Snowflake Scripting 101: Blocks in Snowflake Scripting

Harness the full potential of Snowflake scripting to streamline data operations and automate complex business logics. Dive into this practical guide to discover how scripting blocks transform your Snowflake scripting experience, enabling:

Precise control over data flows
Optimized conditional logic
Efficient looping structures
Custom error handling
And more!

Page Content

Understanding Blocks

Structure of Block in a Snowflake Scripting

Types of Blocks in Snowflake Scripting

Common Block Use Cases

Advanced Block Techniques

Conclusion

Understanding Blocks in Snowflake Scripting

In Snowflake Scripting, blocks serve as essential building blocks for organizing and executing procedural code. Similar to other database programming language, blocks are defined using specific keywords to structure your code into different sections, each with a clear purpose.

Structure of Block in a Snowflake Scripting

Snowflake scripting block has the following basic structure:

DECLARE
  ... variable declarations, ... 
  ... cursor declarations, etc ...
BEGIN
  ... Snowflake Scripting and SQL statements ...
EXCEPTION
  ... statements for handling exceptions ...
END;

Here’s a breakdown of the key components of a block:

DECLARE: This optional section is where you declare variables, cursors, result sets, and custom exceptions that will be used within the block.
BEGIN…END: This mandatory section is the main body of your procedural code. It’s where you’ll write SQL statements, control flow structures (like loops and conditionals), and other procedural logic.
EXCEPTION: This optional section is allows you to handling errors that may arise during code execution. It allows you to efficiently trap exceptions and perform appropriate actions to address them.

By effectively utilizing blocks, you can achieve the following:

Structured Code: Organize your code into different logical groups, making it easier to read, understand, and maintain.
Control Flow: Implement conditional logic and looping structures to handle different scenarios and automate repetitive tasks.
Error Handling: Gracefully handle potential errors and prevent your script from failing unexpectedly.
Modularization: Break down complex tasks into smaller, reusable blocks to enhance code reusability and maintainability.

Types of Blocks in Snowflake Scripting

Within Snowflake Scripting, blocks come in two different forms, each designed for specific use cases

Stored Procedure Blocks
Anonymous Block

Stored Procedure Blocks

A stored procedure serves as a container for encapsulating business logic, capable of managing complex operations like branching and looping structures, return results, gracefully handle errors, and even create dynamic SQL statements within stored procedures.

The Snowflake scripting stored procedure comprises distinct sections, including DECLARE, BEGIN, EXCEPTION, and END, organizing the code’s structure and functionality.

The following is an example that uses various blocks:

create or replace procedure procedure_blocks()
  returns float
  language sql
  as
    declare
      radius float;
      area_of_circle float;
    begin
      radius := 3;
      area_of_circle := pi() * radius * radius;
      return area_of_circle;
  exception
  when other then
    return object_construct('Error type', 'Other error',
                            'SQLCODE', sqlcode,
                            'SQLERRM', sqlerrm,
                            'SQLSTATE', sqlstate);
    end;

Anonymous Blocks in Snowflake Script

In Snowflake Scripting, anonymous blocks offer a flexible means to execute procedural code without the need to create a formal stored procedure. They reside outside the confines of stored procedures, providing a distinct execution model.

Anonymous blocks are defined as self-contained SQL statements, allowing you to execute them directly within a session or script. Unlike stored procedures, they aren’t persistently stored in the database. Instead, they exist only for the duration of the session or script in which they’re executed.

The following is an example of an anonymous block:

declare
  radius_of_circle float;
  area_of_circle float;
begin
  radius_of_circle := 3;
  area_of_circle := pi() * radius_of_circle * radius_of_circle;
  return area_of_circle;
exception
  when other then
    return object_construct('Error type', 'Other error',
                            'SQLCODE', sqlcode,
                            'SQLERRM', sqlerrm,
                            'SQLSTATE', sqlstate);  
end;

The BEGIN and END block that defines the block will also executes the block. You don’t have to call separate CALL statement to execute this block.

Common Snowflake Block Use Cases

Following are some of the Snowflake script block use cases:

Data Manipulation:
- Creating tables and loading data using DDL statements within blocks.
- Updating and deleting data with conditional checks inside blocks.
Branching Logic:
- Using loops and cursors for iterating through result sets.
- Controlling flow with IF and CASE statements within blocks.
- Handling different scenarios based on conditions.
Error Handling:
- Using the EXCEPTION block to trap and handle errors easily.
- Logging error messages and taking corrective actions within blocks.

Advanced Snowflake Block Use Cases

Following are the advance use cases of Snowflake scripting blocks:

Return Resultset:
- Returning values from blocks using the RETURN statement.
- Return result set in the form of table.
- Use stored procedure and user-defined functions within the Snowflake scripting blocks.

Conclusion

In conclusion, Snowflake scripting Stored procedures blocks are ideal for complex, reusable logic, offering organization and persistence. and Snowflake scripting anonymous blocks are perfect for on-demand execution, testing, and one-time tasks, prioritizing flexibility.