A map-set, as the name suggests, is a set of mappings. Each map is a Display Key to Data. E.g. "United Kingdom" (display key) to "UK" (data), "Germany" (key) to "D" (data).
SYNTAX
FOX uses XML Schema Enumerations for Drop Downs / Lists Of Values (LOV) on screens. They are satisfactory for simple uses, but static and inflexible for sophisticated applications.
A map-set behaves like an Enumeration LOV, but is highly dynamic in nature.
When above map-set is associated with xs:element definition and set-out on screen:
- User sees a Drop Down LOV with choices: "United Kingdom", "Germany"
- However FOX translates user input when stored in XML as follows: "UK" or "D"
Here the data value is a simple type (xs:string), but it can also be a complex collection.
Map-set data is stored in a specific XML Data structure in the module schema as shown here:
For the countries example mentioned above the data would have the following structure:
The key in a map set is always an xs:string but the data element can be of any type, including a complex type. The data for the countries example looks like this:
An example of where the data is a complex data structure is the following:
And the data:
Fox manages the map-set data structures automatically using a set of rules (details later):
- Where the XML data is stored - a Storage Location
- How the XML data is constructed - FOX meta-code
- How long the data is good for - I.E. when it needs refreshing (constructing again)
Map-sets are utilised by display widgets, fm:validate and fm:context-localise (covered later).