The effectiveTime (field) andfields in theenable the use of a "log style" append-only data model to track all changes to each, providing full traceability. Once released, a row in any of these files will always remain unchanged. Historic data is supplied in thedating back to the first release informat in 2002.

In order to change the properties of a current(and, therefore, to create a new version of it), a new row is added to the applicable file, containing the updated fields, with thefield set to true and the timestamp in the effectiveTime (field) field indicating the nominal date on which the new version was released.

To inactivate aa new row is added, containing the same data as the final valid version of thebut with thefield set to false and the timestamp in the effectiveTime (field) field indicating the nominal date of the release in which the final version ceased being valid.

Where editorial policy does not allow a particular property of ato be changed whilst keeping the sametheas a whole is inactivated (as described above), and a new row added with a new id, the effectiveTime (field) set to the nominal date of the release in which this version of thebecame valid, and thefield set to true.

It is thus possible to see both the current values and any historical values of aat any point in time.

Content will not be future dated with respect to the release that it appears in, although a release itself may be released a few days before its nominal release date. Where there is a business requirement for specifying a future activation date for somethis may be modeled using
The following example demonstrates how the history mechanism works on the Concept file, but the same rules apply equally well to theandmember files. In this example, theassociated with the moduleId (field) and definitionStatusId (field) have been shown in place of their SCTID (data type) values.

A new(101291009) is added on the 1st July 2007:

|Module 1|

900000000000074008|Primitive|

In the next release (on 1 st January 2008), theis moved from |Module 1| to |Module 2|. Because the moduleId field is not immutable, themay be updated simply by adding a new record with the same Id.

|Module 1|

900000000000074008|Primitive|

|Module 2|

900000000000074008|Primitive|

In the next release (on 1st July 2008), theis changed from beingto being

|Module 1|

900000000000074008|Primitive|

|Module 2|

900000000000074008|Primitive|

|Module 2|

900000000000073002|Defined|

In the next release (on 1 st January 2009), theis deactivated:

|Module 1|

900000000000074008|Primitive|

|Module 2|

900000000000074008|Primitive|

|Module 2|

900000000000073002|Defined|

|Module 2|

900000000000074008|Primitive|

Notes

1. At no stage in this process are previously written records ever amended. Once a record has been released in ait will continue to be released in exactly the same form in future

2. Changes are only recorded at the point of release in theIf arecord is changed a number of times between releases (during an edit and review process), only the most recently amended record will be appended to thenot individual records showing each separate edit to the released

3. In the last example, as well as inactivating the concept (active=0), the definitionStatusId (field) is changed from

   900000000000073002|Defined|

   to

   900000000000074008|Primitive|

   . In practice this change is not essential since the value of data columns is ignored when ais inactive. Although the change is unnecessary and insignificant, it typically occurs since all the relationships of an inactive concept must also be inactive, and as a result, from the perspective of the authoring environment the concept cannot be regarded as

   900000000000073002|Defined|

   .

Related Links

• 3.1.4.1. Component features - History