When starting with databases, one of the first things people learn is data normalization. Normalization makes a lot of sense because it helps to reduce redundancy and it ensures that data is structured in a professional and nice way.
However, in some cases, normalization is taken way too far.
As mentioned in many cases, normalization can be easily exaggerated. In such a case, performance will suffer and things will be really complex. Here is an example of normalization taken too far: a few years ago, a professor at a local university confronted me with an interesting example when I was talking to students. He told me that he uses the following example to explain to students that normalization can easily be taken too far. He invented the 7th normal form (which, of course, does not exist in professional database literature).
Here is an example:
test=# CREATE TABLE t_test (name text);
CREATE TABLE
test=# INSERT INTO t_test VALUES ('sealevel');
INSERT...