Liquibase adding default value and not null constraint

Question

I am bit new to Liquibase. I came across a scenario where in one changeSet it is trying to add a default value first and not null constraint next to that.

But problem over here is both <addDefaultValue/> and <addNotNullConstraint/> tags have a default value attributes so eventually I am ending up with an exception.

Below is the changeSet that I have,

<changeSet id="f3047816-2d48-4341-a4ce-deface083cea" author="MineStar" failOnError="true">
  <preConditions onFailMessage="Ignored AlterColumn for REHANDLE of table LOCATION as column does not exist or already has a NOT NULL constraint." onFail="MARK_RAN">
    <columnExists tableName="LOCATION" columnName="REHANDLE"/>
    <ext:columnIsNullable tableName="LOCATION" columnName="REHANDLE"/>
  </preConditions>
  <comment>AHS-1373: AlterColumn LOCATION.REHANDLE - nullability changed from true to false - defaultValue changed from 'null' to '0'</comment>
  <addDefaultValue columnName="REHANDLE" columnDataType="BOOLEAN" defaultValueNumeric="0" tableName="LOCATION"/>
  <addNotNullConstraint columnName="REHANDLE" defaultNullValue="0" columnDataType="BOOLEAN" tableName="LOCATION"/>
</changeSet>

Here one more strange thing I could see is if I rearrange the order of adding default value and not null constraints tags I won't get any exception that is first adding not null constraint and then default value like below. But I should not do that as it effects checksum in database all that I can do is adding a new changeSet to resolve the exception.

<addNotNullConstraint columnName="REHANDLE" defaultNullValue="0" columnDataType="BOOLEAN" tableName="LOCATION"/>

<addDefaultValue columnName="REHANDLE" columnDataType="BOOLEAN" defaultValueNumeric="0" tableName="LOCATION"/>.

Answer 1

There is a difference between the defautlNullValue in addNotNullConstraint and defaultValueNumeric in addDefaultValue. Using addDefaultValue just sets a default value for future rows inserted into the column but defaultNullValue in addNotNullConstraint will cause liquibase to generate an additional SQL statement of update location set rehandle=0 where rehandle is null to change the value of already existing rows so that a null constraint can be added.

I would think either order would work fine, what exception were you seeing?