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The Data Dictionary is organised into Data Classes.

A Data Class, or a table, is a collection of one or more Data Elements and/or child Data Classes.

Image RemovedThe definitions, including rules and constraints for valid values for all Data Elements are defined using the following metamodel:

• Name: the name of the data class

• Description: a description of the data class

• Data Elements: data elements contained with the class

• Child Classes: data classes contained within the class

• Cardinality: the number of times a data class can occur within a group

• Level: Could, Should, Must

• Metadata: any additional metadata associated with the data class

• Relationships: related data classes or elements (which may reside in another standard)

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A Data Element is the logical definition of a unit of data such as:

• a column in a database table 

• a field in a form 

• an element in an XML schema

The definitions, including rules and constraints for valid values for all Data Elements are defined using the following metamodel:

• Name: the name of the data element

• Description: a description of the data class

• Data type: the constraint on the data element e.g. integer, string

• Cardinality: the number of times an lement can occur within a group

• Level: Could, Should, Must

• Metadata: any additional metadata associated with the data element

• Relationships: related data classes or elements (which may reside in another standard), including child/parent relationships

Data Elements contain a Data Type which specifies the input value of the element e.g. varchar or datetime.

• Name: the name of the data type

• Description: a description of the data type, if applicable

• Type

  • Simple - e.g. varchar, string, integer

  • Enumerated - a list of possible values

  • Reference

• Relationships: to other data types or data element