Is it possible for a primary key to consist of multiple fields in a database table?

Yes, a primary key in a database table can consist of multiple fields. Such a key is called a composite (or concatenated) primary key. It is used when the uniqueness of a record is determined by a combination of values from several columns, rather than just one. For example, in an orders table, where the uniqueness is determined by the pair (order_id, product_id).