Lets be honest - managing database changes can sometimes feel like juggling fire. Youve got multiple developers making updates, environments to manage, rollbacks to worry about, and lets not forget those late-night It worked on dev! surprises. It worked on dev! But guess what? There's a tool that can help you stay ahead of the chaos. Its called Liquibase, and it's like having a helpful assistant who always remembers what changes were made, who made them, and when. Today, we're going to break it down - what Liquibase is, how it works (especially with YAML), why it's useful, and how it's being used in real projects like mux-sql. But guess what? But guess what? Liquibase mux-sql So grab your favourite cup of coffee , and lets dive in! What is Liquibase? Liquibase is an open-source database change management tool. Think of it as version control, but for your database. Just like Git helps developers manage changes in their code, Liquibase helps you manage changes in your database schema. It keeps track of all the changes you've made (like adding tables, modifying columns, or creating indexes) and applies them in a controlled, consistent way across different environments - dev, test, staging, production. And yes, it works with most major databases: MySQL, PostgreSQL, Oracle, SQL Server, and many others. Why Should You Care? You might be thinking, My team already handles DB scripts manually. Why switch? Heres why Liquibase can make your life easier: No More Manual Scripts: Say goodbye to writing and tracking V1__create_table.sql, V2__add_column.sql, and so on.Tracks Whats Been Applied: It keeps a changelog and logs every change in a special table (DATABASECHANGELOG) inside your DB.Works with CI/CD: Automate your DB updates during deployments.Supports Rollbacks: Made a mistake? You can roll back changes with a command.Clear Audit Trail: Know who changed what and when. No More Manual Scripts: Say goodbye to writing and tracking V1__create_table.sql, V2__add_column.sql, and so on. No More Manual Scripts V1__create_table.sql V2__add_column.sql Tracks Whats Been Applied: It keeps a changelog and logs every change in a special table (DATABASECHANGELOG) inside your DB. Tracks Whats Been Applied DATABASECHANGELOG Works with CI/CD: Automate your DB updates during deployments. Works with CI/CD Supports Rollbacks: Made a mistake? You can roll back changes with a command. Supports Rollbacks Clear Audit Trail: Know who changed what and when. Clear Audit Trail In short, Liquibase gives you control, clarity, and confidence when managing DB updates. How Does It Work? Liquibase works using something called a changelog. This is a file where you define all your database changes using a format like YAML, XML, JSON, or SQL. Each change is grouped into a changeseta small, trackable unit of change. changelog changeset Here's an example from the mux-sql app's Liquibase YAML file: mux-sql app's Liquibase YAML file databaseChangeLog:
  - includeAll:
      path: sql
      relativeToChangelogFile: true

  - changeSet:
      id: product-table
      author: claude
      labels: products-api
      comment: Creating product table for REST API
      changes:
        - createTable:
            tableName: products
            columns:
              - column:
                  name: id
                  type: SERIAL
                  constraints:
                    primaryKey: true
              - column:
                  name: name
                  type: VARCHAR(100)
                  constraints:
                    nullable: false
              - column:
                  name: price
                  type: NUMERIC(10,2)
                  defaultValue: 0.00
                  constraints:
                    nullable: false databaseChangeLog:
  - includeAll:
      path: sql
      relativeToChangelogFile: true

  - changeSet:
      id: product-table
      author: claude
      labels: products-api
      comment: Creating product table for REST API
      changes:
        - createTable:
            tableName: products
            columns:
              - column:
                  name: id
                  type: SERIAL
                  constraints:
                    primaryKey: true
              - column:
                  name: name
                  type: VARCHAR(100)
                  constraints:
                    nullable: false
              - column:
                  name: price
                  type: NUMERIC(10,2)
                  defaultValue: 0.00
                  constraints:
                    nullable: false This snippet says: Hey, create a table called users with id, username, and email columns. The id is the primary key and cannot be null. users id username email id Once you run Liquibase, it reads this changelog, checks which changes havent been applied yet (based on the DATABASECHANGELOG table), and runs the SQL under the hood to make the changes. Easy, right? DATABASECHANGELOG Easy, right? Easy, right? YAML + Liquibase: A Perfect Match made in heaven Many DBAs are familiar with SQL, but YAML might feel new. Dont worry - YAML is just a human-readable way to structure data. Its like writing your changes in plain English. Why use YAML? Its clean and readable.Great for code reviews.Less error-prone than long SQL scripts.Supported natively by Liquibase. Its clean and readable. clean and readable Great for code reviews. code reviews Less error-prone than long SQL scripts. Less error-prone Supported natively by Liquibase. If youve ever worked with configuration files in Kubernetes, Docker Compose, or CI tools like GitHub Actions - youve already used YAML. Youre ahead of the game! A Real-World Example: Mux + PostgreSQL Lets talk about something real. The mux-sql project uses Liquibase with a YAML changelog to manage its database schema. It's a backend app built with Go, and like many projects, it needs to manage a growing database as new features are added. mux-sql Heres how theyve set things up: They use a liquibase.yml file in the root of their project.All database changes (like new tables, updates) are defined inside it.Developers make schema changes by adding new changesets.When the app is deployed, Liquibase applies only the new changes.The team doesnt have to guess what version the database is onLiquibase handles it. They use a liquibase.yml file in the root of their project. liquibase.yml All database changes (like new tables, updates) are defined inside it. Developers make schema changes by adding new changesets. changesets When the app is deployed, Liquibase applies only the new changes. The team doesnt have to guess what version the database is onLiquibase handles it. This approach keeps things clean, consistent, and avoids the Did we run that script on staging? drama. Did we run that script on staging? Did we run that script on staging? Liquibase OSS in CI/CD = New Power Duo Now, let's level up, if your team is using a CI/CD pipeline (like Harness, or Jenkins), you can run Liquibase automatically whenever you deploy. Imagine this: A developer creates a new table.They add a new changeset to the YAML changelog.They push their code.Your CI pipeline runs, and Liquibase applies the new schema changes as part of the deploy. A developer creates a new table. They add a new changeset to the YAML changelog. changeset They push their code. Your CI pipeline runs, and Liquibase applies the new schema changes as part of the deploy. Boom! Database updated, and everyones happy. No more hunting down SQL scripts or forgetting to run migrations. Harness Database DevOps: Leveling Up Liquibase in CI/CD Harness Database DevOps: Leveling Up Liquibase in CI/CD While Liquibase takes care of schema versioning and migrations, Harness Database DevOps integrates it seamlessly into your CI/CD pipelines. Think of it as Liquibase + automation + governance. With Harness, you can: Automate database deployments alongside app deployments.Manage approvals, policies, and environment rollouts.Use built-in failure strategies (like rollback on error or ignore) to safeguard production.Get visibility into who deployed what, and when. Automate database deployments alongside app deployments. Manage approvals, policies, and environment rollouts. Use built-in failure strategies (like rollback on error or ignore) to safeguard production. Get visibility into who deployed what, and when. In short, Liquibase gives you the migrations, Harness makes them safe, automated, and production-ready. But what About Rollbacks? Mistakes happen. Maybe a changeset dropped the wrong column. Dont worryLiquibase has rollback support. You can define a rollback inside your changeset like this: changeset databaseChangeLog:  
- includeAll:      
    path: sql      
    relativeToChangelogFile: true  
- changeSet:      
    id: product
    author: sonichigo
    labels: products-api
    comment: Creating product table for REST API      
    changes:        
      - createTable:            
            tableName: products            
            columns:              
              - column:                  
                  name: id                  
                  type: SERIAL                  
                  constraints:                    
                  primaryKey: true              
              - column:                 
                  name: name                  
                  type: VARCHAR(100)                  
                  constraints:                    
                  nullable: false              
              - column:                 
                  name: price                  
                  type: NUMERIC(10,2)                  
                  constraints:                    
                  nullable: false                  
                  defaultValue: 0.00      
                  rollback:       
      - dropTable:            
            tableName: products databaseChangeLog:  
- includeAll:      
    path: sql      
    relativeToChangelogFile: true  
- changeSet:      
    id: product
    author: sonichigo
    labels: products-api
    comment: Creating product table for REST API      
    changes:        
      - createTable:            
            tableName: products            
            columns:              
              - column:                  
                  name: id                  
                  type: SERIAL                  
                  constraints:                    
                  primaryKey: true              
              - column:                 
                  name: name                  
                  type: VARCHAR(100)                  
                  constraints:                    
                  nullable: false              
              - column:                 
                  name: price                  
                  type: NUMERIC(10,2)                  
                  constraints:                    
                  nullable: false                  
                  defaultValue: 0.00      
                  rollback:       
      - dropTable:            
            tableName: products Now, if something goes wrong, you can just run: liquibase rollbackCount 1 liquibase rollbackCount 1 And it will undo that change. Peace of mind, built-in. Best Practices for DB Admins Using Liquibase Here are a few tips to make the most of Liquibase: Use descriptive id and author in each changeset helps trace who did what.Keep changelogs in version control (Git) treat schema as code.Test locally before pushing changes always!Use Liquibase commands to validate before applying changes: liquibase validateModularize your changelogs if your project gets big. You can include files. Use descriptive id and author in each changeset helps trace who did what. Use descriptive id author Keep changelogs in version control (Git) treat schema as code. Keep changelogs in version control (Git) Test locally before pushing changes always! Test locally before pushing changes Use Liquibase commands to validate before applying changes: liquibase validate Use Liquibase commands to validate liquibase validate Modularize your changelogs if your project gets big. You can include files. Modularize your changelogs include The Learning Curve? Not So Steep! Some folks might worry that using Liquibase adds complexity. But in practice, it actually reduces complexity. No more guesswork. No more broken SQL files. No more It worked on my machine. reduces Instead, you get: A single source of truth.Audit history of every change.Easy rollbacks and repeatable deploys. A single source of truth. Audit history of every change. Easy rollbacks and repeatable deploys. Once you use it on a few projects, it becomes second nature. Conclusion Liquibase is like the superhero sidekick you didnt know you needed. It helps you: Track database changes.Apply them in a consistent way.Roll them back when things go sideways.Work better with your team and CI/CD pipelines. Track database changes. Apply them in a consistent way. Roll them back when things go sideways. Work better with your team and CI/CD pipelines. If you're a DB Admin tired of manual SQL chaos, it's worth giving Liquibase a try. The mux-sql project shows just how clean and simple a YAML-based changelog can be. If Liquibase is the superhero sidekick for DB admins, Harness Database DevOps is the command center. It extends Liquibase’s strengths, schema tracking, YAML changelogs, rollbacks, into a fully automated, policy-driven pipeline. The result? Faster releases, fewer errors, and total confidence in your database deployments. mux-sql project FAQs 1. Do I need to know Java to use Liquibase? Do I need to know Java to use Liquibase? Nope! Liquibase is built in Java, but you dont need to write any Java code to use it. You just need the Java Runtime Environment (JRE) installed to run the Liquibase CLI. Everything else like - YAML, SQL, or XML changelogs is what you already know. Nope! 2. Can I use Liquibase with my existing database? Can I use Liquibase with my existing database? Yes. Liquibase can integrate with an existing database by using the generateChangeLog command to capture the current state. From there, you can start tracking future changes incrementally with changesets. Yes. generateChangeLog 3. What if I accidentally apply the wrong changeset? What if I accidentally apply the wrong changeset? Thats where rollback comes in. If youve defined a rollback block inside the changeset, you can undo changes safely using a simple command like: rollback liquibase rollbackCount 1 liquibase rollbackCount 1 Without a defined rollback, youll need to handle it manuallybut Liquibase will still show you what was applied and when. 4. Can multiple developers work on the same changelog? Can multiple developers work on the same changelog? Yes, but with structure. Each developer should add their own changesets with unique ids and authors. Keeping changelogs in version control (like Git) and modularizing them with include files helps avoid merge conflicts. Yes, but with structure. id include Further Resources 📘Introducing Harness Database DevOps🤔Automating Environment-Specific Verification Queries with Liquibase💻 mux-sql Liquibase Example 📘Introducing Harness Database DevOps Introducing Harness Database DevOps Introducing Harness Database DevOps 🤔Automating Environment-Specific Verification Queries with Liquibase Automating Environment-Specific Verification Queries with Liquibase Automating Environment-Specific Verification Queries with Liquibase 💻 mux-sql Liquibase Example mux-sql Liquibase Example mux-sql Liquibase Example

How Database DevOps Makes Life Easy for DB Admins

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