What is an Entity Relationship Diagram (ER Diagram)?An ER diagram shows the relationship among entity sets. An entity set is a group of similar entities and these entities can have attributes. In terms of DBMS, an entity is a table or attribute of a table in database, so by showing relationship among tables and their attributes, ER diagram shows the complete logical structure of a database. Lets have a look at a simple ER diagram to understand this concept.A simple ER Diagram:In the following diagram we have two entities Student and College and their relationship. The relationship between Student and College is many to one as a college can have many students however a student cannot study in multiple colleges at the same time. Student entity has attributes such as Stu_Id, Stu_Name & Stu_Addr and College entity has attributes such as Col_ID & Col_Name.

Question

Lalitesh sharma · Accepted Answer

What is an Entity Relationship Diagram (ER Diagram)?An ER diagram shows the relationship among entity sets. An entity set is a group of similar entities and these entities can have attributes. In terms of DBMS, an entity is a table or attribute of a table in database, so by showing relationship among tables and their attributes, ER diagram shows the complete logical structure of a database. Lets have a look at a simple ER diagram to understand this concept.A simple ER Diagram:In the following diagram we have two entities Student and College and their relationship. The relationship between Student and College is many to one as a college can have many students however a student cannot study in multiple colleges at the same time. Student entity has attributes such as Stu_Id, Stu_Name & Stu_Addr and College entity has attributes such as Col_ID & Col_Name.

Cardinality expresses the number of entity occurrences associated with one occurrence of the related entity

The Entity Customer has three candidate keys: a) CustId b) Email and c) ContactNo. Suggest the best primary key for thi...

Generalization is a bottom-up design process that combines a number of entity sets, which share the same features into ...

A subtype entity_____?

An identifier of an entity instance?

A weak entity is one which _____?

Which of the following is another name for weak entity?

E-R model uses this symbol to represent weak entity set ?

Which forms have a relation that contains information about a single entity?

E-R model uses this symbol to represent weak entity set ?

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