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 server.
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)
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.
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.
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.