`diffChangeLog` command

The diffChangeLog command allows you to receive information on differences between two databases you are comparing and creates a changelog file containing deployable changesets.

The diffChangeLog command points out the differences in general and generates changes to resolve most of them.

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

Running the diffChangeLog command requires two URLs:

referenceURL – the source for the comparison. The referenceURL attribute represents your source database which is the starting point and the basis for the database you want to compare.
url – the target of the comparison. The URL attribute stands for your target database which you want to compare to the source database. You typically perform actions and run the commands and against this database.

To create a diff changelog:

The first option is to run the diffChangeLog command and pass the attributes 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>
				
diffChangeLog

Note: If you want to create an SQL changelog file, add your database type name when specifying the changelog file: liquibase --changeLogFile=mychangelog.oracle.sql diffChangeLog. Replace .oracle.sql with your database type. When in doubt about your database type name, check Supported Databases.

See the snapshot command topic 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, and URL 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 and configuring a liquibase.properties file topic.

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

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: Not all database platforms support all of these types.

Liquibase Pro diffChangeLog example 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 data type length.

diffChangeLog command

Uses

Running the diffChangeLog command

Output

Additional Functionality with Liquibase Pro

`diffChangeLog` command

Running the `diffChangeLog` command