-
A
Eliminate all hidden dependencies
-
B
Eliminate the possibility of a insertion anomalies
-
C
Have a composite key
-
D
Have all non key fields depend on the whole primary key
A
Answer:
A
The relation in second normal form is also in first normal form and no partial dependencies on any column in primary key.
Tables in second normal form (2NF) are a stage of database normalization in which a table's primary key determines a unique set of non-key attributes. In other words, in a table in 2NF, all non-primary key columns are dependent on the primary key and do not repeat groups of data. This means that there is no partial dependency of non-primary key columns on the primary key. By having a table in 2NF, the data is less prone to data inconsistencies and is more scalable.
To bring a table to 2NF, it must first be in first normal form (1NF) which means that all repeating groups of data have been removed and each row has a unique identifier. Then, any non-primary key columns that are not dependent on the primary key should be removed and placed in a separate table with a foreign key referencing the primary key of the original table. This ensures that any non-key columns are only dependent on the primary key and not on other non-key columns.
SQL MCQs