Enumerated Data Type
Enumerated Data Types (EDTs) are data types that can only hold values from a constrained set such as 1, 2, 3 or A, B, C.
EDTs (examples above are Hair Colour, Sex and Vehicle Model) are managed within a Context.
All information systems have a set of data types (whether implicit or explicitly defined) that describe the data items (e.g. screen fields, combo-boxes, database columns) in the system. The simple data types (such as string, integer, date etc) do not require any particular configuration controls but the enumerated data types can pose a serious headache particularly when systems must interchange information with others. Agreement on what values are valid within each field of an interface is critical in order to avoid misinterpretation of messages. Messages received by an application that doesn't understand them or misinterprets them is one of the principal reasons for business system failure and consumes a significant proportion of the application support budget of most organizations.
Listpoint provides a single central repository where data standards owners and application developers can share the precise detail of their enumerated data types and hitch them up where appropriate to shared standard Code Lists so they can be alerted when new enumerations are added that may affect their Context.
Each Enumerated Data Type (EDT) belongs to a single Context. It has a local name that makes sense or conforms to naming standards within its owning Context. It also contains a template defining from where and how its CVs are derived.
The template has the following properties:
|Source Code List||The name of the (versioned) Code List from which Constrained Values are drawn|
|Level||The number of the Level within the Code List that contains the required CVs. Usually #1 but may be #2 or #3 if the Code List is a hierarchy.|
|Length||(Optional) The maximum length of value that can be handled by this Context. This should be the physical limit rather than the maximum length typically received. This is useful information when Code List editors are assessing whether an increase in code length will adversely impact any consuming applications.|
|Element Value Policy||Whether Codes or Meanings are required as the CVs|
|Effective Date Policy||How to treat obsolete codes etc|
|Parent Code Filter||A filter to return just part of the indicated CV Set/Level|
|Parent Data Type Name||(Optional) The name of a data type in this Context that exposes the full set of possible Parent Codes for this EDT. This helps an application identify, for instance, the right group of EDTs needed to populate a cascaded set of combo-boxes|
|Usage Guidelines||Optional hints from the context steward to consumers on when to use this EDT etc|
|Null Code||The optional code value that should be used to signify that no code is applicable e.g. 9999 or 0 or NONE|
|Null Meaning||How the Null Code is presented in a user interface e.g. "Not applicable", "Not specified", "N/A" etc|