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How do you determine if two sets of functional dependencies are equivalent?
Definition: Two or more than two sets of functional dependencies are called equivalence if the right-hand side of one set of functional dependency can be determined using the second FD set, similarly the right-hand side of the second FD set can be determined using the first FD set.
How many functional dependencies are possible?
How many of those are there ? For each cardinality l of the LHS, there are 2^l possible subsets, each of those giving a trivial FD if it appears on the RHS. So the number of trivial FDs is 2^0 + 2^1 + 2^2 + + 2^n = 2^(n+1) – 1.
Can you distinguish between full functional dependency and partial dependency with an example?
In full functional dependency , the non-prime attribute is functionally dependent on the candidate key. In partial functional dependency , non-prime attribute is functionally dependent on part of a candidate key. In partial functional dependency, if we remove any attribute of X, then the dependency will still exist .
How to determine if two sets of functional dependencies are equivalent?
Two different sets of functional dependencies for a given relation may or may not be equivalent. Following steps are followed to determine whether F covers G or not- Take the functional dependencies of set G into consideration. For each functional dependency X → Y, find the closure of X using the functional dependencies of set G.
Is the relation your having two functional dependencies?
A relation R (A , C , D , E , H) is having two functional dependencies sets F and G as shown- Which of the following holds true? Functional dependencies of set F can determine all the attributes which have been determined by the functional dependencies of set G. Thus, we conclude F covers G i.e. F ⊇ G.
Which is the most important rule for functional dependency?
Below given are the Three most important rules for Functional Dependency: Reflexive rule –. If X is a set of attributes and Y is_subset_of X, then X holds a value of Y. Augmentation rule: When x -> y holds, and c is attribute set, then ac -> bc also holds.
How to use functional dependency in a database?
Here, are some key terms for Functional Dependency in Database: Key Terms Description Axiom Axioms is a set of inference rules used Decomposition It is a rule that suggests if you have a Dependent It is displayed on the right side of the Determinant It is displayed on the left side of the