Why We Need to Compare Functional Dependencies?

Suppose in the designing process we convert the ER diagram to a relational model and this task is given to two different engineers. Now those two engineers give two different sets of functional dependencies. So, being an administrator we need to ensure that we must have a good set of Functional Dependencies. To ensure this we require to study the equivalence of Functional Dependencies.

Equivalence of Functional Dependencies

For understanding the equivalence of Functional Dependencies Sets (FD sets), the basic idea about Attribute Closure is given in this article Given a Relation with different FD sets for that relation, we have to find out whether one FD set is a subset of another or both are equal. 

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How To Find the Relationship Between Two Functional Dependency Sets?

Let FD1 and FD2 be two FD sets for a relation R....

Why We Need to Compare Functional Dependencies?

Suppose in the designing process we convert the ER diagram to a relational model and this task is given to two different engineers. Now those two engineers give two different sets of functional dependencies. So, being an administrator we need to ensure that we must have a good set of Functional Dependencies. To ensure this we require to study the equivalence of Functional Dependencies....

Advantages

It can help to identify redundant functional dependencies, which can be eliminated to reduce data redundancy and improve database performance. It can help to optimize database design by identifying equivalent sets of functional dependencies that can be used interchangeably. It can ensure data consistency by identifying all possible combinations of attributes that can exist in the database....

Disadvantages

The process of determining the equivalence of functional dependencies can be computationally expensive, especially for large datasets. The process may require testing multiple candidate sets of functional dependencies, which can be time-consuming and complex. The equivalence of functional dependencies may not always accurately reflect the semantic meaning of data, and may not always reflect the true relationships between data elements....

Sample Questions

Q.1 Let us take an example to show the relationship between two FD sets. A relation R(A,B,C,D) having two FD sets FD1 = {A->B, B->C, AB->D} and FD2 = {A->B, B->C, A->C, A->D}...

Frequently Asked Questions

1. What is Functional Dependency?...