The following diagram shows the high-level overview
architecture of the FDO API and included FDO providers. For clarity,
only the underlying data source details for the OSGeo FDO Provider
for MySQL, OSGeo FDO Provider for ArcSDE, and OSGeo FDO Provider
for SDF are shown as examples. Similar data store, schema, and data
connection information is available for the other providers.
FDO Packages
FDO
is assembled in conceptual packages of similar functionality. This
conceptual packaging is reflected in the substructure of the FDO
SDK “includes” folder. For more information about the structure,
see The Essential FDO.
FDO commands, provider-specific commands, and
connections and capabilities provide access to native data stores
through each different FDO provider. Schema management (through
XML), client services, and filters and expressions are provider-independent
packages that tie into the FDO API. Each of these are explained
in more detail in subsequent sections.
The FDO API consists of classes grouped within
the following packages:
-
Commands
package. Contains a collection of classes that provide
the commands allowing the application to select and update features,
define new types of feature classes, lock features, and perform
analysis on features. Each Command object executes a specific type
of command against the underlying data store. In addition, FDO providers
expose one or more Command objects.
-
Connections/Capabilities. Contains
a collection of classes that establish and manage the connection
to the underlying data store. Connection objects implement the FdoIConnection
interface. Capabilities API provides the code for retrieving the
various FDO provider capability categories, such as connection or
schema capabilities. You can use this this API to determine the
capabilities of a particular provider.
-
Filters
and Expression package. Contains a collection of classes
that define filters and expression in FDO, which are used to identify
a subset of objects of an FDO data store.
-
Client
Services package. Contains a collection of classes that
define the client services in FDO that, for example, enable support
for dynamic creation of connection objects given a provider name.
-
Schema
package and FDO XML. Contains a collection of classes
that provides a logical mechanism for specifying how to represent
geospatial features. The FDO feature schema is based somewhat on
a subset of the OpenGIS and ISO feature models. FDO feature schemas
can be written to an XML file. The FdoFeatureSchema and FdoFeatureSchemaCollection classes
support the FdoXmlSerializable interface.
In addition, FDO is integrated with the Geometry
API, which includes the classes that support specific Autodesk applications
and APIs, including FDO.
For more information about each of the FDO packages,
see FDO
API Reference Help and subsequent chapters in this guide.
Provider API(s) complete the FDO API configuration.
Each provider has a separate API reference Help.