Returns column data following db.Column parameter specification.

def get_column_metadata(conn, table: str, schema='public'):
    """Returns column data following db.Column parameter specification."""
    query = """\
SELECT
  attname as name,
  format_type(atttypid, atttypmod) AS data_type,
  NOT attnotnull AS nullable
FROM pg_catalog.pg_attribute
WHERE attrelid=%s::regclass
  AND attnum > 0 AND NOT attisdropped
ORDER BY attnum;"""

    qualified_name = compile_qualified_name(table, schema=schema)

    for record in select_dict(conn, query, params=(qualified_name,)):
        yield record