Why Is Sno, Pno=>Qty, Sname=>Qty in 3NF?

  • Comp Sci
  • Thread starter shivajikobardan
  • Start date
In summary, the conversation discusses the concept of third normal form (3NF) and how it applies to the given functional dependencies (FDs). The participants agree that for the first two FDs (Sno,Pno=>Qty and Sname,Pno=>Qty), the LHS is a super key and the RHS is a non-prime attribute, making them in 3NF. However, there is a disagreement about the last two FDs (Sno=>Sname and Sname=>Sno). While one participant argues that they are not in 3NF because they do not follow the rule of LHS being a super key, the other participant points out that they serve as lookup tables to translate between sno and sname.
  • #1
shivajikobardan
674
54
Homework Statement
3NF third normal form
Relevant Equations
none
Sno,Pno=>Qty
Sname,Pno=>Qty
Sno=>Sname
Sname=>Sno

To be in 3NF, LHS should be super key and RHS should be non-prime attribute.
It holds true for first 2 FDs. But for the last two, it doesn't hold true. So, why is it in 3NF?
chatGPT says it holds true for all FDs, but I can't see how.
 
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  • #2
The last two look like lookup tables to translate between sno and sname. Given sno I can find sname and given sname I can find sno.
 
  • #3
shivajikobardan said:
Homework Statement:: 3NF third normal form
Relevant Equations:: none

Sno,Pno=>Qty
Sname,Pno=>Qty
Sno=>Sname
Sname=>Sno
This is impossible to answer without knowledge of what data are contained in the columns, however assuming Sname represents a person's name, and given the fact that two people can have the same name what do you think about your statement that Sname,Pno=>Qty is in 3NF?
 

1. Why is it important to normalize a database into 3NF?

Normalizing a database into 3NF (Third Normal Form) helps to eliminate data redundancy and inconsistencies, making the database more efficient, organized, and easier to maintain. It also ensures that the data is stored in a logical and structured manner, which improves data integrity and reduces the chances of data anomalies.

2. What is the difference between 1NF, 2NF, and 3NF?

1NF (First Normal Form) deals with eliminating repeating groups of data within a single record. 2NF (Second Normal Form) deals with eliminating partial dependencies by creating separate tables for related data. 3NF (Third Normal Form) deals with eliminating transitive dependencies by creating separate tables for non-key attributes.

3. How does normalizing a database into 3NF improve data integrity?

By eliminating data redundancy and ensuring that data is stored in a logical and structured manner, normalizing a database into 3NF helps to improve data integrity. This means that the data is accurate, consistent, and reliable, which is essential for making informed decisions based on the data.

4. Can a database be in both 2NF and 3NF?

Yes, a database can be in both 2NF and 3NF. This means that the database has been normalized to eliminate partial dependencies and transitive dependencies, making it more efficient and organized.

5. What is the process of normalizing a database into 3NF?

The process of normalizing a database into 3NF involves the following steps: 1) Identify the functional dependencies within the data, 2) Eliminate any partial dependencies by creating separate tables for related data, 3) Eliminate any transitive dependencies by creating separate tables for non-key attributes, and 4) Ensure that each table has a primary key and that all other attributes are directly dependent on the primary key.

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