Consider the entity relationship diagram (ERD) below and answer the questions that follow - NSC Information Technology - Question 4 - 2023 - Paper 2
Question 4
Consider the entity relationship diagram (ERD) below and answer the questions that follow.
4.1.1 What is the purpose of an ERD? (2)
4.1.2 Choose the most suitable ... show full transcript
Worked Solution & Example Answer: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 helps to map the relationships between different entities and their attributes.
Step 2
Choose the most suitable term for (a) to (d)
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(a) A: Entity
(b) B: One
(c) C: Relationship
(d) D: Many
Step 3
Name ONE other requirement of a primary key.
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A primary key cannot be null or empty. It must always contain a unique value.
Step 4
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 tblPlaylist table violates the rules of normalisation for the following reasons:
No primary key: There is no unique identifier for each row in the table.
Repeating fields: The structure allows for multiple songs to be recorded in a single row, which is not a proper normal form. Each song should ideally be in a separate row.
Derived data: The 'Number of songs' field can be derived based on the songs listed, leading to redundancy.
Step 5
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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Storing playlist information in a database is more suitable because it allows for easier filtering and querying of data, providing a more efficient way to manage and retrieve information.