10 Questions
Functional dependencies (FDs) are used to specify formal measures of the ______ of relational designs
goodness
And keys are used to define normal forms for ______
relations
The functional dependency (FD) is a relationship that exists between two ______
attributes
A set of attributes X functionally determines a set of attributes Y if the value of X determines a unique value for ______
Y
An instance of a relation that satisfies all such real-world constraints is called a legal instance of the relation; A legal instance of a database is one where all the relation instances are legal ______
instances
What are functional dependencies (FDs) used to specify?
Formal measures of the 'goodness' of relational designs
In database management, what does a set of attributes X functionally determine a set of attributes Y mean?
The value of X determines a unique value for Y
What is an instance of a relation that satisfies all real-world constraints called?
Legal instance of the relation
What are keys used for in database management?
To define normal forms for relations
What does the functional dependency (FD) represent?
A relationship between two attributes
Study Notes
Functional Dependencies (FDs)
- Functional dependencies (FDs) are used to specify formal measures of the integrity of relational designs.
- FDs are a relationship between two attributes.
Functional Determination
- A set of attributes X functionally determines a set of attributes Y if the value of X determines a unique value for Y.
- This means that if X is known, Y can be determined.
Legal Instances
- An instance of a relation that satisfies all real-world constraints is called a legal instance of the relation.
- A legal instance of a database is one where all the relation instances are legal.
Keys
- Keys are used to define normal forms for relational databases.
- Keys help to identify unique tuples in a relation.
Test your knowledge of Database Management Systems Functional Dependencies with this quiz. Challenge yourself with questions on FDs, keys, relational designs, and constraints. Prof. Shilpa S's expertise in the subject ensures a comprehensive assessment.
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