Database indexing in HLD - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the main purpose of a database index.

HLD

A database index is used to [1] data retrieval speed.

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Aignore

Bduplicate

Cincrease

Ddecrease

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing index with data duplication.

Thinking index slows down retrieval.

The main purpose of a database index is to increase data retrieval speed by allowing faster searches.

2fill in blank

medium

Complete the code to specify the common data structure used for database indexes.

HLD

Most database indexes use a [1] tree structure for efficient searching.

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Ahash

Bbinary

Clinked

DB+

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing binary tree which is not balanced for databases.

Confusing hash with tree structures.

B+ trees are commonly used in databases because they keep data sorted and allow fast insertion, deletion, and search.

3fill in blank

hard

Fix the error in the statement about index types.

HLD

A [1] index stores a mapping from keys to row locations using a hash function.

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Ahash

Bbitmap

Cclustered

Dfull-text

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing clustered index with hash index.

Choosing bitmap index which uses bitmaps, not hash functions.

Hash indexes use a hash function to map keys to row locations, enabling fast equality searches.

4fill in blank

hard

Fill both blanks to complete the description of clustered indexes.

HLD

A clustered index [1] the data rows in the table based on the index key, unlike a non-clustered index which [2] a separate structure.

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Asorts

Bstores

Cmaintains

Dcreates

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up 'stores' and 'sorts' for clustered index.

Thinking non-clustered index sorts data rows.

Clustered indexes sort the actual data rows according to the index key. Non-clustered indexes maintain a separate structure pointing to data.

5fill in blank

hard

Fill all three blanks to complete the code for a simple index creation statement.

HLD

CREATE [1] INDEX [2] ON [3] (column_name);

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AUNIQUE

Bidx_customer_name

Ccustomers

DTEMPORARY

Attempts:

3 left

💡 Hint

Common Mistakes

Using UNIQUE when temporary index is intended.

Mixing table and index names.

This statement creates a temporary index named 'idx_customer_name' on the 'customers' table.