def get_relationships(database):
    """
    Creates a relationship mapping of tables to related tables (without keys).
    :param database: The database to create the mapping for.
    :type database: Database
    :return: A dictionary that has a table to related tables list.
    :rtype: dict of list of str
    """
    table_relationship_map = {}
    for table in database.tables.values():
        related_tables = set()
        for foreign_key in table.foreign_keys.values():
            related_tables.add(foreign_key.to_table)
        table_relationship_map[table.table_name] = list(related_tables)

        for relationship in table.relationships.values():
            related_tables.add(relationship.to_table)
        table_relationship_map[table.table_name] = list(related_tables)

    return table_relationship_map