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What is a functional dependency in database?
A functional dependency (FD) is a relationship between two attributes, typically between the PK and other non-key attributes within a table. For any relation R, attribute Y is functionally dependent on attribute X (usually the PK), if for every valid instance of X, that value of X uniquely determines the value of Y.
What is a functional dependency in the context of relational databases?
In relational database theory, a functional dependency is a constraint between two sets of attributes in a relation from a database. In other words, a functional dependency is a constraint between two keys.
What are functional dependencies used for?
Functional Dependency (FD) is a constraint that determines the relation of one attribute to another attribute in a Database Management System (DBMS). Functional Dependency helps to maintain the quality of data in the database. It plays a vital role to find the difference between good and bad database design.
What is meant by a functional dependency and give an example?
What is trivial functional dependency in databases?
Types of Functional Dependencies in DBMS Multivalued Dependency in DBMS. Multivalued dependency occurs in the situation where there are multiple independent multivalued attributes in a single table. Trivial Functional Dependency in DBMS. Non Trivial Functional Dependency in DBMS. Transitive Dependency in DBMS.
What is a functional dependency diagram?
Like a traditional architecture diagram, a dependency diagram identifies the major components or functional units of the design and their interdependencies. Each node on the diagram, called a layer, represents a logical group of namespaces, projects, or other artifacts. You can draw the dependencies that should exist in your design.
What is functional dependency in DBMS?
Functional dependency in DBMS. DBMSDatabaseMySQL. Functional dependency in DBMS, as the name suggests is a relationship between attributes of a table dependent on each other. Introduced by E. F. Codd, it helps in preventing data redundancy and gets to know about bad designs.