Changelog Attributes
You can use attributes in your Changelog and in an individual Changeset to complete the following tasks:
- Reference other changelogs from within a changelog
- Break up your primary changelog into more manageable pieces
- Specify when, how, and under what conditions to run changes in a changeset
- Define the behavior of table columns
Syntax
An attribute's scope refers to what it affects—the entire changelog (global), a particular changeset (local), or an element nested inside a particular changeset, like a column. Most attributes have only one valid scope, but some can go in either the changelog or changeset, such as Preconditions.
You define some elements in the "header" of your changelog file or individual changesets. You nest other elements within the body of the changelog or individual changesets. For example, in an XML changelog:
<databaseChangeLog objectQuotingStrategy="LEGACY">
<changeSet author="liquibase-docs" id="createTable-example">
<createTable tableName="person">
<column name="address" type="varchar(255)"/>
</createTable>
</changeSet>
</databaseChangeLog>
In this case, objectQuotingStrategy
is an attribute whose scope is the entire changelog, changeSet
is a sub-tag, and author
is an attribute whose scope is a particular changeset.
Note: All changelog attributes use the camelCase
format.
Changelog-scoped attributes
You can apply these attributes to your whole changelog:
Attribute | Description |
---|---|
context
|
Specifies the changeset contexts to match. Contexts are tags you can add to changesets to control which changesets are executed in any particular migration run. Contexts you specify in the changelog header are inherited by individual changesets. See also: |
logicalFilePath
|
Overrides the file name and path when creating the unique identifier of changesets. It is required when you want to move or rename changelogs. |
objectQuotingStrategy
|
Controls how object names are quoted in the SQL files generated by Liquibase and used in calls to the database. Default:
|
Nested elements
You can use these tags in the body of your changelog or sometimes within another nested element:
Tag | Description |
---|---|
preConditions
|
Preconditions required to execute the changelog. If global, must be passed before the changeset is run. Preconditions are typically used for doing a data sanity check before doing something unrecoverable such as a |
property
|
The value for which to set the property. |
changeSet
|
The changesets to execute. |
include
|
Additional files containing changesets to execute. |
includeAll
|
An additional directory containing files with changesets to execute. |
modifyChangeSets
|
Include additional files using an application's native executor. |
Changeset-scoped attributes
You can apply these attributes to individual changesets:
Attribute | Description | Requirement |
---|---|---|
author
|
Specifies the creator of the changeset. Must be non-empty if the global argument strict is true . Can be empty only if strict is false . |
Required |
id
|
Specifies an alpha-numeric identifier. Note: If there are zeros in the id, it is best practice to put quotes around the id, such as "1.10". This allows all characters to be retained. |
Required |
context
|
Specifies the changeset contexts to match. Contexts are tags you can add to changesets to control which changesets will be executed in any particular migration run. |
Optional |
created
|
Stores dates, versions, or any other string of value without using remarks (comments) attributes. Since 3.5 | Optional |
dbms
|
Specifies which database type |
Optional |
failOnError
|
Defines whether a database migration will fail if an error occurs while executing the changeset. Default: |
Optional |
ignore
|
Tells Liquibase to treat a particular changeset as if it does not exist. Default: |
Optional |
labels
|
Specifies the changeset labels to match. Labels are tags you can add to changesets to control which changesets will be executed in any migration run. |
Optional |
logicalFilePath
|
Overrides the file name and path when creating the unique identifier of changesets. It is required when you want to move or rename changelogs. |
Optional |
objectQuotingStrategy
|
Controls how object names are quoted in the SQL files generated by Liquibase and used in calls to the database. Default:
|
Optional |
onValidationFail
|
Controls what Liquibase does when a changeset fails validation. Values are HALT and MARK_RAN . Default: HALT . |
Optional |
runAlways
|
Executes the changeset on every run, even if it has been run before. Default: |
Optional |
runInTransaction
|
Specifies whether the changeset can be run as a single transaction (if possible). Default: Warning: If |
Optional |
runOnChange
|
Executes the changeset when you create it and each time it changes. Default: |
Optional |
runOrder
|
Specifies whether a changeset should be run before or after all other changesets instead of running it sequentially based on its order in the changelog. Valid values are first and last . It is typically used when you want a changeset to be always executed after everything else but don’t want to keep moving it to the end of the changelog. Setting the runOrder to last will automatically move the changeset to the final place in the changeset run order. Since 3.5Note: |
Optional |
runWith
|
Specifies a native executor to run your SQL ( |
Optional |
runWithSpoolFile
|
Specifies a spool file to send output to when you deploy a particular changeset. |
Optional |
Sub-tags
You can nest these tags within a changeset, at the same level as the Change Type:
Tag | Description |
---|---|
comment
|
Specifies the description of the changeset. XML comments provide the same benefit. |
preConditions
|
Preconditions required to execute the changelog. If global, must be passed before the changeset is run. Preconditions are typically used for doing a data sanity check before doing something unrecoverable such as a |
rollback
|
Specifies SQL statements or Change Type tags that describe how to rollback the changeset. For more information, see Liquibase Rollback Workflow and Automatic and Custom Rollbacks. |
validCheckSum
|
Adds a checksum that is considered valid for this changeset, regardless of what is stored in the database. It is
primarily used when you need to change a changeset and don't want errors thrown on databases on which it has already been run (not a recommended procedure). Special value "1:any" will match to any checksum and will not execute the changeset on ANY change. Since 1.7 |
<Any Refactoring Tag(s)> | Specifies the database change(s) to run as part of the changeset (Change Types). |
Some Change Types support additional nested tags, like column
, where
, and whereParams
. The scope of these tags is limited to the Change Type you place them in.