Data Exchange schema

A data exchange schema is required for any type of data exchange in order to provide the mapping rules between internal and external data. The data exchange schema is an intentional schema, i.e. it refers to structure definitions, only. Thus, a data exchange schema can apply on any collection (database) or file (external data source), which fits into the rules defined in the data exchange schema.

Data exchange schemata can be provided in different formats. The format of the data exchange schema does not depend on the file format for the external data source. Thus, one may still use the same data exchange schema definition, even though you have changed the format of the external file. Data exchange schemata can be provided in one of the following formats:

• Dictionary - Structure definition in an ODABA dictionary
• CSV/ESDF - Headline definition format
• OSI ODL - Schema definition language
• OXML - extended XML schema definition

The data exchange schema is an extension of a file schema, which defines additional mapping rules for assigning external data fields to database properties. Database property correspondences are always defined in the source attribute for the file property.

ODL and XML schema definitions follow the common rules for structure definitions in an ODABA schema definition, i.e. the property correspondence will be defined in the source attribute for each property of the external file. ESDF exchange or file schema definitions are an extension of the CSV headline, i.e. the csv headline is a special case of an external file schema.