Support for Oracle Object-Relational and LOB Datatypes

Oracle Objects for OLE C++ Class Library provides full support for accessing and manipulating instances of REFs, value instances, variable-length arrays (VARRAYs), nested tables, and LOBs in an Oracle database.

The Oracle Object-Relational and LOB Datatypes diagram illustrates the containment hierarchy for instances of all types in Oracle Objects for OLE.

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. These interfaces may be obtained from:

· The value property of an OField object in a Dynaset

· The value property of an OParameter object used as an input or an output parameter in SQL Statements or PL/SQL blocks

· An attribute of another object/REF instance

· An element in a collection (VARRAY or a Nested Table)

OObject

The OObject interface is a representation of an Oracle embedded object or a value instance. It contains a collection interface for accessing and manipulating (updating and inserting) individual attributes of a value instance. Individual attributes of an OAttributes collection interface can be accessed by using a subscript or the name of the attribute.

ORef

The ORef interface represents an instance of a referenceable object (REF) in client applications. The object attributes are accessed in the same manner as attributes of an object represented by the OObject interface. ORef is derived from an OObject interface through the containment mechanism in COM. REF objects are updated and deleted independent of the context they originated from, such as Dynasets. The ORef interface also encapsulates the functionality for navigating through graphs of objects utilizing the Complex Object Retrieval Capability (COR) in OCI.

OCollection

The OCollection interface provides methods for accessing and manipulating Oracle collection types, namely variable-length array (VARRAYs) and Nested Tables in OO4O. Elements contained in a collection are accessed by subscripts.

OBlob and OClob

OBlob and OClob interfaces provide methods for performing operations on large objects in the database including Blob, Clob and Nclob, and Bfile data types. For information on Bfiles, see OBfile.