It was defined in 1971 by Edgar F. Codd, an English computer scientist who invented the relational model for database management.
[1] A hypothetical example of a failure to meet third normal form would be a hospital database having a table of patients which included a column for the telephone number of their doctor.
Codd later realized that 3NF did not eliminate all undesirable data anomalies and developed a stronger version to address this in 1974, known as Boyce–Codd normal form.
Zaniolo's definition gives a clear sense of the difference between 3NF and the more stringent Boyce–Codd normal form (BCNF).
While this phrase is a useful mnemonic, the fact that it only mentions a single key means it defines some necessary but not sufficient conditions to satisfy the 2nd and 3rd normal forms.
"[9] The 3NF version of the definition is weaker than Date's BCNF variation, as the former is concerned only with ensuring that non-key attributes are dependent on keys.
While 3NF was ideal for machine processing, the segmented nature of the data model can be difficult to intuitively consume by a human user.
Analytics via query, reporting, and dashboards were often facilitated by a different type of data model that provided pre-calculated analysis such as trend lines, period-to-date calculations (month-to-date, quarter-to-date, year-to-date), cumulative calculations, basic statistics (average, standard deviation, moving averages) and previous period comparisons (year ago, month ago, week ago) e.g. dimensional modeling and beyond dimensional modeling, flattening of stars via Hadoop and data science.