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Fully-functional dependency in DBMS

In database management systems (DBMS), a fully-functional dependency is a relationship that exists between two attributes in a database. It indicates that the value of one attribute (the determinant) uniquely determines the value of another attribute (the dependent). In other words, if the value of the determinant attribute is known, the value of the dependent attribute can be uniquely determined.

For example, consider an employee database with the following attributes:

  • Employee ID (determinant)
  • Employee name (dependent)

In this database, the employee ID attribute is fully functionally dependent on the employee name attribute because the employee ID is uniquely determined by the employee name. This means that if the employee name is known, the employee ID can be uniquely determined.

Full functional dependencies are important in database design because they help to ensure the integrity, consistency, and security of the data in a database. They are used to enforce business rules, constraints, and policies on the data in a database, and they are used to maintain the integrity, consistency, and security of the data in a database.

Full functional dependencies can be used to identify and remove redundancy in a database. For example, if attribute A is fully functionally dependent on attribute B, then attribute A can be removed from the database because it can be derived from attribute B. This helps to reduce the amount of data stored in the database, and it helps to improve the performance of the database.

Full functional dependencies can also be used to identify and remove anomalies in a database. Anomalies are problems that can occur in a database when data is inserted, updated, or deleted. There are three types of anomalies: insertion anomalies, update anomalies, and deletion anomalies. Full functional dependencies can help to identify and remove these anomalies, and they can help to ensure the integrity, consistency, and security of the data in a database.

Full functional dependencies are used in the normalization process, which is the process of designing a database to reduce redundancy and eliminate anomalies. There are several normal forms that can be used to normalize a database, and full functional dependencies are used to identify and remove redundancy and eliminate anomalies in each normal form.

Full functional dependencies are also used in database security, and they are used to enforce access controls and permissions on the data in a database. For example, if attribute A is fully functionally dependent on attribute B, then access to attribute A can be restricted to users who have permission to access attribute B. This helps to ensure the security and privacy of the data in a database.

In summary, a fully-functional dependency is a relationship that exists between two attributes in a database. It indicates that the value of one attribute uniquely determines the value of another attribute. Full functional dependencies are important in database design because they help to ensure the integrity, consistency, and security of the data in a database. They are used to enforce business rules, constraints, and policies on the data in a database, and they are used to maintain the integrity, consistency, and security of the data in a database.