UVA DEPARTMENT OF COMPUTER SCIENCEOO-1Object-Oriented Data ModelWhy introduced?- characteristics of traditional database applications1. large # of similarly structured data with same size2. consists of fixed-length records (usually short)3. atomic fields: 1NF4. short transactions: execution time in the range of sec5. static conceptual schemasNew applications1. complex objects and complex internal structures2. behavioral data: distinct objects respond differentlyto the same command3. meta knowledge: rules in addition to tuples4. long-lived transactions, human interaction possible5. CAD, CAE, CAM, multimedia DB, etcUVA DEPARTMENT OF COMPUTER SCIENCEOO-2Notions in Object-Oriented Data ModelAn adaptation of OO programming paradigms to databasesEncapsulating data and code in objects- interface between objects: message to invoke methodClass- a means of grouping all objects that share the sameset of attributes and methods- an object belongs to only one class as an instance- enhance the system integrity by type checkingClass hierarchy and inheritance- allow deriving a new class from existing classes- subclass inherits all attributes and methodsof the superclass- single inheritance: one superclass- multiple inheritance: more than one superclass- ambiguity: potential name conflicts among
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