The FDO API provides a common, general purpose abstraction layer for accessing geospatial data from a variety of data sources. The API is, in part, an interface specification of the abstraction layer. A provider, such as Autodesk FDO Provider for Oracle, is an implementation of the interface for a specific type of data source (for example, for an Oracle relational database). The API supports the standard data store manipulation operations, such as querying, updating, versioning, locking, and others. It also supports analysis.
The API includes an extensive set of methods that return information about the capabilities of the underlying data source. For example, one method indicates whether the data source supports the creation of multiple schemas, and another indicates whether the data source supports schema modification.
A core set of services for providers is also available in the API, such as provider registration, schema management, filter and expression construction, and XML serialization and deserialization.
The API uses an object-oriented model for the construction of feature schema. A feature is a class, and its attributes, including its geometry, are a property of the class. The instantiation of a feature class, a Feature Data Object (FDO), can contain other FDOs.