Column-store vs row-store in DBMS Theory - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to identify the storage type that stores data by rows.

DBMS Theory

In a [1] database, data is stored row by row.

Drag options to blanks, or click blank then click option'

Arow-store

Bgraph-store

Ccolumn-store

Ddocument-store

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing column-store with row-store.

A row-store database stores data row by row, meaning all columns of a row are stored together.

2fill in blank

medium

Complete the sentence to describe the main advantage of column-store databases.

DBMS Theory

Column-store databases are efficient for queries that access [1] of data.

Drag options to blanks, or click blank then click option'

Afew columns

Ball rows

Call columns

Dmany rows

Attempts:

3 left

💡 Hint

Common Mistakes

Assuming column-store reads entire rows.

Column-store databases are efficient when queries access only a few columns across many rows.

3fill in blank

hard

Fix the error in the statement about row-store databases.

DBMS Theory

Row-store databases store data by [1].

Drag options to blanks, or click blank then click option'

Acolumns

Bcells

Crows

Dtables

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing columns instead of rows.

Row-store databases store data by rows, meaning all columns of a single row are stored together.

4fill in blank

hard

Fill both blanks to complete the dictionary comprehension that selects columns with values greater than 10.

DBMS Theory

{col: data[col] for col in data if data[col] [1] 10 and col [2] 'id'}

Drag options to blanks, or click blank then click option'

A>

B<

C!=

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' for comparison.

Using '==' instead of '!=' for exclusion.

The comprehension selects columns where the value is greater than 10 and the column name is not 'id'.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps uppercase column names to their values if values are less than 50.

DBMS Theory

{ [1]: [2] for [3] in data if data[[3]] < 50 }

Drag options to blanks, or click blank then click option'

Acol.upper()

Bdata[col]

Ccol

Drow

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'row' instead of 'col' as the loop variable.

Not converting column names to uppercase.

This comprehension creates a dictionary with uppercase column names as keys and their values if the values are less than 50.