This quick tour example is designed to build on the XML Authority quick tour where you created a price list schema. Once you have created this schema, this exercise will show you how to design a MetaSchema, allowing you to adorn your schema with additional meta-data. See Building a MetaSchema for an overview of this process.
Before we begin: MetaSchemas are a way to develop a template in XML Authority for the capture and recording of additional information about the schema within the schema itself. This facilitates the integration of the schema into your applications and allows the association of additional meta-data with components of the schema. An obvious use of this ability would be to associate relational database mappings with elements and attributes within the schema. MetaSchemas, specifically adorned schemas, are based on the XDR (XML-Data Reduced) dialect of schemas because the XDR schema language has an open content model which permits the adornment of schemas with additional data structures. Other dialect-neutral ways to capture schema level information are emerging and are presented in MetaSchemas- Concepts and Overview.
The Example
In this example, you will first design the template for the MetaSchema using XML Authority. Once this template is in place and you save it, you will be creating a sub-dialect of XDR schemas with its own file extension. Then you will convert the price list DTD to the newly created schema format and adorn it with additional information.
During this quick tour you will be creating a template which will then change the user interface for schemas in the new schema format. The template and associated user interface changes are stored in the extensions folder created during the installation of XML Authority.
Creating the Template
fig 1.1 - Welcome to XML Authority
This will open the application and default to the Element Types pane with schema, element, and attribute already showing in the Element Type column.
The MetaSchema you are going to create will create additional columns and fields within the user interface of XML Authority and it is in the Element Type columns that you define what these new columns will be. This example will allow you to capture basic schema level information and input mappings to database tables and rows at an element and attribute level within the schema.
fig 1.2 - Auto Create prompt
fig 1.3 Finished MetaSchema template
fig 1.4 Converted schema with new custom interface.
This exercise provides an example of creating a MetaSchema template and converting a DTD to this new format. The example illustrates just one potential use of MetaSchemas and shows you how to use XML Authority to build templates to take advantage of this schema adornment process. The examples of author, change_date, db_table, and db_row are just possible choices in meta-data categories and you should evaluate your specific needs. The user interface changes recorded by creating the MetaSchema template allow company wide sharing of schema design and allow consistent input of meta-data.
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