Are there any good reasons to have a database table without an integer primary key?

Question

Although I\'m guilty of this crime, it seems to me there can\'t be any good reason for a table to not have an identity field primary key.

Pros: - whether you want to o

Answer 1

I know for sure that some very smart people working for web giants do this. While I don't know why their own reasons, I know 2 cases where PK-less tables make sense:

• Importing data. The table is temporary. Insertions and whole table scans need to be as fast as possible. Also, we need to accept duplicate records. Later we will clean the data, but the import process needs to work.
• Analytics in a DBMS. Identifying a row is not useful - if we need to do it, it is not analytics. We just need a non-relational, redundant, horrible blob that looks like a table. We will build summary tables or materialized views by writing proper SQL queries.

Note that these cases have good reasons to be non-relational. But normally your tables should be relational, so... yes, they need a primary key.