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Liquibase Commands: diffChangeLog

The diffChangeLog command provides you with:

  • Information containing differences between two databases; specifically, the diffChangeLog command points out the differences in general and generates changes to resolve most of them.
  • A changelog file containing deployable changeSets.

Uses

The diffChangeLog command is typically used when you want to create a deployable changelog to synchronize multiple databases. The diffChangeLog command also provides more information about:

  • Missing objects in your database
  • Changes made to your database
  • Unexpected items in your database

Running the diffChangeLog Command

To create a diff changelog:

  • The first option is to run the diffChangeLog command and pass the parameters needed for your source database and target database.

As an example you can run the following:

liquibase
--changeLogFile=dbchangelog.xml
--outputFile=mydiff.txt
--driver=oracle.jdbc.OracleDriver
--classpath=ojdbc14.jar
--url="jdbc:oracle:thin:@<IP OR HOSTNAME>:<PORT>:<SERVICE NAME OR SID>"
--username=<USERNAME>
--password=<PASSWORD>
diffChangeLog
--referenceUrl="jdbc:oracle:thin:@<IP OR HOSTNAME>:<PORT>:<SERVICE NAME OR SID>"
--referenceUsername=<USERNAME>
--referencePassword=<PASSWORD>

See the snapshot command documentation for an example of using a snapshot file as one of the databases being used in the command.

Note: When running diffChangeLog against two different databases, the class path property should reference both .jar files. Use the path separator that is correct for your operating system (a semicolon on Windows, a colon on Mac or Linux). Example: classpath: ojdbc7.jar:postgresql-42.2.8.jar

  • Alternatively, configure the liquibase.properties file to include your driver class path, URL, and user authentication information for both databases. Run the following command:
liquibase --changeLogFile=file_name.xml diffChangeLog

Note: Replace file_name.xml, with your filename and extension format. If you specify a file name that already exists, Liquibase will append your changes to the existing file.

For information on how to configure your liquibase.properties file, view the Creating & Configuring your liquibase.properties File topic in the knowledge base.

Output

The diffChangeLog command produces a list of all Objects and creates a changelog with a list of changeSets.

Liquibase Community diffChangeLog categories:

  • Catalog
  • Column
  • Foreign Key
  • Index
  • Primary Key
  • Schema
  • Sequence
  • Procedure
  • Unique Constraints
  • View

Example

Console Output Example 
Liquibase Pro 3.8.1 by Datical licensed to Liquibase Pro Customer
Liquibase command 'diffChangeLog' was executed successfully.


Additional Functionality with Liquibase Pro

While Liquibase Community stores all changeSets in a changelog, Liquibase Pro creates a directory called Objects and places the directory at the same level as your changelog. The Objects directory contains a subdirectory for each of the following stored logic types:

  • checkconstraint
  • package
  • packagebody
  • function
  • trigger
  • synonyms

Note: that not all database platforms support all of these types.

Example

Pro diffChangeLog sample file 
<?xml version="1.0" encoding="UTF-8"?>
<databaseChangeLog
  xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:pro="http://www.liquibase.org/xml/ns/pro"
  xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
         http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-3.8.xsd">
    <changeSet author="Administrator (generated)" id="1571345362466-8">
           <pro:createTrigger disabled="false" path="objects/trigger/TS_T_EXEMPLAR_SEQEXEMPLAR.sql" relativeToChangelogFile="true" tableName="T_EXEMPLAR" triggerName="TS_T_EXEMPLAR_SEQEXEMPLAR"/>
       </changeSet>
       <changeSet author="Administrator (generated)" id="1571345362466-9">
           <pro:createTrigger disabled="false" path="objects/trigger/ORDERS_BEFORE_INSERT4.sql" relativeToChangelogFile="true" tableName="orders" triggerName="ORDERS_BEFORE_INSERT4"/>
       </changeSet>
       <changeSet author="Administrator (generated)" id="1571345362466-10">
           <pro:createTrigger disabled="false" path="objects/trigger/ORDERS_BEFORE_INSERT2.sql" relativeToChangelogFile="true" tableName="orders" triggerName="ORDERS_BEFORE_INSERT2"/>
       </changeSet>
       <changeSet author="Administrator (generated)" id="1571345362466-11">
           <pro:createTrigger disabled="false" path="objects/trigger/ORDERS_BEFORE_INSERT.sql" relativeToChangelogFile="true" tableName="orders" triggerName="ORDERS_BEFORE_INSERT"/>
       </changeSet>
       <changeSet author="Administrator (generated)" id="1571345362466-12">
           <createView fullDefinition="true" path="objects/view/OREDERS_VIEW.sql" relativeToChangelogFile="true" viewName="OREDERS_VIEW"/>
       </changeSet>
       <changeSet author="Administrator (generated)" id="1571345362466-13">
           <pro:createTrigger disabled="false" path="objects/trigger/ORDERS_BEFORE_INSERT3.sql" relativeToChangelogFile="true" tableName="orders" triggerName="ORDERS_BEFORE_INSERT3"/>
       </changeSet>
       <changeSet author="Administrator (generated)" id="1571345362466-14">
           <createProcedure path="objects/storedprocedure/P_CUSTOMER_HAS_NUM_FILM.sql" procedureName="P_CUSTOMER_HAS_NUM_FILM" relativeToChangelogFile="true"/>
       </changeSet>
       <changeSet author="Administrator (generated)" id="1571345362466-15">
           <createView fullDefinition="true" path="objects/view/V_CUSTOMER_HAS_FILM.sql" relativeToChangelogFile="true" viewName="V_CUSTOMER_HAS_FILM"/>
       </changeSet>
       <changeSet author="Administrator (generated)" id="1571345362466-16">
           <createProcedure path="objects/storedprocedure/SP_CUSTOMER_SOCIAL_ACCTS.sql" procedureName="SP_CUSTOMER_SOCIAL_ACCTS" relativeToChangelogFile="true"/>
       </changeSet>
       <changeSet author="Administrator (generated)" id="1571345362466-17">
           <pro:createTrigger disabled="false" path="objects/trigger/TRI_BORROWING.sql" relativeToChangelogFile="true" tableName="T_BORROWING" triggerName="TRI_BORROWING"/>
       </changeSet>
       <changeSet author="Administrator (generated)" id="1571345362466-18">
           <pro:createTrigger disabled="false" path="objects/trigger/TRU_BORROWING.sql" relativeToChangelogFile="true" tableName="T_BORROWING" triggerName="TRU_BORROWING"/>
       </changeSet>
       <changeSet author="Administrator (generated)" id="1571345362466-19">
           <pro:createTrigger disabled="false" path="objects/trigger/TSU_T_EXEMPLAR_SEQEXEMPLAR.sql" relativeToChangelogFile="true" tableName="T_EXEMPLAR" triggerName="TSU_T_EXEMPLAR_SEQEXEMPLAR"/>
       </changeSet>
       <changeSet author="Administrator (generated)" id="1571345362466-20">
           <pro:createFunction functionName="F_CUSTOMER_HAS_NUM_FILM" path="objects/function/F_CUSTOMER_HAS_NUM_FILM.sql" relativeToChangelogFile="true"/>
       </changeSet>
</databaseChangeLog>

Note: Liquibase does not currently check datatype length.