INTRODUCTION
The introduction of the Microsoft .NET Framework has produced a new Windows application server environment different from COM. With COM, data can be accessed from an Oracle database through either Oracle Objects for OLE (OO4O), ADO/OLE DB, or ODBC. In a .NET environment, users still can access the Oracle database via OLE DB and ODBC using a data access bridge provided by Microsoft. For OLE DB, this bridge is OLE DB .NET; For ODBC, the bridge is ODBC .NET. These bridges provide interoperability between the managed .NET layer and unmanaged COM or Win32 layer. The Oracle Data Provider for .NET (ODP.NET) represents the third method for accessing the Oracle database.
DIFFERENCES WITH OTHER .NET DATA PROVIDERS
Among the three data access methods, ODP.NET is the most
native to the .NET environment, bypassing the need for OLE DB or ODBC. It features high performance access to the
Oracle database, while providing access to advanced Oracle functionality not
available through OLE DB .NET and ODBC .NET. Similar to OLE DB .NET and ODBC .NET, ODP.NET can be used from any .NET
language, such as C# and Visual Basic .NET. An important distinction is that ODP.NET does not use an extra data
access bridge; thus, it will have better performance than OLE DB .NET and ODBC
.NET. Additionally, because these .NET bridges are built for generic data sources, they do not provide full access to
advanced database functionality. These three .NET data providers are shown in Figure 1.
Figure 1: Oracle .NET Data Access
Major Features
ODP.NET makes using
the Oracle database from .NET more flexible, fast, and stable than other .NET
providers. It is part of the Oracle9i Release 2 Client, but can be used with
any Oracle8, Oracle8i, or Oracle9i database server. Highlighted here are some
of ODP.NET's key features.
XML Features
With XML becoming a
popular language for data integration and web services, many .NET programmers
are using it in their applications. ODP.NET provides two ways for programmers
to exploit XML: XML DB and System.XML services.
XML DB is Oracle's high-performance, native XML storage and retrieval technology
available with Oracle9i Release 2 database server. It provides a unique ability
to store and manage both structured and unstructured data under a standard W3C
XML data model. XML DB provides complete transparency and interchangeability
between the XML and SQL metaphors. ODP.NET fully exposes all of XML DB's
functionality to .NET clients. .NET clients make PL/SQL calls from ODP.NET to
invoke XML DB's functionality. Click here for more information on
XML DB.
Microsoft System.XML services are a set of interfaces for manipulating XML data
sets from .NET data providers. ODP.NET interoperates with the System.XML APIs,
feeding it data via the ODP.NET DataAdapter interfaces. One of the main
differences between using XML DB and System.XML is that the former provides
XML services where the data resides, on the database server. The latter
manipulates XML on the client side. As such, ODP.NET provides great flexibility
for programmers to choose the XML technology that best fits their project
requirements.
Performance
One of ODP.NET's
key differentiators over OLE DB .NET and ODBC .NET is better performance. As
explained before, ODP.NET is native to the .NET environment, so it does not
use a data access bridge, as is the case with the other two data access methods.
A data access bridge is an additional layer of indirection for data to travel
through. This not only means degraded performance, but also can introduce
instability into the data access layer. An extra layer creates more potential
for instability as it is another layer where bugs may appear. Furthermore,
ODP.NET has many optimizations for retrieving and manipulating Oracle native
types, such as LOBs and REF Cursors, whereas OLE DB .NET and ODBC .NET have very
few.
.NET data access
performance can be additionally improved by using the many tuning features
available with ODP.NET. The settings of these tuning features will be
determined by what fits your application usage profile best. Tuning features
include:
- Connection pooling - sets up a pool of
connections for an application, allowing connection lifetime, minimum
and maximum pool size to be set
- Prefetching rows - specifies the number of rows
that are to be fetched per server round trip
- Data chunk size (LONGs, LONG RAWs) - specifies the size of
non-scalar data to be fetched
Native Oracle Types
In .NET, Microsoft
has introduced a set of unified data types among the different .NET programming
languages. With ODP.NET, Oracle users have access to .NET data types as well
as Oracle native types. Oracle types can be fully manipulated within a .NET
application and interoperate with .NET data types. Oracle native types provide
advanced functionality to store and retrieve specialized data structures from
the database, such as XML or Microsoft Word documents. Even with common types
such as OraDecimal, the equivalent to the .NET decimal type, Oracle types
provide better functionality. In the case of OraDecimal, it provides a higher
level of precision at 38 than .NET decimal with a 28 precision.
ODP.NET supports
the gamut of advanced Oracle types, including REF Cursors, LOBs (CLOBs, BLOBs,
NCLOBs), BFILEs, Longs, RAWs, LONG RAWs, and N-data types. One of the
limitations of using OLE DB .NET or ODBC .NET is that users cannot fully
manipulate Oracle types. For example, in ODP.NET, multiple REF Cursor objects
obtained as PL/SQL output parameters can be accessed in an arbitrary way.
With the other two data access methods, REF Cursors must be accessed in a
linear method.
Other Major
Features
ODP.NET exposes
many other Oracle database features, including PL/SQL, transactional, and
Unicode support. ODP.NET users can fully execute PL/SQL stored procedures and
functions in the database. PL/SQL can be packaged or non-packaged. Programmers
are provided significant flexibility in using PL/SQL, including the ability
to return multiple result sets from a stored procedure.
ODP.NET can
participate in transactional applications with the Oracle database as the
resource manager. ODP.NET employs Microsoft Enterprise Services as the
transaction coordinator in a .NET environment. The Oracle Services for
Microsoft Transaction Server (OraMTS) acts as a proxy among ODP.NET,
Enterprise Services, and the Oracle database in order to coordinate these
transactions. OraMTS provides a robust architecture for ODP.NET programmers
to have their transactional applications maintain high availability and
perform in a scalable manner.
ODP.NET has full
Unicode support so that .NET users can globalize their applications easily
in multiple written languages. This makes deploying applications in a
multilingual environment easier and faster.
CONCLUSION
ODP.NET gives
programmers better performance, flexibility, and feature selection for their
.NET applications. With it, developers can use .NET, but not have to sacrifice
the powerful data management capabilities that Oracle provides. For more
information, visit the
ODP.NET web page.
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