JSDAI Introduction 

ISO-10303-21 file versus SDAI

ISO 10303 standards such as EXPRESS (part11), it's implementations Clear Text Encoding (part21) and SDAI (part22) are closely related to EXPRESS, but they don't know each other. In other words, there is no standard way to get a part21 file into SDAI and out of it. Even the concepts of these two implementations are different. Nevertheless there are two common concepts: entity-instance and EXPRESS-schema.

Within the complete Java programming language binding to SDAI we try to harmonize two implementation methods. There is an import and export operations by which a part21-file can be read into SDAI and written out. In order to do this we have to map SDAI and p21 concepts against each other.

Please note that this mapping is controversially discussed. There are possible alternatives. However we think that this mapping is the best compromise. Concrete applications show that this mapping is very handy.

Another aspect is that this mapping allows to import any p21-file into Java-SDAI. In order have all information the SDAI-repository got additional attributes, representing the file-header of p21. But export SDAI-repository into the p21 file is only possible if the following conditions are met:

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