UNIQUE constraints not reflecting

[wpfl-dbt]

Currently, live tables are reflected, then checked column by column for identity based on several pieces of data, including Column.unique.

pg-bulk-ingest/pg_bulk_ingest/__init__.py

Lines 139 to 146 in 41bb283

	columns_target = tuple(
	(col.name, repr(col.type), col.nullable, col.primary_key, col.unique) for col in target_table.columns.values()
	)
	columns_live = tuple(
	(col.name, repr(col.type), col.nullable, col.primary_key, col.unique) for col in live_table.columns.values()
	)
	must_create_ingest_table = indexes_target_repr != indexes_live_repr or columns_target != columns_live

The problem is that reflected tables store the unique constraint under Table.constraints, not in the Table.column Column objects. When reflecting a table, Column.unique will always be None.

This means that this ingested table definition will trigger a swap:

sa.Table(
    "foo",
    sa.Column("bar", sa.VARCHAR(10), unique=True),
)

But this won't:

sa.Table(
    "foo",
    sa.Column("bar", sa.VARCHAR(10)),
    sa.UniqueConstraint("bar"),
)

Even though they're functionally identical.