Using XML with Legacy Business Applications

If, How, and Where to Validate

This is a fundamental choice, and you'll benefit by making it as early as possible. We'll assume in this discussion that you're going to use a standard DOM or SAX API that offers validation against W3C schemas. A major choice you need to make is whether or not you are going to have the API validate documents against a schema. This is primarily of concern for documents that your application will consume, but it may also relate to documents that your application will produce. A related decision is the choice of schema, which we'll talk about shortly; you can pick a standard (if you can find an appropriate one) or you can create your own. If you do create your own, you have flexibility about how strictly you write ...