Closure of attributes in DBMS Theory - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find the closure of attribute set A under functional dependencies F.

DBMS Theory

SELECT closure FROM attribute_closure WHERE attributes = '[1]';

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AA+

BA

Cclosure

DF

Attempts:

3 left

💡 Hint

Common Mistakes

Using just 'A' instead of 'A+' for closure notation.

Confusing the closure with the set of functional dependencies.

The closure of attribute set A is denoted as A+ and includes all attributes functionally determined by A under F.

2fill in blank

medium

Complete the code to check if attribute B is in the closure of attribute set A.

DBMS Theory

IF '[1]' IN closure_of_A THEN RETURN TRUE ELSE RETURN FALSE;

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AC

BB

CA

DF

Attempts:

3 left

💡 Hint

Common Mistakes

Checking for attribute A instead of B.

Using the set of dependencies F instead of an attribute.

We check if attribute B is in the closure of A to determine if A functionally determines B.

3fill in blank

hard

Fix the error in the code to compute the closure of attribute set X under F.

DBMS Theory

closure = [1](X, F)

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Acompute_closure

Bclosure_compute

Cclosure

Dcompute

Attempts:

3 left

💡 Hint

Common Mistakes

Using incomplete or incorrect function names.

Using variable names instead of function names.

The standard function name to compute closure is often 'compute_closure'.

4fill in blank

hard

Fill both blanks to complete the code that computes closure of attributes in set S under dependencies D.

DBMS Theory

closure = [1]([2], D)

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Acompute_closure

BS

CX

DF

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping the function name and attribute set.

Using incorrect variable names.

The function to compute closure is 'compute_closure' and the attribute set is 'S'.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps each attribute in attrs to its closure under F.

DBMS Theory

closures = [1]: [2](attr, [3]) for attr in attrs

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Aattr

Bcompute_closure

CF

Dclosure

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong keys or values in the dictionary comprehension.

Confusing the function name or dependency set.

This comprehension creates a dictionary where each key is an attribute and the value is its closure computed by 'compute_closure' under dependencies F.