FUNCTIONAL DEPENDENCY PDF FREE

A Simple Guide to Five Normal Forms in Relational Database.The Application of Functional Dependency Theory to Relational Databases.Heavier reading but well worth the effort. The Relational Data Model: Functional-Dependency Theory.Functional Dependencies and Normalization for Relational Databases.The following are 'slide shows' from various academic sites.

FUNCTIONAL DEPENDENCY PDF FREE

Here are a few free resources about Functional Dependencies, Normalization and database design.Д«e prepared to exercise your brain and math skills when studying this material. Fourth and fifth normal forms involve Multi-Valued dependencies (another kettle of fish). How a given set of relations represent functional dependencies. The first 3 normal forms, including Boyce Codd Normal Form (BCNF) is stated in terms of

Sets of functional dependencies may be used to synthesize relations (tables). Given a BirthDate we may find many PersonId sharing that date.

Many people may have been born on the same day. Note that the converse may or may not be true. Another way of saying this is: There is exactly one Birth Date for any given instance of a person. For example: PersonId functionally determines BirthDate (normally written as PersonId -> BirthDate). In Fc, no functional dependency should contain an extraneous attribute and each left side of functional dependency should be unique.A functional dependency defines a functional relationship between attributes. A _ Fc for F is a set of dependencies such that F logically implies all dependencies in Fc, and Fc logically implies all dependencies in F.Д¬larification: A Canonical cover Fc for F is a set of dependencies such that F logically implies all dependencies in Fc, and Fc logically implies all dependencies in F. We say that a decomposition having the property FвЂ™+ = F+ is a _ decomposition.Д¬larification: We say that a decomposition having the property FвЂ™+ = F+ is a dependency preserving decomposition.ДЎ0. If B is an attribute and Aв†’B, Then B is said to be _ by a.Д¬larification: If B is an attribute and Aв†’B, Then B is said to be functionally determined by a.Д©. The other two options are specified in the question itself.ДЁ. If Aв†’B, Aв†’ C then which of the following is true?Д¬larification: Applying the union rule to the given question, we get, Aв†’BC is true.

This is the transitivity rule of ArmstrongвЂ™s axioms.Д§. State true or false: Functional dependencies are transitiveД¬larification: All functional dependencies are transitive. Armstrong axioms are called sound because?Д«) They cannot generate correct functional dependenciesД¬) They allow us to generate the complete closureД) They cannot generate incorrect functional dependenciesД¬larification: ArmstrongвЂ™s axioms are called as sound axioms because they do not generate incorrect functional dependencies.Д¦. State true or false: ArmstrongвЂ™s axioms allow us to generate all F+ for any given FД¬larification: ArmstrongвЂ™s axioms allow us to generate all F+ for any given F and hence are called complete.ДҐ. This is called the reflexivity rule of ArmstrongвЂ™s axioms.Д¤. If a functional dependency is reflexive, B is a subset of A and A is the set of attributes, thenД¬larification: If a functional dependency is reflexive, B is a subset of A and A is the set of attributes, then Aв†’B holds. It is the set of all functional dependencies logically implied by F.ДЈ. If F is a set of functional dependencies, then the closure of F is denoted by?Д¬larification: If F is a set of functional dependencies, then the closure of F is denoted by F+. A functional dependency f on R is logically implied by a set of functional dependencies F on r if every instance of r(R) that satisfies F also satisfies f.Дў. We say such FDs are logically implied by F. A functional dependency f on R is _ by a set of functional dependencies F on r if every instance of r(R) that satisfies f also satisfies F.Д¬larification: Given a set F of functional dependencies on a schema, we can prove that certain other functional dependencies also hold on that schema. RDBMS Multiple Choice Questions on вЂњFunctional Dependency TheoryвЂќ.ДЎ.

Functional dependency pdf