This document provides an introduction to database change management with Liquibase. It discusses why database change management is important, what Liquibase promises to deliver, including keeping changes portable, allowing rollbacks, and providing audit information. It also provides an overview of how to get started with Liquibase, including writing changesets in different formats, invoking the tool via the command line or build tools, and generating changesets from an existing database.

1. Database change management with
Liquibase
Introduction
Prepared by: Jarosław Szczepankiewicz
Submitted on: 2014-02-11
Version: 1.0
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2. Why should I care about db change management?
Can I quickly setup new instance on DEV / PROD?
What is the state of database on machine X in relation to
application version
Who did last upgrade of db? When?
How can I easily upgrade db to version X
How can i easily downgrade db to version Y
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3. Liquibase promises
Keep changes in special format as portable as possible
between DB versions
Let’s the tool check which changes should be applied to
upgrade the db to specified version
Allow me to rollback changes
Give audit information
Initialize the whole db from the ground
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4. How to start?
Write changes (changesets) in format you like:
XML (with XSD support), YAML, JSON, SQL
Invoke tool
Commandline
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Ant
Maven
Spring / CDI (as part of application lifecycle)

5. Let’s code!
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6. Rollbacks
Most DDL have rollbacks
Insert, drop X not autorollbacked
Can be declared empty (<rollback/>) but watch out!
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7. Parameters
From environment or declared in source
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8. Preconditions (for changesets)
Conditionally execute changeset
AND / OR / NOT available
Custom preconditions available (through interface
implementation)
Dbms, runningAs, changeSetExecuted, columnExists,
tableExists, viewExists, foreignKeyConstraintExists, indexExists,
sequenceExists
On changelog (applied to all files) or changeset level
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9. Custom SQL
Can specify „normal” instruction + rollback
Can be conditionally executed based on dbms type
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10. Not enough refactorings?
Create your own refactoring class and invoke from changeset
(liquibase.change.custom.CustomTaskChange,
liquibase.change.custom.CustomSqlRollback)
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11. Your project has already DB?
Generate changelog / sets from existing db
Not all features supported (triggers, procedures)
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DIFF
Check the difference between databases using content
analysing rather than changelog table history
Not recommended (limited abilities) but sometime usefull
Report mode (list) or changeset mode (*.xml)

13. DBDoc
Document state + history of changelog / db in javalike style
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14. Extensions
Hibernate – analyze db + mapping and generate diff
MS SQL / Oracle / Postgresql extensions
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…

15. Thank you
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