16 Questions
What is the main requirement for a database to be in First Normal Form (1NF)?
All rows must be unique with no duplicate rows
In the context of database normalization, what is the solution for the problem of identical rows?
Add an order ID as a primary key
What is the main requirement for a database to be in Second Normal Form (2NF)?
The database must be in First Normal Form
What is a candidate key in the context of database normalization?
A key that uniquely identifies each row in a table and is used to ensure no duplicate or ambiguous records
What is the solution for the problem of each cell containing a single value in First Normal Form?
Create a separate table with order items
What is the main requirement for a database to be in Third Normal Form (3NF)?
All non-prime attributes should be fully functionally dependent on the candidate key
Which type of key is a set of attributes that can uniquely identify a tuple, except for the primary key?
Candidate key
In a relational database, what is the primary purpose of a super key?
To uniquely identify any record or row of data from the table
Which type of key is used to point to the primary key of another table?
Foreign key
What kind of dependency occurs when one non-prime attribute is dependent on another non-prime attribute?
Transitive dependency
Which type of key uniquely identifies one and only one instance of an entity in a relational database?
Primary key
In the context of a relational database, what is the most suitable key used to uniquely identify any record or row of data from a table?
Primary key
If a table is not in 2NF because the Course Fee is only dependent on the primary key to determine the course fee, what kind of dependency does this represent?
Partial dependency
What type of keys are as strong as the primary key and can uniquely identify a tuple in a relation?
Candidate keys
In a relational database, which type of keys are used to uniquely identify any record or row of data from the table?
Primary keys
What kind of keys are used to point to the primary key of another table in a relational database?
Foreign keys
Study Notes
Database Normalization
- A database is in First Normal Form (1NF) if each cell contains a single value.
- The solution for the problem of identical rows is to eliminate duplicate rows.
- A database is in Second Normal Form (2NF) if it is in 1NF and all non-prime attributes are fully functional dependent on the primary key.
- A candidate key is a set of attributes that can uniquely identify a tuple in a relational database.
- A primary key is a type of candidate key that is selected to uniquely identify an entity in a relational database.
Types of Keys
- A super key is a set of attributes that can uniquely identify a tuple, and is used to identify any record or row of data from a table.
- A foreign key is used to point to the primary key of another table in a relational database.
- Alternate keys are as strong as the primary key and can uniquely identify a tuple in a relation.
- The primary key is the most suitable key used to uniquely identify any record or row of data from a table.
Dependency
- Transitive dependency occurs when one non-prime attribute is dependent on another non-prime attribute.
- Partial dependency occurs when a non-prime attribute is dependent on only one part of the primary key, such as the Course Fee being dependent on the Course ID.
Key Concepts
- A primary key uniquely identifies one and only one instance of an entity in a relational database.
- A foreign key is a type of key used to point to the primary key of another table in a relational database.
Test your knowledge of database normalization concepts such as 1NF, 2NF, and 3NF. This quiz covers identifying unique rows, ensuring single values in cells, and organizing data to meet normalization requirements.
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