This is for testing purposes only.  It is possible that some concept changes will be reversed and the actions 
erased from history.  

There are four pipe delimited history files in this directory.

Cumulative_history_07.10d is a direct export of the concept history table as of October 29th, 2007.  Subset_Cumulative_history_07.10d is a subset of the Cumulative_history that displays only cases where concepts have been created, merged, split, retired, or experienced a conceptname change.  These files are cumulative from the beginning of 
EVS recorded history to the given date.  All subsequent files are pulled on a monthly basis and are not cumulative.

Monthly_history_07.10d is a direct export of the concept history table from September 27, 2007 to October 29, 2007.  Subset_Monthly_history_07.10d is a subset of the Monthly_history_07.10d that displays only cases where concepts have been 
created, merged, split, retired, or experienced a conceptname change.  These history files correspond to the 
Thesaurus_07.10d baseline.  History files for previous baselines can be found in the appropriate folder under archive.

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The fields in these files are conceptcode|conceptname|editaction|editdate|referencecode|referencename

conceptcode is the unique, permanent, alphanumeric identifier of the concept

conceptname is the current text name of the concept

editaction is the activity being recorded (create, modify, split, merge, retire)

editdate is the date the activity occurred

referencecode is the identifier for a concept affected by or influencing the action, as detailed below

referencename is the current text name of the reference concept in all cases except concept name changes.  For 
these, the referencename is the old name of the current concept.



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Reference codes are recorded in the following circumstances:

Merges - 
In a merge, two concepts are merged into one.  One of the two concepts survives and the other concept is retired.  
A merge history record is written for both of the concepts with a reference code of the surviving concept and a 
retire record is written for the concept that retires.  In the case of A merging with B and A surviving, the history 
will appear as follows:
C11111|A|merge|dd-mon-yy|C11111|A
C22222|B|merge|dd-mon-yy|C11111|A
C22222|B|retire|dd-mon-yy|(null)|(null)

Splits - 
In a split, a single concept is split into two.  The original concept survives and a new concept is generated.  Two 
split records are written for the original concept with reference codes for the resulting concepts and a create history
 record is written for the new concept. In the case of A being split into A and B the history will appear as follows:
C22222|B|create|dd-mon-yy|(null)|(null)
C11111|A|split|dd-mon-yy|C22222|B
C11111|A|split|dd-mon-yy|C11111|A

Retires -
In a retirement the concept is moved from it's old location in the tree hierarchy into the Retired_Kind.  A retire 
record is written for the retiring concept with a reference code of the old superconcept.  If a concept has multiple 
superconcepts, then a retire record is written for each reference.  In the case of retiring concept A which has two 
superconcepts (B and C), the history will appear as follows:
C11111|A|retire|dd-mon-yy|C22222|B
C11111|A|retire|dd-mon-yy|C33333|C

Concept Name Changes - 
When a history record is written, the current name of the concept is recorded in the history.  We can match the 
conceptcode from the current Thesaurus against the conceptcodes in the history to determine if any conceptnames have 
changed. In the case of concept A having it's name changed to B, the history will appear as follows:
C11111|B|modify|dd-mon-yy|(null)|A