0

is it necessary to have multi valued attributes in an entity to be present when there is a relationship for that multi valued attribute whith 1:m cardinality. for a example there is a table called tester and there is a multivalued att called raisedBugs and also there is a relationship with that tester entity called bugs which having tester_id as a foreign key(issue_assigner)

ER figure

Gayan Prasanna
  • 95
  • 1
  • 9

1 Answers1

0

The multiplicity of your associations depends on the functional requirements for the application. 1:m means that each bug has exactly one tester who raised it, so the tester_id must be non-null and filled with a valid id of a tester for each record. If your requirements are less strict, e.g. because you have bugs found by other people who are not on your database, the multiplicity would be 0,1:m, and the foreign key may be null.

TAM
  • 1,731
  • 13
  • 18
  • that's not the point i'm asking about.see the above updated question with the figure and tell that this multi valued raised_issues attribute is needed to be present in the iagram – Gayan Prasanna Mar 30 '16 at 14:35