MDDL: Content - Terminology

Shorthand
The convention of "shorthand" within MDDL allows simplification of the MDDL Instance Document after inheritance has been applied. Applied to the MDDL XML-based schema: Once inheritance has been applied and all qualifiers and other properties within a particular element have been moved up higher in the hierarchy, thus leaving only the atomic element (for example, 'mdDecimal' for property 'last') then the 'mdDecimal' can be removed and the value is contained within the element.

Shorthand requires that the MDDL W3C Schema be implemented using mix-mode elements (i.e. sometimes an element has a value and sometimes it does not). Implementations need to be aware that a property may have EITHER a value OR it may have children - NOT BOTH.

Example WITHOUT inheritance:
<ask>
  <last>
    <mdDecimal>102.34</mdDecimal>
    <currency>JPY</currency>
  </last>
  <open>
    <mdDecimal>102.21</mdDecimal>
    <currency>JPY</currency>
  </open>
</ask>

Example WITH inheritance:
<ask>
  <currency>JPY</currency>
  <last>
    <mdDecimal>102.34</mdDecimal>
  </last>
  <open>
    <mdDecimal>102.21</mdDecimal>
  </open>
</ask>

Example WITH inheritance AND shorthand:
<ask>
  <currency>JPY</currency>
  <last>102.34</last>
  <open>102.21</open>
</ask>

In this example, the 'last' and 'open' properties (after inheritance has promoted the 'currency') are left with the atomic type element 'mdDecimal'. As this is the ONLY child of 'last' and 'open' then shorthand can be applied.