Geek Answers Handbook

Problems Related to Entity Relationship Model Recommendations

I am currently enrolled in the Oracle Database Database Design online course, which briefly talks about the concept of untranslatable relationships. I understand the concept behind them, but the vague details of the course left me with a few questions.

  • Can there be indescribable relationships between objects that are associated with a 1: 1 or M: M ratio? The entire example provided by Oracle denotes a 1: M.

  • Is it possible to use the diamond used to represent an untranslatable relationship at both ends of the relationship, whether it is optional or mandatory? I believe that they can only appear at the obligatory end of a relationship, but I want to be sure.

  • Similarly, can the diamond used to represent an untranslatable relationship potentially appear at the BOTH ends of the relationship?

The following are a few examples provided by Oracle Academy: Example 1 Example2

+6
oracle12c entity-relationship-model
source share
1 answer

  • I'm not sure, but if you think about some 1: 1 relationships, they are indescribable. For example, one person can have only one passport. Passport cannot be transferred between people. I’m not sure about many, but I can come up with an example - you may have a group of people who write series of books. This would be a lot for many, and authorship cannot be transferred to other people. This is probably not a good example.

  • A diamond can be drawn on both sides, but usually it appears on the obligatory end, so I always put it on this end.

  • I have never seen a diamond at both ends.

+1
source share

More articles:


All Articles