@article{DBLP:persons/Codd69,
  author    = {E. F. Codd},
  title     = {Derivability, Redundancy and Consistency of Relations Stored
               in Large Data Banks},
  journal   = {IBM Research Report, San Jose, California},
  volume    = {RJ599},
  year      = {1969},
  ee        = {db/labs/ibm/RJ599.html},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}

and 

@article{DBLP:persons/Codd71a,
  author    = {E. F. Codd},
  title     = {Further Normalization of the Data Base Relational Model},
  journal   = {IBM Research Report, San Jose, California},
  volume    = {RJ909},
  year      = {1971},
  ee        = {db/labs/ibm/RJ909.html},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}
In Peter Chen's 1976 paper he specifically mentions the relational model in the abstract
"A data model, called the entity-relationship model, is proposed. This model incorporates some of the important semantic information about the real world. A special diagrammatic technique is introduced as a tool for database design. An example of database design and description using the model and the diagrammatic technique is given. Some implications for data integrity, infor-mation retrieval, and data manipulation are discussed. The entity-relationship model can be used as a basis for unification of different views of data: t,he network model, the relational model, and the entity set model. Semantic ambiguities in these models are analyzed. Possible ways to derive their views of data from the entity-relationship model are presented. Key Words and Phrases: database design, logical view of data, semantics of data, data models, entity-relationship model, relational model, Data Base Task Group, network model, entity set"

So, I am not sure why you (Michael) think they got their history wrong?


--Tim