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4.1 Consider the entity relationship diagram (ERD) below and answer the questions that follow - NSC Information Technology - Question 4 - 2023 - Paper 2
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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 suitabl... 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?
Answer
An Entity Relationship Diagram (ERD) provides a visual representation of how the data/tables are linked in a relational database. This helps in understanding the relationships between different entities and ensures the logical structure of the database is correctly defined.
Step 2
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Step 7
Critically analyse the design of the tblPlaylist table by explaining why the table does not adhere to the rules of normalisation:
Answer
- The table lacks a primary key, which is essential for unique identification of records.
- There are repeating fields, which result in redundancy. For instance, songs are repeated for each genre rather than being stored in a separate linked table.
- The 'Number of songs' field should be calculated based on the entries in the songs columns, rather than manually entering it, making it prone to errors. When songs are added or removed, this field should be updated automatically.
Step 8
Give a reason why it is more suitable to save the playlist information in a database rather than in a text file.
Answer
Using a database allows for easier filtering of information, the ability to perform complex queries, and better maintenance of the data over time. This is in contrast to a text file, where data management functionalities are limited.