ISO 10303-22:1998 pdf download – lndustrial automation systems and integration – Product data representationand exchange – Part 22: lmplementation methods: Standard data access interface.
10.2 Fundamental concepts and assumptions
The following conipts and assumptions ;ipply
— the characierisucs o(thc parameters of the SDAI operations are described in the SDAI dictionary schema, the S1)Al session schema and the Sl)AI population schema The subypc relationships hetween types of entity instances is described in the SI)AI paranwtcr data schema.
— entity instance operations are applicable to all instances of any entity data type defined in any SDAI or application schema available to the application;
— application instance operations are applicable only to instances of entity data types defined in application schemas available to the application;
— when an operation needs to access an entity instance in an SDAI-model that is not active in the current session and the repository containing that SI)Al-rnodel is open. function equivalent to the Start read-only access operation shall be automatically applied to that SDAI-modcl. When the repository containing the SDAI-niodcl is not open, the repository shall not be opened automatically. the SDAI-model shall not he opened automatically and an error shall result,
— when an operation terminates unsuccessfully, the values at the Input parameters will be unchanged. The effect on the Output parameters is not specified in this part at ISO 10303;
— for implementations not supporting access to the Sl)AI data dictionary. support for the SDAI operations th.a specif an inaancc from the SPAI diciionai schema is pros iskd by supporting SDAI language binding operations where these paranwtcrs are specified by name;
— thr operations where an entriy instance attribute is an input parameter. the atinbute may have been declared directly in the entity_definition upon which the entity_instance is based or it may have been inherited from a supertype of that entity definition For SPA! language bindings adding support for specifying parameters by manic, the case where attnhutcs of the same name arc inherited from different supertvpes shall he handled by prefising the attribute name with the name of the supcrtvpc cntity type from which the attribute is inherited (see ISO 10303-Il:;
— th behaviour of operations accessing an aggregate Instance through its identifier or through an Iterator shen other operations are used to add. modify, remove or delete members of the aggregate instance is not specified in this pan of ISO 14)303;
— all iterators whose subject aggregate has been deleted shall be deleted at the end of an SDAI session and may be deleted earlier depending on the implementation or the dictates of the programming language of the particular binding such that the AI_NFXS or 1k .NhXS error shall result when the iteralor is used as a parameter to an SDAI operation;
— set, bag and list instances are managed differently from array Instances by SDAI operations with respect to their hounds The lower bound and upper bound for set. bag and list instances are considered Constraints on the number of elements that a valid instance of the set. bag or list may contain. These hounds have no effect on the operations that create, add elements to or remove elements from sets, bags and lists;
schema instance.change date for any modified or created schema_instance shall be set to the current date.
sdai_model.change_date for any modified or created sdai_niodel skill be set to the current date.
10.4.9 Abort
•This operation restores the condition of the contents SOAI models and schema instances. of all open repositories to that which esisted at the lime of the last Stan transaction read-write or Commit operation whichever operauon occurred most recently All deleted instances are restored, all created instances no longer exist and all modifications to instances are lost- The existing read-write transaction continues to he active. This operation performs no function in the case where the current transaction is read-only.