In a lecture, my lecturer showed us a table without a primary key. Upon questioning, he said that in 3NF when you remove transitive dependencies it's ok to then have a table without a primary key.
However, no primary key implies there's no functional dependencies - but 3NF is the removal of transitive dependencies, and I was taught that each table needs to have a primary key for normalization as it's all about functional dependencies.
I know it's fully possible to create a table without a primary key, but is that database considered normalized if that table exists?
I should add, the table doesn't have any “unique key”, no primary, no composite, no foreign.
The table shown has three attributes with none of them labeled as primary or unique. I asked if it was a mistake and he said it's fine to not have one. I questioned the remark as none of the information in the table can be uniquely identified and he claimed it's ok to be like this. This goes against what I was taught about normalisation.