These were two technology authors who were quoted on the subject of Relational Integrity and a Normalized Data Model. Their ideas of reducing redundancy in the physical data schema and protecting the mandatory relationships between entities took a whole lot of attention about how to create, define, and manage data so that it was safe and intact for application usage.
They had rules and a syntax for defining data and a normalization process for creating a Data Definition Language (DDL) and Data Manipulation Language (DML) for all data necessary to support the functions of applications.
Use this link for a more detailed discussion on Normalization: http://en.wikipedia.org/wiki/Database_normalization#Free_the_database_of_modification_anomalies
Then, Object Orientation came along and added Methods, Self Contained Data, Anthropomorphism and some other terminology that, although valuable and additive to the definition of solutions, took our eyes off the ball of data modeling principles that are STILL fundamental to a reliable and cohesive solution to business and organizational needs.
Why have we let this happen?