* Describe functional dependencies and normalization * Denormalization, if any (
ID: 3721742 • Letter: #
Question
* Describe functional dependencies and normalization
* Denormalization, if any (which ones and why) and The normal form (3NF, BCNF, etc) of tables/relationship. Justify the reasons if any of them is below 3NF.
support Custom_name player_name account profile_status Name A id email password birth_date pflag cflag dflag S id C id c_name g_name community develop g_id name g id rating price s_id game interact C name A name play hours g_ name a_name shopping cart payment payment type Be friend f_namea f_namebExplanation / Answer
A functional dependency defines a functional relationship between attributes
In the above example, functional dependecies are
Support(Custom_Name) -> Account(Name)
Support(Player_Name) -> Account(Name)
Be_friend(f_namea) -> Account(Name)
Be_friend(f_nameb) -> ?Account(Name)
play(a_name) -> ?Account(Name)
develop(a_id) -> Account(Name)
interact(c_name) -> community(c_name)
play(g_name) -> ?game(g_name)
community(g_name) -> ?game(g_name)
develop(g_id) ->game(g_name)
game(s_id) -> shopping_cart(s_id)
account(s_id) -> shopping_cart(s_id)
Normalization is a method to remove all these anomalies and bring the database to a consistent state.
Account table is not normalized, it is in 2NF form as there are many attributes which are not dependant on each other, yet they are in same table. E.g, flags and account info can be separated.
a_id -> a_name, email, password, profile_status, birth_date, s_id
a_id -> nDevelop, dflag,pflag,cflag
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