❖ UniqueBridgeTable

❖ 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.

Use the UniqueBridgeTable constraint when you have a bridge table that records a many-to-many relationship between multiple tables, and the connections have to be unique. That is to say, the combinations of keys in the bridge tables must be unique.

This constraint is deprecated. Instead of supplying a UniqueBridgeTable constraint, represesent the bridge table as a composite key in your metadata. For more information, see the Metadata API.

{
    "tables": {
        "Authors": {
            "primary_key": "ID",
            ...
        },
        "Books": {
            "primary_key": "ID",
            ...
        },
        "Author-Book": {
            "primary_key": ["Author ID", "Book ID"],
            ...
        }
    },
    "relationships": [{
        "parent_table_name": "Authors",
        "parent_primary_key": "ID",
        "child_table_name": "Author-Book",
        "child_foreign_key": "Author ID",
    },{
        "parent_table_name": "Books",
        "parent_primary_key": "ID",
        "child_table_name": "Author-Book",
        "child_foreign_key": "Book ID", 
    }]   
}

The Author-Book table records unique links between Authors and Books.

Constraint API

Create a UniqueBridgeTable constraint.

Parameters:

• (required) table_name: A string with the name of the bridge table

• (required) foreign_key_columns: A list of strings with the names of the foreign key columns. The combination of values in these columns must be unique.

from sdv.cag import UniqueBridgeTable

my_constraint = UniqueBridgeTable(
    table_name='Author-Book',
    foreign_key_columns=['Author ID', 'Book ID'])

Make sure that all the tables and columns you provide are listed in your Metadata, as well as all foreign key connections.

Usage

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

synthesizer = HSASynthesizer(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.