Final answer:
Full functional dependency in a database system indicates that a set of attributes Y is entirely dependent on a set of attributes X, to the extent that removing any attribute from X would affect Y's dependency on X.
Step-by-step explanation:
In the context of database systems, a full functional dependency is a type of constraint between two sets of attributes in a relation. It means that a set of attributes Y is fully functionally dependent on a set of attributes X if Y is functionally dependent on X, and removing any attribute from X destroys the dependency.
This is to say, the relationship between X and Y is such that Y is entirely dependent on X for its value, and no subset of X can be removed without affecting the dependency of Y on X. Y is always necessary for X in their relationship, but X is not necessary for Y.
For example, consider a database table where we have student IDs and their corresponding names and enrollment details. Here, the student's name and enrollment details are fully functionally dependent on the student ID since the ID uniquely determines the name and enrollment details, and removing the ID would result in an inability to determine these values.
The concept of full functional dependency ensures that our data is properly normalized, which helps in reducing data redundancy and improving data integrity.