Is it possible for a database table to not contain a unique identifier or primary key?

It is technically possible for a database table not to contain a unique identifier or primary key, but this is considered bad practice.

Without a primary key:

• It is difficult to uniquely identify records.
• It is challenging to update or delete specific rows.
• Data normalization and integrity are compromised.

Sometimes, such tables are found in legacy systems or during data import, but it is generally recommended to add a unique identifier (such as an auto-incrementing field) or a composite key.

If there is no unique identifier, a combination of several fields can be used as a composite key to ensure uniqueness.