Most relational database management systems do not support nested records, so tables are in first normal form by default.
[3] The following scenarios first illustrate how a database design might violate first normal form, followed by examples that comply.
Reduced structural complexity gives users, applications, and DBMSs more power and flexibility to formulate and evaluate the queries.
The process can be applied recursively to non-simple domains nested in multiple levels.
The data structure places all of the values on an equal footing, exposing each to the DBMS directly, so each can potentially participate directly in queries; whereas in the previous situation some values were embedded in lower-level structures that had to be handled specially.
It is worth noting that this design meets the additional requirements for second and third normal form.
Codd states that the "values in the domains on which each relation is defined are required to be atomic with respect to the DBMS.
According to Date's definition, a table is in first normal form if and only if it is "isomorphic to some relation", which means, specifically, that it satisfies the following five conditions:[11] Violation of any of these conditions would mean that the table is not strictly relational, and therefore that it is not in first normal form.