Snowflake COF-C02 Practice Test - Questions Answers, Page 64

To minimize Continuous Data Protection (CDP) costs when dealing with large, high-churn dimension tables in Snowflake, using transient tables is a recommended approach.

Transient Tables: These are designed for data that does not require fail-safe protection. They provide the benefit of reducing costs associated with continuous data protection since they do not have the seven-day Fail-safe period that is mandatory for permanent tables.

Periodic Copying to Permanent Tables: By periodically copying data from transient tables to permanent tables, you can achieve a balance between data protection and cost-efficiency. Permanent tables offer the extended data protection features, including Time Travel and Fail-safe, but these features can be applied selectively rather than continuously, reducing the overall CDP costs.

References:

Snowflake Documentation on Transient Tables

Snowflake Documentation on Time Travel & Fail-safe

To convert semi-structured data into rows and columns in Snowflake, the FLATTEN function is utilized.

FLATTEN Function: This function takes semi-structured data (e.g., JSON) and transforms it into a relational table format by breaking down nested structures into individual rows. This process is essential for querying and analyzing semi-structured data using standard SQL operations.

Example Usage:

SELECT

f.value:attribute1 AS attribute1,

f.value:attribute2 AS attribute2

FROM

my_table,

LATERAL FLATTEN(input => my_table.semi_structured_column) f;

References:

Snowflake Documentation on FLATTEN

Snowflake utilizes clustering information to enhance query performance by pruning unnecessary micro-partitions.

Clustering Metadata: Snowflake stores clustering information for each micro-partition, which includes data range and distribution.

Pruning Micro-partitions: When a query is executed, Snowflake uses this clustering metadata to identify and eliminate micro-partitions that do not match the query criteria, thereby reducing the amount of data scanned and improving query performance.

References:

Snowflake Documentation on Clustering

Snowflake Documentation on Micro-partition Pruning

To remove staged files during data loading after they have been successfully loaded, the PURGE copy option is used in Snowflake.

PURGE Option: This option automatically deletes files from the stage after they have been successfully copied into the target table.

Usage:

FROM @my_stage

FILE_FORMAT = (type = 'csv')

PURGE = TRUE;

References:

Snowflake Documentation on COPY INTO

The function used to determine the kind of value stored in a VARIANT column in Snowflake is TYPEOF.

Understanding VARIANT Data Type:

VARIANT is a flexible data type in Snowflake that can store semi-structured data, such as JSON, Avro, and XML.

This data type can hold values of different types, including strings, numbers, objects, arrays, and more.

Using TYPEOF Function:

The TYPEOF function returns the data type of the value stored in a VARIANT column.

It helps in identifying the type of data, which is crucial for processing and transforming semi-structured data accurately.

Example Usage:

SELECT TYPEOF(variant_column)

FROM my_table;

This query retrieves the type of data stored in variant_column for each row in my_table.

Possible return values include 'OBJECT', 'ARRAY', 'STRING', 'NUMBER', etc.

Benefits:

Simplifies data processing: Knowing the data type helps in applying appropriate transformations and validations.

Enhances query accuracy: Ensures that operations on VARIANT columns are performed correctly based on the data type.

References:

Snowflake Documentation: TYPEOF

Snowflake Documentation: VARIANT Data Type

In Snowflake, a role is an access control entity that can be created as part of a hierarchy within an account. Roles are used to grant and manage privileges in a structured and scalable manner.

Understanding Roles:

Roles are logical entities that group privileges together.

They are used to control access to securable objects like tables, views, warehouses, and more.

Role Hierarchy:

Roles can be organized into a hierarchy, allowing for the inheritance of privileges.

A role higher in the hierarchy (parent role) can grant its privileges to a lower role (child role), simplifying privilege management.

Creating Roles:

Roles can be created using the CREATE ROLE command.

You can define parent-child relationships by granting one role to another.

Example Usage:

CREATE ROLE role1;

CREATE ROLE role2;

GRANT ROLE role1 TO role2;

In this example, role2 inherits the privileges of role1.

Benefits:

Simplifies privilege management: Hierarchies allow for efficient privilege assignment and inheritance.

Enhances security: Roles provide a clear structure for managing access control, ensuring that privileges are granted appropriately.

References:

Snowflake Documentation: Access Control in Snowflake

Snowflake Documentation: Creating and Managing Roles

In Snowflake, when an object is created, it is owned by the role that is currently active. This active role is the one that is being used to execute the creation command. Ownership implies full control over the object, including the ability to grant and revoke access privileges. This is specified in Snowflake's documentation under the topic of Access Control, which states that 'the role in use at the time of object creation becomes the owner of the object.'

References:

Snowflake Documentation: Object Ownership

The ACCESS_HISTORY view in Snowflake provides detailed information about queries executed in the account, including metadata such as the time of execution, the user, and the SQL text of the queries. This view is available in the Snowflake Enterprise edition and higher editions. The Standard edition does not include this feature.

References:

Snowflake Documentation: Access History

Snowflake Editions: Snowflake Pricing

The ORGADMIN role in Snowflake is responsible for managing organization-level administrative functions, which include managing billing and credit data. This role has the highest level of administrative privileges and can oversee multiple Snowflake accounts within an organization.

References:

Snowflake Documentation: Account and Organization Roles