Combining column relationship with constraints not working

[sarahmish]

Environment Details

Please indicate the following details about the environment in which you found the bug:

• SDV version: 1.31.0
• Python version: 3.10.19
• Operating System: macos 14.6.1

Error Description

If my metadata has column relationship, and I am trying to add the FixedCombinations constraint to my synthesizer, I get the following error:

AttributeError: 'SingleTableMetadata' object has no attribute '_valid_column_relationships'

I expect that I should be able to combine the column relationship with the constraint especially that no columns overlap between them.

Steps to reproduce

from sdv.metadata import Metadata
from sdv.multi_table import HMASynthesizer
from sdv.cag import FixedCombinations

metadata_example = Metadata.load_from_dict({
    'tables': {
        'table': {
            'columns': {
                'id': {'sdtype': 'id'},
                'street': {'sdtype': 'street_address'},
                'city': {'sdtype': 'city'},
                'state': {'sdtype': 'administrative_unit'},
                'zip': {'sdtype': 'postcode'},
                'code': {'sdtype': 'categorical'},
                'description': {'sdtype': 'categorical'}
            }
        },
        'table_two': {
            'columns': {
                'id': {'sdtype': 'id'},
            }
        }
    }
})

metadata_example.add_column_relationship(
    table_name='table', relationship_type='address',
    column_names=['street', 'city', 'state', 'zip']
)

synthesizer = HMASynthesizer(metadata_example, locales=['en_US'])
constraints = FixedCombinations(table_name='table', column_names=['code', 'description'])
synthesizer.add_constraints(constraints=[constraints])