Oracle Objects for OLE in Oracle Database 10g

Features Overview

March 2004

 

 

Product Summary

Oracle Objects for OLE (OO4O) is a COM-based database connectivity tool that combines seamless and optimized access to Oracle databases with easy to use interfaces. OO4O can be used in a variety of environments ranging from web applications to n-tier client/server applications. It can be used from virtually any programming or scripting language that supports the Microsoft COM Automation technology, such as Visual Basic, Active Server Pages, Visual C++, VBA in Excel, PowerBuilder, Delphi, Microsoft Internet Information Server, and COM+/Microsoft Transaction Server.

Because it is an Oracle native driver, OO4O provides fast performance on Windows clients to Oracle databases. It does not incur the overhead of ODBC and OLE DB drivers. OO4O has been developed and has evolved specifically for use with Oracle database servers. It provides easy access to features that are unique to Oracle, but are otherwise cumbersome or inaccessible to use from ODBC and OLE DB-based components, such as ADO.

Components

OO4O consists of an in-process COM Automation Server, a C++ class library, and the Oracle Data Control.

  • In-Process COM Automation Server: a set of COM Automation interfaces/objects for connecting to Oracle database servers, executing queries and managing the results.
  • C++ Class Library: a set of COM Automation interfaces/objects for connecting to Oracle database servers, executing queries and managing the results.
  • Oracle Data Control: an ActiveX Control that greatly simplifies the exchange of data between query results and popular data-aware visual controls, such as edit, list and grid controls. The Oracle Data Control supports virtually data-aware controls that can be bound to the Microsoft Data Control in Visual Basic.

Features

OO4O includes the following major features:

  • Oracle 10g Grid enabled, allowing developers to take full advantage of grid support without changes being required to existing code
  • Full support for PL/SQL, including seamless access to PL/SQL Cursors
  • Tunable client-side, scrollable and updateable cursors for easy and efficient access to result sets of any size
  • Support for array fetches, updates, and inserts resulting in reduced network roundtrips
  • Connection pooling to allow development of scalable mid-tier application components, such as IIS Active Server Pages that heavily use and serve dynamic content stored in Oracle database servers
  • Thread safety allowing safe access to automation objects in multithreaded environments
  • Small disk and memory footprint
  • Efficient management of database connections and user sessions (connection pooling and multiplexing)
  • Full support for COM+/Microsoft Transaction Server (MTS) coordinated transactions
  • Seamless access to instances of advanced Oracle data types:
    • Object References (REFs)
    • Object Instances (Objects)
    • Nested Tables
    • VARRAYs
    • BLOBs, CLOBs, NCLOBs and BFILEs
  • Support for new BINARY_FLOAT, BINARY_DOUBLE, TIMESTAMP and INTERVAL datatypes
  • Easy to use interface for describing schema objects
  • Full support for accessing Advanced Queuing capabilities
  • Support for publishing, detecting, and subscribing to database events
  • Temporary LOB support for calling stored procedures or functions that have LOB arguments
  • XML generation
  • Full UCS2 Unicode Support
  • Asynchronous processing of PL/SQL and SQL
  • Application failover notification
  • Detection of Lost Connections
  • The Oracle Code Wizard for Stored Procedures, which automatically generates OO4O code that executes PL/SQL or Java stored procedures

Below are descriptions of some of the major features:

Transparent Oracle 10g Grid Support

OO4O is grid enabled. To take full advantage of the power of Oracle 10g grid technology, no OO4O code changes are required! OO4O automatically recognizes when it is connected to a database grid and provides full support for Oracle grid features.

Support for Advanced Oracle Data Types

OO4O provides full support for accessing and manipulating instances of REFs, value instance, Variable-length arrays (VARRAYs), Nested tables, and LOBs.

Instances of these types can be fetched from the database or passed as input or output variables to SQL statements and PL/SQL blocks, including stored procedures and functions. All instances are mapped to COM Automation Interfaces that provide methods for dynamic attribute access and manipulation.

Support for COM+/Microsoft Transaction Server

COM+/MTS is essentially a COM-based TP-Monitor and relies on the Microsoft Distributed Transaction Coordinator (DTC) for distributed transaction support. Oracle database transactions initiated in OO4O automatically participate in global transactions coordinated by the MS DTC in MTS, provided that Oracle Services for MTS is installed and running. Database connections established in components deployed in MTS can also be pooled via the Oracle Services for MTS.

The Oracle Services for MTS has been architected to improve the availability and scalability of OO4O applications using this application stack. The new architecture removes the single point of failure and bottlenecks that were present in previous versions. This redesign is transparent without any application code changes being required.

Advanced Queuing Interface

OO4O provides interfaces for accessing the Advanced Queuing (AQ) feature in the Oracle database. It makes AQ accessible from popular COM-based development environments, such as Visual Basic.

The OraAQ Automation interface provides methods for enqueuing and dequeuing messages (OraAQMsg). It also provides a method for monitoring queues for message arrivals. Client applications are notified when messages of interest are dequeued via a callback object.

Database Events

OO4O includes support for publishing, detecting, and subscribing to database events. By allowing OO4O to publish and subscribe to events, Windows clients can interact closely with the Oracle database. This functionality allows server-side events to initiate client and middle-tier actions, and vice-versa.

Application Failover Notification

OO4O supports Application Failover Notifications. Application Failover Notifications can be used in the event of the failure of one database instance and failover to another instance. Because of the delay which can occur during failover, the application developer may want to inform the user that failover is in progress, and request that the user stand by. To receive Failover notifications, a notification handler must be registered with the MonitorForFailover method of the OraDatabase object.

Connection Multiplexing

OO4O allows multiple user sessions to share a network connection to an Oracle Server. This capability is particularly useful for application components that use OO4O in n-tier distributed environments, such as a web environment.

Describing Schema Objects

OO4O includes interfaces for retrieving attributes of schema objects. Using the Describe method of the OraDatabase interface retrieves attributes. This method takes the name of a schema object (e.g. emp) and returns a COM Automation object (OraMetaData). OraMetaData provides methods for dynamically navigating and accessing all the attributes (OraMDAttribute collection) of a schema object described.

XML Support

XML is the most commonly used markup language for data used by Internet applications. OO4O allows users to easily extract data from the Oracle database in XML. The XML support also includes the ability to render XML for Oracle advanced data types and to control the XML output format.

Asynchronous Processing of SQL and PL/SQL

OO4O enables the developer to execute SQL or PL/SQL commands using asynchronous processing. This means that control is returned to the application immediately even if the execution is not complete. This enables additional work to performed while waiting for the results of a query or stored procedure call to return.

Full Unicode Support

As more business applications become Internet-centric and globally accessible, the need to simplify application development in multiple written languages arises. Unicode is the universal character set standard that encodes all characters from languages worldwide. It provides the basis for global computing by allowing applications to be written once, then deployed in any and all languages.

OO4O offers full UCS2 Unicode support. Using Unicode in OO4O is transparent, requiring no application code changes. This makes developing global applications with OO4O easy and fast.

Support for New Oracle 10g Datatypes

OO4O includes significant new support for Oracle's newest data types. BINARY_DOUBLE and BINARY_FLOAT data types represent single-precision and double-precision floating-point values that mostly conform to the IEEE754 standard for Floating Point Arithmetic. These new types enable faster arithmetic calculations and reduce storage requirements. They also enable you to implement published algorithms that specify IEEE behavior for arithmetic operations. Intense number crunching computations (whose scale and precision requests can be accommodated by the IEEE types) will run very substantially faster using these types than using NUMBER. Additionally, this feature enables cleaner integration with XML and Java environments because it provides similar numeric datatypes for those environments.

OO4O now provides support for the TIMESTAMP and INTERVAL datatypes. These are available through the new OraIntervalDS, OraIntervalYM, OraTimeStamp, and OraTimeStampTZ OO4O objects. These represent improvements over the DATE data type with greater information included and a higher precision. The TIMESTAMP data types can provide time zone information and have precision up to the nanosecond. The two Oracle INTERVAL types provide year to month and day to nanosecond information when comparing timestamps.

Support for Multiple Oracle Homes

OO4O can be installed in a Multiple Oracle Home environment beginning with Oracle Database 10g. However, because OO4O is a COM component, only one instance can be active at a time. This means that a later OO4O installation will render the previous one inactive. A client can toggle between installed OO4O client releases by using the Oracle Installer.

 

 

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