Using Liquibase with PostgreSQL

PostgreSQL is an open-source, object-relational database system that supports a large part of the SQL standard and offers many modern features:

• complex queries
• foreign keys
• triggers
• updatable views
• transactional integrity
• multiversion concurrency control

For more information, see the PostgreSQL documentation page.

Verified versions

PostgreSQL, AWS RDS – PostgreSQL

• 15
• 14
• 13
• 12
• 11

AWS Aurora for PostgreSQL, Google Cloud SQL – PostgreSQL

• 14
• 13
• 12
• 11

Azure Database – Postresql – Flexible Server

• 13

Azure Database – Postresql – Single Server

• 11

Verification level

Note: A database's verification level indicates how well it works with different features in Liquibase and across different products, such as Liquibase Open Source and Liquibase Pro. For more information, see Database Verification Levels.

Advanced: Database has been tested and validated to deliver a minimum set of advanced capabilities around database inspection, support for long-running operations, as well as the Foundational level's basic functionality of change management and change tracking aligned with the database. The advanced database inspection capabilities include the ability to generate changelogs in at least one format and the support of at least two additional state-based commands (snapshots, diffs, etc). The Liquibase customer support team provides how-to/usage support around verified capabilities for commercial customers.

Prerequisites

1. Introduction to Liquibase – Dive into Liquibase concepts.
2. Install Liquibase – Download Liquibase on your machine.
3. Get Started with Liquibase – Learn how to use Liquibase with an example database.
4. Design Your Liquibase Project – Create a new Liquibase project folder and organize your changelogs
5. How to Apply Your Liquibase Pro License Key – If you use Liquibase Pro, activate your license.

Install drivers

To use Liquibase and PostgreSQL, you need the JDBC driver JAR file (Maven download).

The latest version of Liquibase has a pre-installed driver for this database in the liquibase/internal/lib directory, so you don't need to install it yourself. If you use Maven, you must instead include the driver JAR as a dependency in your pom.xml file.

<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>42.4.0</version>
</dependency>

Also, you can use the Liquibase PostgreSQL Extension JAR file, which is the vacuum extension that adds an additional changelog tag or command to support vacuuming.

Test your connection

1. Ensure PostgreSQL is configured:
• PostgreSQL
• PostgreSQL on AWS RDS
2. Specify the database URL in the liquibase.properties file (defaults file), along with other properties you want to set a default value for. Liquibase does not parse the URL. You can either specify the full database connection string or specify the URL using your database's standard JDBC format:
• PostgreSQL
• PostgreSQL on AWS RDS

3. Create a text file called changelog (.xml) in your project directory and add a changeset.

   If you already created a changelog using the init project command, you can use that instead of creating a new file. When adding onto an existing changelog, be sure to only add the changeset and to not duplicate the changelog header.

XML example

<?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:ext="http://www.liquibase.org/xml/ns/dbchangelog-ext"
    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-latest.xsd
        http://www.liquibase.org/xml/ns/dbchangelog-ext http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-ext.xsd
        http://www.liquibase.org/xml/ns/pro http://www.liquibase.org/xml/ns/pro/liquibase-pro-latest.xsd">

    <changeSet id="1" author="Liquibase">
        <createTable tableName="test_table">
            <column name="test_id" type="int">
                <constraints primaryKey="true"/>
            </column>
            <column name="test_column" type="varchar"/>
        </createTable>
    </changeSet>

</databaseChangeLog>

SQL example

-- liquibase formatted sql

-- changeset liquibase:1
CREATE TABLE test_table (test_id INT, test_column VARCHAR(255), PRIMARY KEY (test_id))

Tip: Formatted SQL changelogs generated from Liquibase versions before 4.2 might cause issues because of the lack of space after a double dash ( -- ). To fix this, add a space after the double dash. For example: -- liquibase formatted sql instead of --liquibase formatted sql and -- changeset myname:create-table instead of --changeset myname:create-table.

YAML example

databaseChangeLog:
   - changeSet:
       id: 1
       author: Liquibase
       changes:
       - createTable:
           tableName: test_table
           columns:
           - column:
               name: test_column
               type: INT
               constraints:
                   primaryKey:  true
                   nullable:  false

JSON example

{
  "databaseChangeLog": [
    {
      "changeSet": {
        "id": "1",
        "author": "Liquibase",
        "changes": [
          {
            "createTable": {
              "tableName": "test_table",
              "columns": [
                {
                  "column": {
                    "name": "test_column",
                    "type": "INT",
                    "constraints": {
                      "primaryKey": true,
                      "nullable": false
                    }
                  }
                }
              ]
            }
          }
        ]
      }
    }
  ]
}

4. Navigate to your project folder in the CLI and run the Liquibase status command to see whether the connection is successful:

liquibase status --username=test --password=test --changelog-file=<changelog.xml>

Note: You can specify arguments in the CLI or keep them in the Liquibase properties file.

If your connection is successful, you'll see a message like this:

4 changesets have not been applied to <your_jdbc_url>
Liquibase command 'status' was executed successfully.

5. Inspect the deployment SQL with the update-sql command:

liquibase update-sql --changelog-file=<changelog.xml>

6. Then make changes to your database with the update command:

liquibase update --changelog-file=<changelog.xml>

If your update is successful, Liquibase runs each changeset and displays a summary message ending with:

Liquibase: Update has been successful.
Liquibase command 'update' was executed successfully.

7. From a database UI tool, ensure that your database contains the test_table object you added along with the DATABASECHANGELOG table and DATABASECHANGELOGLOCK table.

Now you're ready to start making deployments with Liquibase!

PostgreSQL

• Check the status by running the pg_isready command. For more information about the options you can specify when running the command, see the pg_isready webpage.
• Specify the database URL in the Liquibase properties file, as follows:

url: jdbc:postgresql://<host>:<port>/<dbname>

Tip: To apply a Liquibase Pro key to your project, add the following property to the Liquibase properties file: licenseKey: <paste code here>

PostgreSQL on AWS RDS

Check the connection by using any standard SQL client application, including the psql command line utility that is part of a PostgreSQL installation, and running the following:

Linux, macOS, or Unix

psql \
--host=<DB instance endpoint> \
--port=<port> \
--username=<master username> \
--password \
--dbname=<database name>

Windows

psql ^
--host=<DB instance endpoint> ^
--port=<port> ^
--username=<master username> ^
--password ^
--dbname=<database name>

Note: If this is the first time you are connecting to your DB instance, you can try using the default database name postgres for the --dbname option.

Tip: The alternative way is to connect with pgAdmin, which is an open-source administration and development tool for PostgreSQL.

You can find the connection information in the AWS Management Console:

1. Sign in to the AWS Management Console and open the Amazon RDS console.
2. In the upper-right corner of the console, choose the AWS Region of your DB instance.
3. Find the host and port for your DB Instance:
   • Select Databases and choose the needed PostgreSQL DB instance to display the instance details.
   • Select Connectivity & security. You will see all information under Endpoint & Port.

Note: To find the connection information using the AWS CLI, call the describe-db-instances command: aws rds describe-db-instances. Alternatively, you can use the Amazon RDS API DescribeDBInstances operation.

Specify the database URL in the Liquibase properties file, as follows:

url: jdbc:postgresql://<instance_host>:<instance_port>/<database_name>?user=userName&password=password

Example: url: jdbc:postgresql://myinstance.123456789012.us-east-1.rds.amazonaws.com:5432/postgresql?user=user&password=password

Other

You can also use Liquibase on PostgreSQL with:

• AWS Aurora
• Azure Database – Flexible Server
• Azure Database – Single Server
• Google Cloud SQL

Related links

• PostgreSQL Documentation
• Getting Started: Using Liquibase with Azure Postgres
• Using Liquibase and AWS RDS
• Connecting to a DB instance running the PostgreSQL database engine
• Change Types
• Concepts
• Liquibase Commands
• Workflows
• Use PSQL and runWith on PostgreSQL