cleanup of 2.2
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@ -269,23 +269,24 @@ software we are interested in.
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\subsection{The database abstraction}
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Database systems are often thought of in terms of the high-level
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abstractions they present. For instance, Relational database systems
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implement the relation model~\cite{cobb}, while object oriented
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abstractions they present. For instance, relational database systems
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implement the relational model~\cite{cobb}, object oriented
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databases implement object abstractions, XML databases implement
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hierarchical datasets, and so on. Before the relational model,
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navigational databases implemented a navigational, pointer and record
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based data model.
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navigational databases implemented pointer and record
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based data models.
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An early survey of database implementations sought to enumerate the
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fundamental components used by database system implementors. This
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survey was performed due to difficulties in extending database systems
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into new application domains. The survey divided databases into two
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broad modules: conceptual mappings~\cite{batoryConceptual} and the
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physical database~\cite{batoryPhysical} model.
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into new application domains. The survey divided internal database
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routines into two broad modules: conceptual
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mappings~\cite{batoryConceptual} and the physical
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database~\cite{batoryPhysical} model.
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A conceptual mapping may translate a relation into a set of keyed
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tuples. A physical model may translate a set of tuples into an
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on-disk B-Tree with support for iterators and range-based query
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A conceptual mapping might translate a relation into a set of keyed
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tuples. A physical model could then translate a set of tuples into an
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on-disk B-Tree, and provide support for iterators and range-based query
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operations.
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It is the responsibility of a database implementor to choose a set of
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@ -298,10 +299,10 @@ top of it.
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can support more than a small percentage of today's applications.}
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Instead of attempting to create such a model after decades of database
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research has failed to produce one, we opt to provide a storage model
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that mimics the primitives provided by modern hardware as closely as
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possible. This makes it easy for system designers to implement most
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of the data models that the underlying hardware can support.
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research has failed to produce one, we opt to provide a transactional
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storage model that mimics the primitives provided by modern hardware.
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This makes it easy for system designers to implement most of the data
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models that the underlying hardware is capable of supporting.
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\subsection{\yad and ``traditional'' database workloads}
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