ISO 10303-22:1998

Overview

ISO 10303-22:1998 is Part 22 of the ISO 10303 family (STEP) and specifies the Standard Data Access Interface (SDAI) - an implementation-level interface for accessing and manipulating product data represented using the EXPRESS schema language. This part of ISO 10303 provides the framework and methods implementers use to map product data models into programming interfaces and run-time services so that applications can create, read, validate and exchange STEP-conformant product data.

Key topics

• Standard Data Access Interface (SDAI): definition of an access interface that decouples application logic from underlying product-data representations.
• Implementation methods: guidance for implementing SDAI in software, including schema bindings and run-time behaviour.
• EXPRESS schema listings: machine-readable EXPRESS descriptions related to the SDAI are provided; Annex E lists these EXPRESS schemas (available in computer-interpretable form at the NIST URL below).
• Data model conformance and validation: requirements to ensure instances conform to EXPRESS-defined constraints (described at an implementation level).
• Repository and instance management (implementation scope): mechanisms for creating, storing, and managing instances of EXPRESS entities as exposed by SDAI implementations.

(Note: this summary highlights the technical scope implied by the Part 22 title and the document structure; Annex E EXPRESS listings are published electronically.)

Relevant resource: http://www.nist.gov/sc4/step/parts/part022/current/part22.exp

Applications

ISO 10303-22 (SDAI) is used where reliable, standardized programmatic access to STEP product data is required:

• CAD/CAM/CAE integrations - enabling tools to read/write STEP data through a common API.
• PDM / PLM systems - implementing persistent storage and interchange of product structures and metadata.
• Manufacturing automation & systems integration - allowing process systems to exchange product definitions in a consistent way.
• Custom software and middleware - developing language bindings or services that expose EXPRESS-based models to applications.

Who uses this standard

• Software developers and architects implementing STEP-enabled applications or middleware.
• PLM/PDM and CAD software vendors integrating STEP import/export and persistent repositories.
• Systems integrators and implementers mapping EXPRESS schemas to programming languages.
• Test labs and standards bodies verifying conformance of SDAI implementations.

Related standards

• Other parts of ISO 10303 (STEP) that define EXPRESS schemas, file exchange protocols and application protocols.
• Implementation guides and language-binding documents that complement SDAI for specific programming environments.

ISO 10303-22 remains a core reference for organizations building interoperable product-data access solutions based on STEP and EXPRESS.