Terminology
The MDDL documentation uses various terms that have a specific meaning within the limitations of the MDDL specification. These terms are defined here as a way to clarify the proposed meaning in reference to MDDL.
The MDDL specific terminology includes the following:
Base Type:
Each MDDL defined property has a base type defined in the vocabulary. The base type specifies the kind of value the property can contain in much the same way a type constrains a variable in most programming languages. Base types include Boolean, dateTime, Decimal, Duration, Enumeration, Positive, String, and URI.
Classification:
MDDL uses the term classification to denote the fundamental usage of a property or element. The classification identifies the predefined collection of properties that can be used to clarify the parent property.
Construct:
An MDDL construct is the collection and grouping of products and properties necessary to convey a particular reason for providing the market data.
Container:
A container is a property that is a concept, not a specific piece of data, that is clarified by other properties. It is a collection of properties rather than a property itself.
Controlled Vocabulary:
A controlled vocabulary is a list of terms intended to constrain the values a particular property may contain. A Controlled Vocabulary "scheme" only applies to a String type property.
Group:
When using the MDDL features of inheritance, it is sometimes useful to collect subsets of properties into children of a group and set the properties to be inherited in the group. A group is nothing more than a convenient packaging of properties for inheritance and has no intrinsic value itself.
Inheritance:
The inheritance feature within MDDL is similar to object oriented programming where a property can be set at a higher level in the element tree and it "inherits" down to the children and leafs. Often used in conjunction with shorthand.
Instance Document:
The term "instance document" applies to an MDDL formatted XML document that describes a specific collection of market data.
Product:
MDDL uses the term product to denote the collection of properties and the inherent relationship between those properties necessary to define a financial instrument or asset, indicator or average, or corporate action or event relevant to market data.
Property:
A property is a descriptor or modifier about a piece of data that clarifies the nature of the data. Properties hold the real content of MDDL across the full range of market data.
Scheme:
A scheme is the name for an enumerated list or controlled vocabulary. The scheme identifies which list of values are legal for a particular property.
Shorthand:
Shorthand is a convention within MDDL that permits the removal of XML tags for base types. Used in conjunction with inheritance.
