Contents
How can we convert ER diagram into relation?
To convert this Relationship set into relational schema,
- Relationship set is mapped as separate relation.
- Key attributes of participating entity sets are mapped as primary key for that relation.
- Attribute of relationship set becomes simple attributes for that relation.
What are tables in ER Diagram?
In the given ER diagram, LECTURE, STUDENT, SUBJECT and COURSE forms individual tables. All single-valued attribute becomes a column for the table.
Why is aggregation defined in ER diagram?
The Aggregation method is applied to create a relationship between an entity and the other entities of the same level, and the resulting artifact is aggregated further into a higher level This helps in identifying the entity formed as a result of Aggregation in the hierarchical Entity Relationship system.
How to create ER diagram for existing SQL Server database?
SSMS editor comes with one useful function. You can automatically add all the tables related to a particular table (with a foreign key relationship) to the diagram. To do it, right click on the table and choose Add Related Tables. 4.
Can a ER diagram be converted to a table?
There are some points for converting the ER diagram to the table: Entity type becomes a table. In the given ER diagram, LECTURE, STUDENT, SUBJECT and COURSE forms individual tables.
How to map the ER model to relational DBS?
Mapping #3 (1-MANY RELATIONSHIP): 1-1 and 1-manyrelationships between separate entitites need not be mapped to a relation; the primary key attributes of the “1” relation become foreign key attributes of the “many” relation If no “Since” attribute, the relations could be (with some appropriate attribute renaming and additions)
How is multivalued attribute represented in ER diagram?
In the given ER diagram, COURSE_ID, STUDENT_ID, SUBJECT_ID, and LECTURE_ID are the key attribute of the entity. The multivalued attribute is represented by a separate table. In the student table, a hobby is a multivalued attribute. So it is not possible to represent multiple values in a single column of STUDENT table.