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<h1>Basic Terms</h1>
<p>While relational and object databases use different sets of
terms, it is possible to draw parallels between some of the terms:</p>
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<p>OODBMS</p>
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<p>RDBMS</p>
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<p>Similar</p>
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<p>Different</p>
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<p>Class</p>
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<p>Table</p>
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<p>Define an entity data structure.</p>
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<p>Class can define fields (static data) and methods, while
table can only define static data.</p>
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<p>Object instance</p>
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<p>Tuple</p>
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<p>Represent an instance of data defined in a class or a
table.</p>
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<p>Object can hold data of different visibility and
references to other objects. Tuple consists of system type data. </p>
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<p>Attribute</p>
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<p>Column</p>
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<p>Define one of the fields in the data definition.</p>
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<p>RDBMS has a preset collection of types, which can be used
to define the type of the data in the column. OODBMS can use user-defined
types.</p>
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<p>Method</p>
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<p>Stored Procedure</p>
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<p>Define a piece of functionality.</p>
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<p>Method is a characteristic of a class. Stored procedure is
a separate object in RDBMS.</p>
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<p>Identity</p>
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<p>Key</p>
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<p>Identify a single object or tuple.</p>
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<p>Object identity makes any object unique independently of
the object content. Key imposes a uniqueness of a database object based on
the uniqueness of the column values.</p>
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<p>Reference</p>
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<p>Relation</p>
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<p>Link different objects within a database.</p>
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<p>In OODBMS direct object links are used. In RDBMS objects
are linked through foreign keys, i.e. identical values in different rows.</p>
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<p>Note, that the above-mentioned terms are similar only to a
certain degree; there are some fundamental differences between them.</p>
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This revision (1) was last Modified 2007-06-02T20:16:26 by Tetyana.
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