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Hi,
I have a set of changeLogs that apply changes to an existing DB. The existing
DB is tagged with version X. My master.xml script for the update changeLogs has
a precondition to check that we are running against version X. This seems to
work OK. At the end of the update, the database is tagged with version Y (using
a new dummy changeLog entry and a tag).
I have been using the doc examples for creating a dummy changeLog to tag the
previous version, i.e.
Code:
<changeSet author="MajorVersion" id="100"/>
I currently use the following structure to apply updates for build 2.0.0 over
build 1.0.0:
Code:
<preConditions>
<sqlCheck expectedResult="100"> SELECT ISNULL(MAX(id),0) FROM
databasechangelog
WHERE author='MajorVersion' </sqlCheck>
</preConditions>
<include file="update/2.0.0/111.xml"/>
<include file="update/2.0.0/116.xml"/>
<include file="update/2.0.0/123.xml"/>
<changeSet author="MajorVersion" id="200"/-->
In addition to this, I tag these update changes with tag 200.
Now - if I want to rollback these changeLogs - this isn't going to work using
the same master.xml as the preconditions will now fail.
Some questions:
1) How would you recommend I structure the files so that the rollback
functionality works on a DB tagged with a newer version? A rollback is only
likely to be run after a full update has completed. I could create a
rollback.xml in each major version folder which includes the same files in the
master.xml, but has an updated precondition. Is there best-practice in this
area?
2) What's the value of using a dummy changeLog (setting MajorVersion = 100)
rather than using just LiquiBase's own tag functionality?
Thanks!
Ben
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