SQLite Forum

How is a table with only primary key stored on disk?
> Are the "keys" mentioned in the manual the same as the "keys" in SQL code? The word "keys" mean differently in different context.

One would expect so, yes.  A "key" is a concatenation of the fields comprising the key (as in the key_column_list) followed by the components of the primary key of the underlying record that are not already included in the key_column_list.  This ensures that every "key" is unique.

In the case of a ROWID table, the primary key is always the ROWID, although there is "syntactic sugar" that permits the use of the term "PRIMARY KEY" as use-one-time-per-declaration alternate spelling for UNIQUE.