Canonical cover in DBMS Theory - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a canonical cover in database theory.

DBMS Theory

A canonical cover is a minimal set of functional dependencies that is [1] to the original set.

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Aequivalent

Blarger

Cunrelated

Dsimpler

Attempts:

3 left

💡 Hint

Common Mistakes

Thinking the canonical cover is larger than the original set.

Confusing equivalence with simplification only.

A canonical cover is a minimal set of functional dependencies that is equivalent to the original set, meaning it preserves the same closure.

2fill in blank

medium

Complete the code to describe a step in finding a canonical cover.

DBMS Theory

One step in finding a canonical cover is to [1] extraneous attributes from functional dependencies.

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Aadd

Bduplicate

Cignore

Dremove

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to add attributes instead of removing them.

Ignoring extraneous attributes and not simplifying.

Removing extraneous attributes helps simplify the functional dependencies without changing their meaning.

3fill in blank

hard

Fix the error in the statement about canonical cover.

DBMS Theory

A canonical cover must have [1] functional dependencies than the original set.

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Afewer

Brandom

Cequal

Dmore

Attempts:

3 left

💡 Hint

Common Mistakes

Assuming the canonical cover has more dependencies.

Confusing minimal with random or equal.

A canonical cover has fewer or equal functional dependencies, but it is minimal, so usually fewer.

4fill in blank

hard

Fill both blanks to complete the process of canonical cover simplification.

DBMS Theory

To simplify, first [1] the right side of dependencies to single attributes, then [2] extraneous attributes from the left side.

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Adecompose

Bcombine

Cremove

Dadd

Attempts:

3 left

💡 Hint

Common Mistakes

Combining right sides instead of decomposing.

Adding attributes instead of removing extraneous ones.

Decomposing the right side ensures each dependency has a single attribute on the right. Then removing extraneous attributes from the left side simplifies the dependencies.

5fill in blank

hard

Fill all three blanks to complete the canonical cover definition code snippet.

DBMS Theory

canonical_cover = [1]: [2] for [3] in functional_dependencies if not is_redundant([3])}

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Afd.left_side

Bfd.right_side

Cfd

Dfd.attributes

Attempts:

3 left

💡 Hint

Common Mistakes

Using attributes instead of left or right sides.

Using wrong variable names causing errors.

This code creates a dictionary where keys are the left sides of functional dependencies, values are the right sides, and only includes dependencies that are not redundant.