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4.1.1 Explain the concept of database normalisation in the design of a database - NSC Information Technology - Question 4 - 2024 - Paper 2
Question 4
4.1.1 Explain the concept of database normalisation in the design of a database. 4.1.2 A relationship needs to be created between the tblArtists and tblShows tables... show full transcript
Worked Solution & Example Answer:4.1.1 Explain the concept of database normalisation in the design of a database - NSC Information Technology - Question 4 - 2024 - Paper 2
Step 1
Explain the concept of database normalisation in the design of a database.
Answer
Database normalisation is the process of organising data in a database or adapting its design to eliminate anomalies and reduce data redundancy. It involves structuring a relational database in such a way that different data entities are stored in separate tables, and relationships between those tables are defined. This helps ensure that each piece of data resides in its appropriate table and minimizes duplication, leading to a more efficient and manageable database system.
Step 2
(a) This relationship should allow each show to be performed by one artist, and each artist to be able to perform in many shows. Explain how this one-to-many relationship can be properly created by implementing the appropriate primary key/foreign key relationship in the design of the tables.
Answer
To create a one-to-many relationship between the tblArtists and tblShows tables, a foreign key is implemented in the tblShows table. The primary key, ArtistID, from the tblArtists table will reference this foreign key in tblShows. This allows each show (tblShows) to be linked to one artist (tblArtists), while permitting the same artist to be associated with multiple shows. The design enhances data integrity and relationship by ensuring that each show is correctly mapped to its respective artist.
Step 3
(b) Identify the redundant field in tblArtists and motivate your answer.
Answer
The redundant field in tblArtists may be the NumberOfShows, as this information can be derived or calculated from the tblShows table by counting the number of shows associated with each artist. Storing this information in tblArtists could lead to inconsistencies, especially if updates occur in tblShows, meaning NumberOfShows in tblArtists could become outdated. Thus, it's more efficient to eliminate this field and calculate it dynamically.
Step 4
Explain what is meant by the term logical integrity.
Answer
Logical integrity refers to how accurate and consistent the data in a database is. It ensures that the data adheres to defined rules and constraints, making certain that it retains its intended meaning and can be used correctly during database operations. For instance, identification of unique records and avoidance of duplicates are critical for maintaining logical integrity.