4.1 Consider the entity relationship diagram (ERD) below and answer the questions that follow - NSC Information Technology - Question 4 - 2023 - Paper 2
Question 4
4.1 Consider the entity relationship diagram (ERD) below and answer the questions that follow.
4.1.1 What is the purpose of an ERD?
4.1.2 Choose the most suitable ... show full transcript
Worked Solution & Example Answer:4.1 Consider the entity relationship diagram (ERD) below and answer the questions that follow - NSC Information Technology - Question 4 - 2023 - Paper 2
Step 1
What is the purpose of an ERD?
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Answer
An ERD provides a visual representation of how the data/tables are linked in a relational database. It allows for mapping and understanding the relationships between different entities, facilitating better database design.
Step 2
Choose the most suitable term from the list below for the part of the ERD above that is indicated by (a):
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a) Entity
Step 3
Choose the most suitable term from the list below for the part of the ERD above that is indicated by (b):
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b) One
Step 4
Choose the most suitable term from the list below for the part of the ERD above that is indicated by (c):
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c) Relationship
Step 5
Choose the most suitable term from the list below for the part of the ERD above that is indicated by (d):
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d) Many
Step 6
Name ONE other requirement of a primary key.
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A primary key cannot be null or empty; it must hold a unique value for each record.
Step 7
Critically analyse the design of the tblPlaylist table by explaining why the table does not adhere to the rules of normalisation:
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The table does not have a primary key, which means that identifying records uniquely is not possible.
There are repeating groups of fields since multiple songs for a genre are listed in the same row.
The 'Number of songs' can be calculated from the song fields, hence it is derived data and should not be stored directly in the table.
Step 8
Give a reason why it is more suitable to save the playlist information in a database rather than in a text file.
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Using a database allows for easier querying and filtering of data, better data integrity, and efficient data maintenance compared to a text file, where information can become disorganized and harder to manage.
