71.   This model is, however, unrealistic.

72.   The entity model is an abstract representation of the data within the organisation.

73.   The model should be a global view.

74.   The entity-relationship model is a data model, referred to in this book as the conceptual schema or conceptual model.

75.   Otherwise the data model will not be as useful as possible.

76.   If the entity model is inaccurate so will be the database and the applications that use it.

77.   The relational model is not computer-oriented.

78.   Although the network model is more flexible than the hierarchy, the overall structure is fairly complex to implement and requires extra storage space to handle the pointers.

79.   Research has however shown that in terms of the arrangement of the protein molecules this model is no longer accurate.

80.   The obvious model is Austria, though getting there may yet take time.