Changes between Version 4 and Version 5 of Normalization


Ignore:
Timestamp:
08/29/26 05:11:39 (9 days ago)
Author:
232012
Comment:

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  • Normalization

    v4 v5  
    1414    shipping_address,
    1515    telephone_number,
     16    admin_id,
    1617    admin_type,
    1718    discount_percentage,
    … …  
    2728    release_date,
    2829    cover_photo,
     30    album_id,
    2931    duration,
    3032    song_id,
    … …  
    8082{{{#!div style="text-align: justify; width: 100%;"
    8183**LHS only:**\\
    82 artist_id, song_id, product_id, order_id, modification_id 
     84artist_id, song_id, product_id, order_id, modification_id, album_id
    8385
    8486**RHS only:**\\
    … …  
    9193== Candidate Keys and Primary Key
    9294
     95{{{#!div style="text-align: justify; width: 100%;"
     96When identifying a candidate key, we first consider the attributes that appear only on the left-hand side (LHS) of the functional dependencies:
     97
     98**{artist_id, song_id, product_id, order_id,modification_id, album_id}**
     99
     100These attributes cannot be derived from any other attributes using the given functional dependencies, so they must be included in a candidate key.
     101
     102Therefore, we initially define:
     103
     104**K = {order_id, product_id, artist_id, song_id, modification_id, album_id}**
     105
     106The closure K+ contains all attributes of the universal relation R. Therefore, K is a superkey.  Each attribute in K is necessary because removing any one of them prevents at least one set of attributes of R from being derived. Therefore, K is minimal and the selected primary key for the initial de-normalized relation is:
     107
     108**(order_id, product_id, artist_id, song_id, modification_id, album_id)**
    93109
    94110