Substituting Properties in Changelogs

Liquibase allows a dynamic substitution of properties in your changelog. The tokens to replace in your changelog are described using the ${property-name} syntax.

Uses

By substituting values for replacement tokens in the format of ${property-name}, you can use the same changesets to reflect small environmental changes.

For example, your tablespace name in Oracle may differ from environment to environment, but you want to only write one create table changeset that can be used in all your environments.

Using property substitution in your changelog

You can set property values in Liquibase in several ways. Liquibase assigns these values in the following order:

  1. As an attribute passed to your Liquibase runner. See the Ant, Maven, or Servlet Listener documentation for more information on how to pass them.
  2. As a JVM system property. See JAVA_OPTS Environment Variable for more information.
  3. As an environment variable. See Liquibase Environment Variables for more information.
  4. As a CLI attribute, if executed from the command line.
  5. In the parameters block (property element of the DATABASECHANGELOG table itself).

Once a property has been set, it cannot be changed. Also, only the first definition is used, others are skipped.

Note: If the content of ${property-name} does not match a property, it is left as-is and it is not removed. The supported format includes alphanumeric characters, +, -, . , and _.

Note: If you do not want to replace an otherwise matching ${property-name} expression, add : to the beginning of the expression. An expression of ${: property-name} will always be converted to ${property-name} regardless of whether property-name is defined.

Nested properties

Name Description Required for Supports Multiple allowed?
<property> Defined before changesets in the changelog Substituting portions of a changeset during runtime All supported changeset tokens No. Property names are unique and can only be set one.

Available attributes

Attribute Description
name The name of the parameter. Required if file is not set
value The value of the property. Required if file is not set
file The name of the file from which the properties should be loaded. It will create a property for all properties in the file. The content of the file must follow the Java properties file format.
relativeToChangelogFile The relativeToChangelogFile attribute is used in conjunction with the file attribute to allow Liquibase to find the referenced file without having to configure search-path.

The default for relativeToChangelogFile remains FALSE for backwards compatibility.
context Contexts in which the property is valid. Expected as a comma-separated list.
dbms

Specifies which database type(s) a changeset is to be used for. See valid database type names on Supported Databases. Separate multiple databases with commas. Specify that a changeset is not applicable to a particular database type by prefixing with !. The keywords all and none are also available.

global Boolean. The attribute defines whether the property is global or limited to the actual DATABASECHANGELOG. Default: true.