liquibase-envers-support

This project contains a Liquibase extension that will allow you to automatically add a given changeSet after a <tagDatabase> changeSet. It is primarily useful for adding a new Envers revision after you've tagged your database.

By default this extension does nothing

This extension needs to be enabled before it will actually do anything. The extension is enabled by defining a template changeSet. All <tagDatabase> changeSets before the template changeSet will be left alone. So, effectively, this extension will start working after the template changeSet.

Defining the template changeSet

A template changeSet is define much like a normal changeSet, only with a specific author. The author needs to be "liquibase-envers-support plugin". The rest of the template changeSet is copied and placed below a <tagDatabase> changeSet by the extension. Of course, the template changeSet is removed from its original location (because it's a template).

Placeholders

In the template, you can use placeholders. These are replaced by actual values by the liquibase-envers-support extension. The following placeholders are available:

• @PREVIOUS_VERSION@: This will be replaced by the value of the previous <tagDatabase> tag.
• @CURRENT_VERSION@: This will be replaced by the value of the next <tagDatabase> tag. If there is no next <tagDatabase> tag, the value will default to 'develop'.

Template changeSet example

<changeSet context="context" dbms="postgresql" id="Previous DB version was @PREVIOUS_VERSION@; next DB version is @CURRENT_VERSION@" author="liquibase-envers-support plugin">
    <insert tableName="REVINFO">
        <column name="ID" valueComputed="${hibernateSequenceNextVal}"/>
        <column name="TIMESTAMP" valueComputed="${now_timestamp}"/>
        <column name="USERNAME" value="Liquibase (version @CURRENT_VERSION@)"/>
    </insert>

    <rollback>
        <delete tableName="REVINFO">
            <where>ID = (SELECT MAX(ID) FROM REVINFO WHERE USERNAME = 'Liquibase (version @CURRENT_VERSION@)')</where>
        </delete>
    </rollback>
</changeSet>

By design, sometimes the template changeSet is not added

When the very last changeSet is a <tagDatabase> changeSet, this extension will not add a copy of the template changeSet after it. This is specific to the nature of Envers revisions. (If we would add a copy of the template changeSet, it would lead to an empty Envers revision.)

Also, when there are multiple subsequent <tagDatabase> changeSets, this extension will only add a copy of the template changeSet for the first one. This is specific to the nature of Envers revision. (If we would add a copy of the template changeSet for every <tagDatabase> changeSet, it would lead to empty Envers revisions.)