2 preconditions in one liquibase changeset

Question

Is it possible to create two preconditons for single elements of a changeset? Like generating a column if the changelog file is run at a SQL Server database and generating another column if the changelog file is run at an Oracle database. In a way like this for example:

<changeSet author="Me" id="1528876614155">
 <createTable tableName="ELECTRICITY_PRODUCTS">

   <preConditions onFail="MARK_RAN" onSqlOutput="TEST">
        <dbms type="mssql" />
        <column autoIncrement="true" name="EP_ID" type="NUMBER">
   </preConditions>
   <preConditions onFail="MARK_RAN" onSqlOutput="TEST">
        <dbms type="oracle" />
        <column autoIncrement="false" name="EP_ID" type="FLOAT">
   </preConditions>
 </createTable>
</changeset>

why don't you create two separate changeSets with dbms attribute? — bilak, Aug 10 '18 at 12:37
Because I have many changesets which have to be changed often and then it would be much more work. — Mad Scientist, Aug 10 '18 at 13:23

score 2 · Accepted Answer · answered Aug 10 '18 at 13:54

It's not possible to create column inside condition.

If I understand your problem, then you have two (maybe more) options:

Separte the changeSets for each dbms

Create property for dbms and use them like:

<property dbms="oracle" name="autoincrement" value="true" />
<property dbms="oracle" name="autoincrementType" value="NUMBER" />
<property dbms="mssql" name="autoincrement" value="false" />
<property dbms="mssql" name="autoincrementType" value="FLOAT" />


<changeSet id="create_a_table" author="system">
    <createTable tableName="a_table">
        <column name="a_column" autoIncrement="${autoincrement}" type="${autoincrementType}" />
    </createTable>
</changeSet>

I didn't tested that, it's just idea how to solve the problem.

score 0 · Answer 2 · answered Aug 10 '18 at 13:59

This seems to be not possible but another good solution is to create changesets for these single elements. In this example it could be:

<changeSet author="Me" id="1528876614155">
    <createTable tableName="DAILY DATA">
        <column name="ID" type="NUMBER"/>
    </createTable>
</changeset>

<changeSet author="Me" id="1528876614156">
    <preConditions onFail="MARK_RAN" onSqlOutput="TEST">
        <dbms type="oracle" />
    </preConditions>
    <addColumn tableName="DAILY_DATA">
        <column name="VALUE" type="NUMBER"/>
    </addColumn>
</changeset>
<changeSet author="Me" id="1528876614157">
    <preConditions onFail="MARK_RAN" onSqlOutput="TEST">
        <dbms type="mssql" />
    </preConditions>
    <addColumn tableName="DAILY_DATA">
        <column name="VALUE" type="NUMBER"/>
    </addColumn>
</changeset>

2 preconditions in one liquibase changeset

2 Answers2