❖ ChainedInequality

❖ SDV Enterprise Bundle. This feature is available as part of the CAG Bundle, an optional add-on to SDV Enterprise. For more information, please visit the CAG Bundle page.

The ChainedInequality constraint enforces a chain of inequality relationships between any number of columns. For every row, the value in these columns must follow a strict ordering system.

Constraint API

Create a ChainedInequality constraint.

Parameters:

• (required) column_names: A list of strings that represent the column names. They should appear in ascending order (lowest to highest). Only numerical and datetime columns are allowed.

• strict_boundaries: Whether a column must be strictly greater than previous one

  • (default) True: The value in the higher column must be strictly greater than the lower one

  • False: The value in the higher column must be greater than or equal to the value of the lower one

• table_name: A string with the name of the table to apply this to. Required if you have a multi-table dataset.

from sdv.cag import ChainedInequality

my_constraint = ChainedInequality(
    column_names=['purchase_date', 'start_date', 'end_date', 'expiration_date']
)   

Usage

Apply the constraint to any SDV synthesizer. Then fit and sample as usual.

synthesizer = GaussianCopulaSynthesizer(metadata)
synthesizer.add_constraints([my_constraint])

synthesizer.fit(data)
synthetic_data = synthesizer.sample()

For more information about using predefined constraints, please see the Constraint-Augmented Generation tutorial.

Auto-Detection

Auto-detection is allowed for this constraint and it is enabled by default. Run the detection with your data to detect all instances of this constraint throughout the dataset.

constraints = synthesizer.detect_constraints(data)

Detection Parameters: By default, SDV detects this constraint for datetime columns only. Use the the sdtypes parameter to update this. Provide a list of sdtypes to detect (datetime, numerical, or both).

constraints = synthesizer.detect_constraints(
    data,
    constraint_classes=['ChainedInequality'],
    detection_params={
        'ChainedInequality': { 'sdtypes': [ 'numerical', 'datetime' ] }
    }
)