Database Migration from one version to another using Liquibase - database-migration

Question

I rolled out the first version of application and a Postgres server is set up for the same.
I am planning to roll out my second version of my application which has structural changes in my tables.
For example : I had App table with a column called version , now I have another column called releaseVersion and I have to apply alter to add this column.In such a case, how can I use liquibase to generate/apply the migration script?
Is liquibase capable of such migration.?
In short, for my first version I created my table using the DDL
CREATE TABLE App (version varchar); // I manually generated this using liquibase offline mode and my metadata.
Now I have my db with above column.
And I need to generate the alter to add column using liquibase. Something like this
ALTER TABLE App ADD releaseVersion varchar;
Is it possible using Liquibase as it is the industry standard for migration.
I used liquibase:diff, but it is only capable of creating the difference changelog from two databases (target db and base db). In my case, there is only a production database.

Answer 1

Yes, it's possible.
Create a changeSet like:
<changeSet author="foo" id="bar">
<preConditions onFail="MARK_RAN">
<and>
<columnExists tableName="App" columnName="version"/>
<not>
<columnExists tableName="App" columnName="releaseVersion"/>
</not>
</and>
</preConditions>
<renameColumn tableName="App" oldColumnName="version" newColumnName="releaseVersion" columnDataType="varchar(100)"/>
</changeSet>
and apply it, using liquibase update command.
If you need to just add a new column, then your changeSet will look like this:
<changeSet id="foo" author="bar">
<preConditions onFail="MARK_RAN">
<not>
<columnExists tableName="App" columnName="releaseVersion"/>
</not>
</preConditions>
<addColumn tableName="App">
<column name="releaseVersion" type="varchar(100)"/>
</addColumn>
</changeSet>