1. A method of making a data representation of transaction-tax-related information of a transaction in a database or a data file which can be processed by a computer, the transaction being represented by a transaction document having one or more transaction-document lines, the transaction-tax-related information associated with which has one or more taxation levels, the method comprising: arranging data items representing the transaction-tax-related information in the database or data file according to a data schema for representing transaction-tax information for different jurisdictions, including jurisdictions with different kinds and numbers of taxation levels; wherein the data schema provides a taxation-line entity for each transaction-document line; the data schema provides a taxation-line-item entity, related to the taxation-line entity, for each taxation level of a transaction-document line; and wherein an attribute of the taxation-line-item entity is used to indicate the kind of taxation level represented by the taxation-line-item entity.