XML was developed to overcome the limitations of HTML, and is widely used in Internet publishing and data exchange for e-commerce. The DTD specifies which elements are allowed where in an XML document. In the first example, I start from an object model. This is the easiest solution because you can reuse the objects defined in the model. In the second example, I create a DTD from scratch.
Owner is the account owner.
An Account can have more than one Owner and an Owner can own more than one Account. The application we are interested in is Web banking. The first step in designing the DTD is to decide on the root element. The root element determines how easily we can navigate the document and access the information we are interested in. Given that we are doing a Web banking application, Owner is the logical choice as a top element.