09-constant-examples.mdl

-- ############################################################################
-- CONSTANT EXAMPLES
-- ############################################################################
--
-- This file demonstrates the MDL syntax for managing constants.
-- Constants are module-level values that can be configured per environment.
--
-- Prerequisites: Assumes a module 'CoTest' exists.
--
-- ############################################################################

create module CoTest;

-- MARK: - Create Constants

/**
 * Level 1.1: Create a string constant
 * String constants are useful for configuration values like URLs and API keys.
 */
CREATE CONSTANT CoTest.ServiceEndpoint
TYPE String
DEFAULT 'https://api.example.com/v1';
/

/**
 * Level 1.2: Create a string constant with a comment
 * Comments help explain the purpose and expected values.
 */
CREATE CONSTANT CoTest.ApiKey
TYPE String
DEFAULT ''
COMMENT 'API key for external service. Configure per environment.';
/

/**
 * Level 1.3: Create an integer constant
 * Integer constants are useful for configuration like timeouts and limits.
 */
CREATE CONSTANT CoTest.MaxRetries
TYPE Integer
DEFAULT 3;
/

/**
 * Level 1.4: Create a long constant
 * Long constants support larger numeric values.
 */
CREATE CONSTANT CoTest.MaxFileSize
TYPE Long
DEFAULT 10485760
COMMENT 'Maximum file upload size in bytes (default 10MB)';
/

/**
 * Level 1.5: Create a decimal constant
 * Decimal constants are useful for precise numeric values like rates.
 */
CREATE CONSTANT CoTest.TaxRate
TYPE Decimal
DEFAULT 0.21
COMMENT 'Default tax rate (21%)';
/

/**
 * Level 1.6: Create a boolean constant
 * Boolean constants are useful for feature flags.
 */
CREATE CONSTANT CoTest.EnableDebugLogging
TYPE Boolean
DEFAULT false
COMMENT 'Enable verbose debug logging';
/

/**
 * Level 1.7: Create a DateTime constant
 * DateTime constants for default timestamps.
 */
CREATE CONSTANT CoTest.LaunchDate
TYPE DateTime
DEFAULT '[%BeginOfCurrentDay%]';
/

-- MARK: - Show Constants

/**
 * Level 2.1: Show all constants in the project
 * Lists all constants across all modules with their types and default values.
 */
SHOW CONSTANTS;
/

/**
 * Level 2.2: Show constants in a specific module
 * Lists only constants defined in the specified module.
 */
SHOW CONSTANTS IN CoTest;
/

/**
 * Level 2.3: Show constant values across all configurations
 * Displays one row per constant per configuration for easy comparison.
 */
SHOW CONSTANT VALUES;
/

/**
 * Level 2.4: Show constant values for a specific module
 */
SHOW CONSTANT VALUES IN CoTest;
/

-- MARK: - Describe Constant

/**
 * Level 3.1: Describe a constant
 * Shows the full definition of a constant including its type and default value.
 */
DESCRIBE CONSTANT CoTest.ServiceEndpoint;
/

-- MARK: - Create Or Modify Constants

/**
 * Level 3.2: Create or modify a constant (upsert)
 * Creates the constant if it does not exist, or updates it if it does.
 * Use this when you want to ensure a constant has a specific value
 * regardless of whether it was previously created.
 */
CREATE OR MODIFY CONSTANT CoTest.ServiceEndpoint
TYPE String
DEFAULT 'https://api.staging.example.com/v2'
COMMENT 'Updated endpoint for staging environment';
/

/**
 * Level 3.3: Create or modify a boolean constant
 * Useful for toggling feature flags idempotently in scripts.
 */
CREATE OR MODIFY CONSTANT CoTest.EnableDebugLogging
TYPE Boolean
DEFAULT true;
/

-- MARK: - Drop Constants

/**
 * Level 4.1: Drop a constant
 * Removes a constant from the module.
 */
DROP CONSTANT CoTest.LaunchDate;
/

-- MARK: - Constants in Microflow Expressions (regression: issue #178)

/**
 * Level 5.1: Use @Module.Const in a microflow DECLARE
 * Tests that `@Module.Const` syntax parses and round-trips correctly.
 * Regression test for: DESCRIBE → re-parse roundtrip with @-style constant refs.
 */
CREATE OR REPLACE MICROFLOW CoTest.UseConstantRef ()
RETURNS Nothing
BEGIN
  DECLARE $Endpoint String = @CoTest.ServiceEndpoint;
  DECLARE $Retries Integer = @CoTest.MaxRetries;
  DECLARE $IsTaxable Boolean = @CoTest.EnableDebugLogging;
END;
/

/**
 * Level 5.2: Mix @Module.Const with other expressions
 * Confirms constant references work in compound expressions alongside literals.
 */
CREATE OR REPLACE MICROFLOW CoTest.MixedConstantExpressions ()
RETURNS Nothing
BEGIN
  DECLARE $Limit Decimal = @CoTest.TaxRate + 0.05;
  DECLARE $Msg String = 'Endpoint: ' + @CoTest.ServiceEndpoint;
END;
/

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-- END OF CONSTANT EXAMPLES
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