Sure, in the 1970 paper "A Relational Model of Data for Large Shared Data Banks" where E.F.Codd introduced the relational model, he specifically mention how it is superior to hierarchical and graph databases, which were the dominant models at the time.
The hierarchical database evolved from the flat file database by allowing nested records (i.e a record could have sets of child records, arbitrary deep). The graph model further added support for navigation links or pointers between records across the structure, hence supporting a graph model (also commonly called network model at the time).
The hierarchical database evolved from the flat file database by allowing nested records (i.e a record could have sets of child records, arbitrary deep). The graph model further added support for navigation links or pointers between records across the structure, hence supporting a graph model (also commonly called network model at the time).