10.2.2.2 Tabular Refined Message Information Model

Exhibit 10-1, at the end of this chapter, is an example of the tabular version of the Refined Message
Information Model shown in. It has two major sections:

· The information model section, on the left, lists the information model entities (classes, associations, and attributes), one per row.

· The constraints and defaults section states specific constraints on the information model entities that will be applied to all message formats that are in Hierarchical Message Definitions derived from the Refined Message Information Model. Some of the constraints are also a part of the Message Information Model, although they may be tightened in the Refined Message Information Model. Many of the constraints are not UML constructs; they apply specifically to the HL7 messages defined based on the Refined Message Information
Model.

Some column headings in the constraints and defaults section contain the number sign. This indicates that the value for a given cell can be stated in a separate list of constraints, defaults and comments that accompanies the Refined Message Information Model and its associated Hierarchical Message Definitions.

The columns that compose these sections are defined below.

10.2.2.2.1 Information Model Section

• Row Number. This column is the row number in the spreadsheet that is used to generate the tabular
  format. It is useful during discussions about the spreadsheet.
• Row type. This column identifies the kind of information model entity that the row represents. The
  possible values are:

  rmim always the first row of the table, identifies the particular Refined Message Information Model in the nomenclature of the HL7 Repository

  class identifies a “class” in the Refined Message Information Model attr identifies an attribute of the “class” that is most directly above this row

  attr identifies an attribute of the “class” that is most directly above this row

  assoc Identifies an association leading from the class that is most directly above this row

  stc subtype constraint: this row corresponds to a subcomponent of the row above; it would not normally be included in an Refined Message
  Information Model, but it is included in order to be able to state a constraint on the subtype. This is explained in 10.2.2.4.

  It is natural to believe that every row identified with assoc has a corresponding assoc row under the row that represents the distal class of the association. However, this is not always true. Where the committee has determined that the association will only be traversed in one direction the corresponding assoc row will not be present.

• Class or Property. This column contains the information model name of the entity that is described by the row. The term property is used to lump together attributes and associations. This is because they will be treated in a very similar manner in the Hierarchical Message Definition. In an rmim row, this column contains the identifier of the parent Message Information Model.
• Short name. This is an abbreviated form of the name of the information model entity that will be used to tag the corresponding message elements in ITS-specific syntaxes that use tags. In an rmim row, this column contains the name of the parent Message Information Model.
• Inherited from. This is the class where the property (attribute or association) appears in the Message Information Model. The column is only filled in when the property appears in a different class in the Message Information Model. See 10.2.2.3. In an rmim row, this column contains the name of the Refined Message Information Model.
• Message Element Type. For attributes, this is the data type of the attribute. For associations, this is the name of the distal class.

6.2.2.2.2 Overview of defined data types

The following table tries to give a short overview of the defined data types that are commonly assigned to attributes. This table is neither complete nor detailed enough to provide anything more than a coarse overview. The complete and detailed definition of HL7 data types is found in the HL7 Version 3 Data
Type Specification. The RIM also contains a special subject area where data types are represented as information model classes.

Table 4. Defined Data Types

Name	Symbol	Description
Boolean	BL	The Boolean type stands for the values of two-valued logic. A Boolean value can be either true or false.
Character String	ST	Used when the appearance of text does not bear meaning, which is true for formalized text and all kinds of names. Do not use this data type for attributes intended to contain free text. Scarcely any attribute will be declared directly as a Character String.
Encapsulated Data	ED	Can convey any data that is primarily meant to be shown to human beings for interpretation. Whenever attributes should contain text entered and shown to users, the Encapsulated Data type should be used, not the plain character string type. Encapsulated Data can be any kind of text, whether unformatted or formatted written language or other multi-media data. Instead of the data itself, an ED may contain only a reference (URL).
Instance Identifier	II	Used to uniquely identify some individual entity, a piece of data or a real world entity. Examples are medical record number, placer and filler order id, service catalog item number, etc.
Telecommunication Address	TEL	A telephone number or e-mail address specified as a URL. In addition this type contains a time specification when that address is to be used, plus a code describing the kind of situations and requirements that would suggest that address to be used (e.g., work, home, pager, answering machine, etc.)
Code Value	CV	Exactly one symbol in a code system. The meaning of the symbol is defined exclusively and completely by the code system that the symbol is from. Used primarily for technical concepts, concepts which is crucial to HL7 operations, and concepts which are defined or adopted under the discretion of HL7.
Concept Descriptor	CD	A descriptor for a real world (“natural”) concept, such as a finding, a diagnosis, or of any semantic field, that is not under the sole discretion of HL7. A given concept may be expressed in multiple terms where each term is a translation of some other term, or is a (re-)encoding of the original human readable text, that can also be sent in this data type. This data type is suitable for multi-axial code systems.
Integer Number	INT	Integer numbers are precise numbers that are results of counting and enumerating. Integer numbers are discrete, the set of integers is infinite but countable. No arbitrary limit is imposed on the range of integer numbers. Two special integer values are defined for positive and negative infinity.
Real Number	REAL	Fractional numbers as approximations to real numbers. Fractional numbers occur whenever quantities of the real world are measured or estimated, or where quantities are the result of calculations based on other floating point numbers. This type preserves the precision in terms of significant digits.
Physical Quantity	PQ	A dimensioned quantity expressing the result of a measurement. Consists of a floating point value and a physical unit. Physical Quantities should be preferred instead of two attributes expressing a number and a unit separately. Physical quantities are often constrained to a certain dimension. This can be by specifying some unit representing the dimension (e.g., m, kg, s, kcal/d, etc.)
Monetary Amount	MO	The amount of money in some currency. Consists of a value and a denomination (e.g., U.S.$, Pound sterling, Euro, Indian Rupee).
Point in Time	TS	A scalar defining a point on axis of natural time.
General Timing Specification	GTS	A data type used to specify the timing of events. Every event spans one time interval (occurrence interval), i.e., a continuous range of natural time between a start-point and an end-point in time. A repeating event is timed through a sequence of such occurrence intervals. Such timings are often specified not directly as a sequence of intervals but as a rule, e.g., “every other day (Mo – Fr) between 8:00 and 17:00 for 10 minutes.” GTS is treated as a primitive data type (like TS) where there is a special syntax for specifying time of day, day of week, repetition pattern, etc.
Ratio	RTO	A ratio quantity is a quantity that comes about through division of any numerator quantity with any denominator quantity (except zero). Ratios occur in laboratory medicine as “titers”, i.e., the maximal dissolutions at which an analyte can still be detected. Other Ratios are price expressions, such as dollar per gram.
Postal and Residential Address	AD	The main use of such declared data is to be printed on mailing labels (postal address,) or to allow a person to physically visit a location (residential address). The difference between postal and residential address is whether or not there is just a post box.
Person Name	PN	Used for one full name of a natural person. Names usually consist of several name parts that can be classified as given, family, nickname etc. This data type is intended to be used only in the Person_name class. Instead of directly using this data type for an attribute of another class, one should consider drawing an association to the Person_name class.
Organization Name	ON	Used to name an organization. Similar but simpler than the name of a natural person
Any type	ANY	Used where data of any data type can be sent. This data type must not be used except in very special cases where it needs extensive documentation as to how this can be used interoperable. Currently there is only one use for the ANY data type (i.e., the Observation.value). An attribute of ANY data types can be constrained in subordinate models (r-MIM, HMD).

Table 5. Generic (Parameterized) Data Types

Name	Symbol	Description
Set Collection	SET	A collection of values of any type T without a specifying an order among the elements.
List Collection	LIST	An ordered set of values of any type T.
Bag Collection	BAG	An unordered set of values of any type T where each value can occur more than once (rare).
Interval	IVL	Ranges (intervals) of values of type T. An interval is a set of consecutive values of any ordered data type, such as, integer, floating point, point in time, physical quantity, monetary amount, and ratio.) Intervals should be preferred instead of two attributes expressing a start and an end separately.
Uncertain value using probabilities	UVP	A nominal value with a probability number indicating the level of certainty for the value to apply in the given context.
Parametric probability distribution	PPD	A probability distribution used to indicate certainty (accuracy) of a quantitative value. Allows specifying a distribution type and applicable parameters. All distribution types have the parameters mean and standard distribution. The mean is the value that would be reported if no probability distribution were available.