COF-C02 Exam Dumps - SnowPro Core Certification Exam

Snowflake Streams are used to track and record Data Manipulation Language (DML) changes made to a table. Streams capture changes such as inserts, updates, and deletes, which can then be processed by other Snowflake objects or external applications.

Creating a Stream:

CREATE OR REPLACE STREAM my_stream ON TABLE my_table;

Using Streams: Streams provide a way to process changes incrementally, making it easier to build efficient data pipelines.

Consuming Stream Data: The captured changes can be consumed using SQL queries or Snowflake tasks.

References:

Snowflake Documentation: Using Streams

Snowflake Documentation: Change Data Capture (CDC) with Streams

Snowflake supports a variety of subquery types, including both correlated and uncorrelated subqueries. The correct answers are B and E, which highlight Snowflake's flexibility in handling subqueries within SQL queries.

Uncorrelated Scalar Subqueries: These are subqueries that can execute independently of the outer query. They return a single value and can be used anywhere a value expression is allowed, offering great flexibility in SQL queries.

EXISTS, ANY/ALL, and IN Subqueries: These subqueries are used in WHERE clauses to filter the results of the main query based on the presence or absence of matching rows in a subquery. Snowflake supports both correlated and uncorrelated versions of these subqueries, providing powerful tools for complex data analysis scenarios.

Examples and Usage:

Uncorrelated Scalar Subquery:

SELECT * FROM employees WHERE salary > (SELECT AVG(salary) FROM employees);

Correlated EXISTS Subquery:

SELECT * FROM orders o WHERE EXISTS (SELECT 1 FROM customer c WHERE c.id = o.customer_id AND c.region = 'North America');

When sharing data in Snowflake, the provider needs to grant the following privileges along with a share:

A. USAGE on the specific tables in the database: This privilege allows the consumers of the share to access the specific tables included in the share.

D. USAGE on the database and the schema containing the tables to share: This privilege is necessary for the consumers to access the database and schema levels, enabling them to access the tables within those schemas.

These privileges are crucial for setting up secure and controlled access to the shared data, ensuring that only authorized users can access the specified resources.

Reference to Snowflake documentation on sharing data and managing access:

Data Sharing Overview

Privileges Required for Sharing Data

The GET_PRESIGNED_URL function in Snowflake generates a pre-signed URL for a file in an internal stage. This URL can be shared with external tools or users who do not have direct access to Snowflake, allowing them to download the file.

Generate Pre-Signed URL:

SELECT GET_PRESIGNED_URL(@my_stage/file.txt);

Share the URL: The generated URL can be shared with external users or applications, enabling them to access the file directly.

References:

Snowflake Documentation: GET_PRESIGNED_URL

Snowflake Documentation: Working with Stages

In Snowflake, reader accounts are special types of accounts that allow data sharing with external consumers without them having their own Snowflake account. The creation and management of reader accounts can be performed by users with the ACCOUNTADMIN role or the ORGADMIN role. The ACCOUNTADMIN role has comprehensive administrative privileges within a Snowflake account, including managing other accounts and roles. The ORGADMIN role, which is higher in hierarchy, oversees multiple accounts within an organization and can manage reader accounts across those accounts.

References:

Snowflake Documentation: Creating and Managing Reader Accounts

Snowflake's governance features vary across different editions, but the OBJECT_DEPENDENCIES view is supported by all Snowflake editions. This feature is part of Snowflake's Information Schema and is designed to help users understand the dependencies between various objects in their Snowflake environment.

The OBJECT_DEPENDENCIES view provides a way to query and analyze the relationships and dependencies among different database objects, such as tables, views, and stored procedures. This is crucial for governance, as it allows administrators and data engineers to assess the impact of changes, understand object relationships, and ensure proper management of data assets.

Object tags, masking policies, and row access policies are more advanced features that offer fine-grained data governance capabilities such as tagging objects for classification, dynamically masking sensitive data based on user roles, and controlling row-level access to data. These features may have varying levels of support across different Snowflake editions, with some features being exclusive to higher-tier editions.

In Snowflake, a Temporary table is a type of table that is only visible to the user who creates it, can have the same name as permanent tables in the same schema, and is automatically dropped at the end of the session in which it was created. Temporary tables are designed for transient data processing needs, where data is needed for the duration of a specific task or session but not beyond. Since they are automatically cleaned up at the end of the session, they help manage storage usage efficiently and ensure that sensitive data is not inadvertently persisted.

References:

Snowflake Documentation on Temporary Tables: Temporary Tables

The command used to export or unload data from Snowflake to a stage (such as a file in an S3 bucket, Azure Blob Storage, or Google Cloud Storage) is the PUT command. The PUT command is designed to upload data files from a local file system (in the case of SnowSQL or other client) or a virtual warehouse to a specified stage. This functionality is critical for scenarios where data needs to be extracted from Snowflake for use in external systems, backups, or further processing.

The syntax for the PUT command follows the structure: PUT file://<local_file_path> @<stage_name>, where <local_file_path> specifies the path to the file(s) on the local file system that you wish to upload, and <stage_name> specifies the destination stage in Snowflake.

It's important to distinguish that the PUT command is used for exporting data out of Snowflake, whereas the COPY INTO <table> command is used for importing data into Snowflake from a stage. The GET command, on the other hand, is used to download files from a stage to the local file system, essentially the inverse operation of the PUT command.

References:

Snowflake Documentation on Loading and Unloading Data: [Loading and Unloading Data](https://docs.snowflake.com/en/user-guide/data-load