-to-one for employees. One department usually has many employees; this relationship is one-to-many for departments.
What are the attributes of a student entity?
In the above example of STUDENT entity, Student has ID, name, address, DOB, class in which he is studying are all called as attribute of STUDENT entity. It’s also known as columns of the table.
Which is an example of a many to many relationship?
A many-to-many relationship occurs when multiple records in a table are associated with multiple records in another table. For example, a many-to-many relationship exists between customers and products: customers can purchase various products, and products can be purchased by many customers.
What does one to one relationship in database mean?
A one to one (1:1) relationship is the relationship of one entity to only one other entity, and vice versa. It should be rare in any relational database design. In fact, it could indicate that two entities actually belong in the same table.
What do you need to know about entity relationships?
Another term to know is entity type which defines a collection of similar entities. An entity set is a collection of entities of an entity type at a particular point of time. In an entity relationship diagram (ERD), an entity type is represented by a name in a box.