 There are also object databases that can be used to replace RDBMSs, but these have not been as technically and commercially successful as RDBMSs.OOP can be used to associate real-world objects and processes with digital counterparts.However, not everyone agrees that OOP facilitates direct real-world mapping (see Criticism section) or that real-world mapping is even a worthy goal; Bertrand Meyer argues in "Object-Oriented Software Construction" that a program is not a model of the world but a model of some part of the world; "Reality is a cousin twice removed".