HBase data model (column families) in Hadoop - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a column family in HBase table creation.

Hadoop

create 'my_table', '[1]'

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

A'value'

B'rowkey'

C'column1'

D'cf1'

Attempts:

3 left

💡 Hint

Common Mistakes

Using row key or column qualifier names instead of column family names.

Omitting the quotes around the column family name.

In HBase, column families are defined during table creation using their names like 'cf1'.

2fill in blank

medium

Complete the code to add a new column family to an existing HBase table.

Hadoop

alter '[1]', 'cf2'

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

A'new_table'

B'my_table'

C'cf1'

D'row1'

Attempts:

3 left

💡 Hint

Common Mistakes

Using a column family name instead of the table name in the alter command.

Using a non-existent table name.

The 'alter' command modifies an existing table, so the table name must be correct.

3fill in blank

hard

Fix the error in the HBase shell command to create a table with two column families.

Hadoop

create 'test_table', '[1]', 'cf2'

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

A'cf1'

B'cf1', 'cf3'

Ccf1

D'cf1 cf3'

Attempts:

3 left

💡 Hint

Common Mistakes

Not quoting the column family name.

Combining multiple column families into one string.

Each column family must be a separate quoted string. The correct syntax is to list them as separate quoted strings.

4fill in blank

hard

Fill both blanks to define a table with two column families 'cf1' and 'cf2' in HBase shell.

Hadoop

create 'my_table', [1], [2]

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

A'cf1'

B'cf2'

C'cf3'

D'cf4'

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect column family names.

Combining column families into one string.

The create command requires each column family as a separate quoted string.

5fill in blank

hard

Fill all three blanks to create a table 'sales' with column families 'info', 'data', and 'metrics'.

Hadoop

create '[1]', [2], [3], 'metrics'

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

A'sales'

B'info'

C'data'

D'metrics'

Attempts:

3 left

💡 Hint

Common Mistakes

Placing column families in the wrong order.

Not quoting the table name or column families.

The table name is the first argument, followed by each column family as separate quoted strings.

Practice

1. What is the main purpose of column families in HBase?

easy

A. To encrypt data automatically

B. To store data in rows instead of columns

C. To create indexes for faster searching

D. To group related columns together for better organization

Solution

1. Step 1: Understand the role of column families

   Column families group related columns in HBase tables to organize data logically.

2. Step 2: Identify the main purpose

   This grouping helps manage storage and access efficiently by keeping related data together.

3. Final Answer:

   To group related columns together for better organization -> Option D

4. Quick Check:

   Column families = Group related columns [OK]

Hint: Think of column families as folders grouping related files [OK]

Common Mistakes:

• Confusing column families with rows
• Thinking column families create indexes
• Assuming column families encrypt data

2. Which of the following is the correct way to define a column family in an HBase table schema?

easy

A. create 'mytable', 'cf1'

B. CREATE TABLE mytable (rowkey STRING, cf1:col1 STRING)

C. INSERT INTO mytable (cf1) VALUES ('value')

D. ALTER TABLE mytable ADD COLUMN cf1

Solution

1. Step 1: Recall HBase shell syntax for creating tables

   In HBase shell, tables are created with column families using: create 'table_name', 'column_family'

2. Step 2: Match the correct syntax

   create 'mytable', 'cf1' matches this syntax exactly, defining 'cf1' as a column family.

3. Final Answer:

   create 'mytable', 'cf1' -> Option A

4. Quick Check:

   HBase create table syntax = create 'table', 'cf' [OK]

Hint: Use HBase shell syntax: create 'table', 'column_family' [OK]

Common Mistakes:

• Using SQL syntax instead of HBase shell
• Trying to add columns like in relational DBs
• Confusing insert with create commands

3. Given an HBase table with column families cf1 and cf2, what happens if you insert data only into cf1:colA for a row?

medium

A. Only cf1:colA stores data; cf2 columns remain empty for that row

B. Data is automatically copied to cf2

C. The row is rejected because all column families must have data

D. The entire row is deleted

Solution

1. Step 1: Understand column family independence

   In HBase, column families are independent; data can be stored in any family without affecting others.

2. Step 2: Analyze the effect of inserting data into one family

   Inserting data into cf1:colA stores data only there; cf2 columns remain empty for that row.

3. Final Answer:

   Only cf1:colA stores data; cf2 columns remain empty for that row -> Option A

4. Quick Check:

   Column families store data independently [OK]

Hint: Data in one column family doesn't affect others [OK]

Common Mistakes:

• Assuming data copies across column families
• Thinking all families must have data per row
• Believing row is deleted if some families are empty

4. You tried to create an HBase table with this command: create 'mytable' 'cf1' 'cf2' but got an error. What is the likely cause?

medium

A. You cannot create multiple column families in one command

B. The syntax requires column families as separate arguments with commas

C. Column family names must be enclosed in double quotes

D. Table names cannot contain numbers

Solution

1. Step 1: Review HBase create table syntax

   The correct syntax is: create 'table_name', 'cf1', 'cf2' with commas between column families.

2. Step 2: Identify the error in the command

   The command is missing commas between column families, which is invalid syntax in HBase shell.

3. Final Answer:

   The syntax requires column families as separate arguments with commas -> Option B

4. Quick Check:

   HBase create syntax = with commas between column families [OK]

Hint: List column families with commas in create command [OK]

Common Mistakes:

• Omitting commas between column families
• Using quotes incorrectly
• Thinking table names can't have numbers

5. You want to design an HBase table to store customer data with addresses and orders. Which is the best way to use column families?

hard

A. Create one column family for all data: 'cf_all'

B. Create a column family per customer

C. Create separate column families like 'address' and 'orders' to group related columns

D. Store addresses as rows and orders as columns in one family

Solution

1. Step 1: Understand column family design principles

   Column families group related columns to improve performance and reflect real-world categories.

2. Step 2: Apply to customer data scenario

   Separating 'address' and 'orders' into different column families groups related data logically and optimizes storage.

3. Final Answer:

   Create separate column families like 'address' and 'orders' to group related columns -> Option C

4. Quick Check:

   Use column families to group related data categories [OK]

Hint: Group related data in separate column families for clarity [OK]

Common Mistakes:

• Putting all data in one family causing inefficiency
• Creating a family per customer wastes resources
• Mixing rows and columns incorrectly