15.2. Object-Oriented Data Model (OODM)
As we discussed in the earlier chapters, the relational data model was first produced by Dr. E.F. Codd in his seminal paper, which addressed the disadvantages of legacy database approaches such as hierarchical and network (CODASYL) databases. Since then, more than hundred commercial relational DBMSs have been developed and put in use both for mainframe and PC environments. However, RDBMSs have their own disadvantages, particularly, limited modelling capabilities. Various data models were developed and implemented for database design that represents the ‘real-world’ more closely. Fig. 15.1 shows the history of data models.
Fig. 15.1. History of evolution of data model
Each data ...