To find information about query activity from 90 days ago, a Snowflake user should use the account_usage.query_history_archive view. This view is designed to provide access to historical query data beyond the default 14-day retention period found in the standard query_history view. It allows users to analyze and audit past query activities for up to 365 days after the date of execution, which includes the 90-day period mentioned.

References:

[COF-C02] SnowPro Core Certification Exam Study Guide

Snowflake Documentation on Account Usage Schema1

A Snowflake user would decide to use a materialized view instead of a regular view primarily when the base tables do not change frequently. Materialized views store the result of the view query and update it as the underlying data changes, making them ideal for situations where the data is relatively static and query performance is critical. By precomputing and storing the query results, materialized views can significantly reduce query execution times for complex aggregations, joins, and calculations.

References:

Snowflake Documentation: Materialized Views

 Snowflake’s default Multi-Factor Authentication (MFA) service is powered by Duo Security. Users are required to install the Duo Mobile application on their devices to use MFA for increased login security when connecting to Snowflake. This service is managed entirely by Snowflake, and users do not need to sign up separately with Duo1.

Assigning the custom role to the SYSADMIN role is considered a best practice because it allows the SYSADMIN role to manage objects created by the custom role. This is important for maintaining proper access control and ensuring that the SYSADMIN can perform necessary administrative tasks on objects created by users with the custom role.

References:

[COF-C02] SnowPro Core Certification Exam Study Guide

Section 1.3 - SnowPro Core Certification Study Guide1

The COPY command in Snowflake allows for the reordering of columns as they are loaded into a table, and it also permits the omission of columns from the source file during the load process. This provides flexibility in handling the schema of the data being ingested. References: [COF-C02] SnowPro Core Certification Exam Study Guide

The VARIANT data type in Snowflake is used to store JSON key-value pairs along with other semi-structured data formats like AVRO, BSON, and XML. The VARIANT data type allows for flexible and dynamic data structures within a single column, accommodating complex and nested data. This data type is crucial for handling semi-structured data in Snowflake, enabling users to perform SQL operations on JSON objects and arrays directly.

References:

Snowflake Documentation: Semi-structured Data Types

A Pre-signed URL provides access to files stored in Snowflake without requiring authorization at the time of access. This feature allows users to generate a URL with a limited validity period that grants temporary access to a file in a secure manner. It's particularly useful for sharing data with external parties or applications without the need for them to authenticate directly with Snowflake.

References:

Snowflake Documentation: Using Pre-signed URLs

Purpose: The BUILD_STAGE_FILE_URL function generates a temporary, pre-signed URL that allows you to access a file within a Snowflake stage (internal or external). This URL requires authentication to use.

Key Points:

Security: The URL has a limited lifespan, enhancing security.

Use Cases: Sharing staged data with external tools or applications, or downloading it directly.

Snowflake Documentation (BUILD_STAGE_FILE_URL): https://docs.snowflake.com/en/sql-reference/functions/build_stage_file_url.html

When creating a CSV file format in Snowflake and the requirement is to wrap columns by single quotes or double quotes, the FIELD_OPTIONALLY_ENCLOSED_BY parameter should be used in the file format specification. This parameter allows you to define a character (either a single quote or a double quote) that can optionally enclose each field in the CSV file, providing flexibility in handling fields that contain special characters or delimiters as part of their data.

References:

Snowflake Documentation: CSV File Format

The Snowflake command to unload the result of a query to a single file is COPY INTO with SINGLE = TRUE followed by a GET command to download the file. This command unloads the query result into a single file in the specified internal stage