Data classification and tagging in Snowflake - Mini Project: Build & Apply

Data Classification and Tagging in Snowflake

📖 Scenario: You work as a data engineer in a company that uses Snowflake to store data. Your team wants to organize data better by classifying tables and tagging them with important labels like 'PII' (personally identifiable information) or 'Finance'. This helps everyone find and protect sensitive data easily.

🎯 Goal: Build a Snowflake setup where you create a table, define classification tags, and assign those tags to the table to mark its data type.

📋 What You'll Learn

Create a table named customer_data with columns id (integer) and email (string).

Create a tag named data_classification with allowed values 'PII' and 'Non-PII'.

Assign the tag data_classification with value 'PII' to the customer_data table.

💡 Why This Matters

🌍 Real World

Classifying and tagging data helps companies manage sensitive information securely and comply with regulations.

💼 Career

Data engineers and cloud architects often organize data with tags to improve data governance and security.

1

Create the customer_data table

Write a Snowflake SQL statement to create a table called customer_data with two columns: id as INTEGER and email as STRING.

Snowflake

-- Your code here to create the customer_data table

Hint

Use CREATE TABLE followed by the table name and column definitions inside parentheses.

2

Create the data_classification tag

Write a Snowflake SQL statement to create a tag called data_classification with allowed values 'PII' and 'Non-PII'.

Snowflake

-- Your code here to create the data_classification tag

Hint

Use CREATE TAG with ALLOWED_VALUES to specify the possible tag values.

3

Assign the data_classification tag to the customer_data table

Write a Snowflake SQL statement to assign the tag data_classification with value 'PII' to the customer_data table.

Snowflake

CREATE TABLE customer_data (id INTEGER, email STRING);
CREATE TAG data_classification ALLOWED_VALUES = ('PII', 'Non-PII');
-- Your code here to assign the tag to the table

Hint

Use ALTER TABLE with SET TAG to assign the tag value.

4

Verify the tag assignment

Write a Snowflake SQL query to show the tags assigned to the customer_data table.

Snowflake

CREATE TABLE customer_data (id INTEGER, email STRING);
CREATE TAG data_classification ALLOWED_VALUES = ('PII', 'Non-PII');
ALTER TABLE customer_data SET TAG data_classification = 'PII';
-- Your code here to show tags on the customer_data table

Hint

Use SHOW TAGS ON TABLE followed by the table name to see assigned tags.

Practice

1. What is the main purpose of data classification and tagging in Snowflake?

easy

A. To speed up query performance by indexing data

B. To convert data into different file formats

C. To automatically delete old data after a set time

D. To organize and protect data by labeling it with tags

Solution

1. Step 1: Understand data classification and tagging

   Data classification and tagging help label data to organize and protect it.

2. Step 2: Identify the purpose in Snowflake context

   Tags are used to mark data for governance and security, not for performance or deletion.

3. Final Answer:

   To organize and protect data by labeling it with tags -> Option D

4. Quick Check:

   Data classification = Organize and protect data [OK]

Hint: Tags label data to organize and protect it [OK]

Common Mistakes:

• Confusing tagging with indexing for performance
• Thinking tags delete data automatically
• Assuming tags change data format

2. Which of the following is the correct syntax to create a tag in Snowflake?

easy

A. CREATE TAG tag_name COMMENT = 'description';

B. CREATE TAG tag_name WITH 'description';

C. MAKE TAG tag_name COMMENT 'description';

D. NEW TAG tag_name SET COMMENT = 'description';

Solution

1. Step 1: Recall Snowflake tag creation syntax

   The correct syntax uses CREATE TAG followed by the tag name and COMMENT clause.

2. Step 2: Compare options with syntax

   Only CREATE TAG tag_name COMMENT = 'description'; matches the correct syntax: CREATE TAG tag_name COMMENT = 'description';

3. Final Answer:

   CREATE TAG tag_name COMMENT = 'description'; -> Option A

4. Quick Check:

   CREATE TAG ... COMMENT = ... is correct syntax [OK]

Hint: Use CREATE TAG with COMMENT = 'text' [OK]

Common Mistakes:

• Using MAKE or NEW instead of CREATE
• Missing equal sign in COMMENT clause
• Using WITH instead of COMMENT

3. Given the following commands, what will be the result of querying the tags on the customers table?

CREATE TAG pii COMMENT = 'Personally Identifiable Information';
ALTER TABLE customers SET TAG pii = 'true';
SHOW TAGS ON TABLE customers;

medium

A. It will show the tag 'pii' with value 'true' assigned to the customers table

B. It will show an error because tags cannot be set on tables

C. It will show the tag 'pii' but with no value assigned

D. It will show no tags because SHOW TAGS is invalid syntax

Solution

1. Step 1: Understand tag creation and assignment

   The tag 'pii' is created and then assigned to the 'customers' table with value 'true'.

2. Step 2: Check SHOW TAGS syntax and output

   SHOW TAGS ON TABLE customers; lists tags assigned to the table, showing 'pii' = 'true'.

3. Final Answer:

   It will show the tag 'pii' with value 'true' assigned to the customers table -> Option A

4. Quick Check:

   SHOW TAGS ON TABLE shows assigned tags [OK]

Hint: SHOW TAGS ON TABLE lists assigned tags and values [OK]

Common Mistakes:

• Thinking tags cannot be assigned to tables
• Assuming SHOW TAGS syntax is invalid
• Expecting tags without values to appear

4. You run the following command but get an error:

ALTER TABLE orders SET TAG sensitive = 'yes';

What is the most likely cause of the error?

medium

A. ALTER TABLE cannot be used to set tags

B. The value 'yes' is not allowed for tags

C. The tag 'sensitive' was not created before assigning it

D. Tags can only be assigned to columns, not tables

Solution

1. Step 1: Check if tag exists before assignment

   Tags must be created with CREATE TAG before assigning to tables or columns.

2. Step 2: Analyze error cause

   If 'sensitive' tag was not created, assigning it causes an error.

3. Final Answer:

   The tag 'sensitive' was not created before assigning it -> Option C

4. Quick Check:

   Tags must exist before assignment [OK]

Hint: Create tags before assigning them [OK]

Common Mistakes:

• Assuming any value is invalid
• Thinking ALTER TABLE can't set tags
• Believing tags only apply to columns

5. You want to classify columns in a payments table as either 'confidential' or 'public' using tags. Which approach correctly applies tags to columns and supports data governance?

hard

A. Create tags and assign them to database schemas instead of columns

B. Create tags 'confidential' and 'public', then assign them to each column with ALTER TABLE ... ALTER COLUMN ... SET TAG

C. Use column comments instead of tags to classify data sensitivity

D. Create tags and assign them only to the table, not columns, to simplify management

Solution

1. Step 1: Understand tagging granularity

   Tags can be assigned to columns to classify data precisely, supporting governance.

2. Step 2: Identify correct tagging method

   Using ALTER TABLE ... ALTER COLUMN ... SET TAG applies tags to columns, enabling classification.

3. Final Answer:

   Create tags 'confidential' and 'public', then assign them to each column with ALTER TABLE ... ALTER COLUMN ... SET TAG -> Option B

4. Quick Check:

   Column-level tags enable precise data classification [OK]

Hint: Tag columns directly for precise classification [OK]

Common Mistakes:

• Tagging only tables loses column-level detail
• Using comments instead of tags for governance
• Assigning tags to schemas instead of columns