Unrelated tables and time intervals
Thank you for your response on my queries.

My thoughts on this:


Periods are only to label your data
It is not labeling every data of your database
Since as per your clarifications "When inserted, it is not checked if there is a period to insert the information", periods may overlapped each other
Query is not essentially labeling every data with a periods
Database is very small in size,


Linking a table to others needs some sort of consistency which is not available in this case.  Seeing these inputs, IMHO, we can safely keep this table as separate entity.

From Performance aspects, we can make better indexes based on our application's need on period table to avoid any bottleneck.

Thank you,

Sanjeeva