- Table has a name that is distinct from all other tables in the database.
- There are no duplicate rows, each row is distinct.
- Entries in columns are atomic (no repeating groups or multivalued attributes)
- Entries from columns are from the same domain based on their data type:
number (numeric, integer, float, smallint,…)
logical (true or false)
- Operations combining different data types are disallowed
- Each attribute has a distinct name
- sequence of columns is insignificant
- sequence of rows is insignificant