<changeSet id="20121109-TRUNK-3474" author="patandre">
		<preConditions onFail="MARK_RAN">
			<columnExists tableName="concept_class" columnName="description" />
		</preConditions>
		<comment>
			Dropping not null constraint from concept_class.description column
		</comment>
		<dropNotNullConstraint tableName="concept_class" columnName="description" columnDataType="varchar(255)" />
	</changeSet>