# ❖ ChainedInequality

{% hint style="info" %}
❖ **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](https://docs.sdv.dev/sdv/explore/sdv-bundles/cag) page.
{% endhint %}

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.

```python
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.

```python
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**](https://colab.research.google.com/drive/1WCMQujfVKL5giULZXOPPIBoMfzR9Zj68?usp=sharing).

## 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.

```python
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).

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