THE that current database research can deal with advanced data applications trend is toward systems that go
beyond the standard “office” database application. This trend is reflected in the research on object-oriented databases .
Along with this trend, the need for better database end-user interfaces has been stressed [30],[36]. To this end, the 2-D
nature of a computer screen should be fully exploited. It seems natural that in order to achieve these goals, graphs are used as the basic data type. Graphs have indeed been an integral part of the database
design process ever since the introduction of semantic and, more recently, object-oriented data models [191, [20], [ 2 S ] .
Their usage in data manipulation languages, however, is far
less common. To deal with the language component, schemes
in semantic and object-oriented data models are typically
transformed into a conceptual data model such as the relational
model. The required database language features then become
those of the conceptual model.
Some semantic and object-oriented data models are
equipped with their own data language. DAPLEX [29], for
example, is a data language for the Functional Data Model.
Even though databases in DAPLEX can be conveniently
THE that current database research can deal with advanced data applications trend is toward systems that gobeyond the standard “office” database application. This trend is reflected in the research on object-oriented databases .Along with this trend, the need for better database end-user interfaces has been stressed [30],[36]. To this end, the 2-Dnature of a computer screen should be fully exploited. It seems natural that in order to achieve these goals, graphs are used as the basic data type. Graphs have indeed been an integral part of the databasedesign process ever since the introduction of semantic and, more recently, object-oriented data models [191, [20], [ 2 S ] .Their usage in data manipulation languages, however, is farless common. To deal with the language component, schemesin semantic and object-oriented data models are typicallytransformed into a conceptual data model such as the relationalmodel. The required database language features then becomethose of the conceptual model.Some semantic and object-oriented data models areequipped with their own data language. DAPLEX [29], forexample, is a data language for the Functional Data Model.Even though databases in DAPLEX can be conveniently
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