Tshepo is a visionary leader with great ideas for his group of companies. But his background is in electronic engineering, not software development. He has decided that he needs to understand most of the jargon around databases and datamodels before he will feel comfortable with participating in the process to design the carbon accounting database.
Question 2
Tshepo is a visionary leader with great ideas for his group of companies. But his background is in electronic engineering, not software development. He has decided that he needs to understand most of the jargon around databases and datamodels before he will feel comfortable with participating in the process to design the carbon accounting
Answer his questions below, providing examples that are relevant to ACME Technologies wherever possible.
Q.2.1
Tshepo wants to know what the difference is between one‐to‐many, many‐to‐ many and one‐to‐one relationships. For each of the below relationships, provide an explanation of what it is and a relevant example.
Q.2.1.1One‐to‐many relationship.
Q.2.1.2 Many‐to‐many relationship.
Q.2.1.3 One‐to‐one relationship.
Q.2.2
Two interns were overheard arguing over which notation to use for entity relationship diagrams – Crow’s Foot, Chen or Unified Modelling Language (UML). It would be useful to see the three types of diagrams next to each other for comparison. Draw the below relationship in each of the three notations.
“A space station orbits around one and only one planet.
A planet may have none, one or more space stations in orbit around it.”
Q.2.2.1Crow’s Foot.
Q.2.2.2Chen.
Q.2.2.3 Unified Modelling Language (UML).
Q.2.3 Somebody told Tshepo that data redundancy causes problems. And yet he has seen database designs that have foreign keys that look to him like duplicate data.
Q.2.3.1 Explain what foreign keys are.
Q.2.3.2 Explain why foreign keys are not redundant data.
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