Flyway - Database Migrations Made Easy

We all take version control for granted. And it is, when it comes to code. On the database side, however schema evolution is often performed ad-hoc: a quick statement here, a little script there. The result: confusion and uncertainty. Has this update already been applied on this instance? Should we apply this other script first? Is our application going to run against this database?

No more! This is where database migration tools come to the rescue! We'll look at a popular open-source choice called Flyway. By the end of the session, you'll have a solid understanding of what it does, how it works and how to effectively integrate it into your project. We'll look at concepts and solutions. We'll tackle the hard problems and show you how this fits in a Continuous Delivery and Zero Downtime workflow. This will transform how you deal with your database, and you'll never look back.

Transcript

1. AXEL FONTAINE
   @axelfontaine
   axel@boxfuse.com
   Database Migrations made Easy
   

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2. About Axel Fontaine
   • Founder and CEO of Boxfuse
   • Over 15 years industry experience
   • Continuous Delivery expert & trainer
   • Regular speaker at tech conferences
   • JavaOne RockStar in 2014
   @axelfontaine
   

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3. flywaydb.org
   

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4. boxfuse.com
   

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5. about
   questions
   

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6. Who is using a relational database ?
   

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8. Why should you use a relational database ?
   • ACID
   • Battle-tested reliability
   • Performance
   • Scaling up
   • Slice & dice data
   • Defer decisions
   

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9. relational databases
   should be the default choice
   for new projects
   

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10. What about scaling ???
    

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11. Algorithms are for
    people who don’t know
    how to buy RAM.
    Clay Shirky
    

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12. RAM is the new disk
    

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13. The secrets of scaling
    • Buy RAM (it’s cheap!)
    • Keep LOBs out of the DB
    (only store a reference)
    • Only then look at techniques like sharding
    

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14. Here is a small story
    

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16. What about NoSQL ???
    

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17. NoSQL databases are like divas
    They can be great,
    but you’d better know how to please them
    

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18. Now let’s talk about database migrations ...
    

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20. POLL:
    how are you doing database migrations?
    • Ad-hoc individual statements
    • Scripts (ad-hoc)
    • In-house tool (automated)
    • DB Migration tool
    • DB Migration API on App startup
    

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21. APP
    

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23. APP
    

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24. APP
    Axel
    APP
    Prod
    APP
    Test
    APP
    CI
    APP
    Christian
    

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25. SQL
    

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26. SQL
    SQL
    SQL
    ?
    ?
    ?
    

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27. flywaydb.org
    

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28. 5
    years old
    

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29. 250 000+
    downloads in 2014
    

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32. With techniques such as continuous delivery becoming
    more mainstream, automated database migrations are a
    baseline capability for many software teams. While there
    are many tools in this space, we continue to
    recommend Flyway for its low-friction approach. Flyway
    has a vibrant open-source community behind it, and
    support for both traditional and cloud-based databases
    such as Amazon Redshift and Google Cloud SQL.
    -- ThoughtWorks
    

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33. How does Flyway work ???
    

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34. SQL
    SQL
    SQL
    ?
    ?
    ?
    

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35. How does Flyway work ???
    Empty DB
    

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36. How does Flyway work ???
    Empty DB Version 2
    Version 1
    

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37. What were Flyway’s design goals ???
    

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38. It just works
    

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39. Keeping it simple
    (saying no)
    

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40. Convention
    over
    Configuration
    

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41. No
    Lock-in
    

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42. 0
    required dependencies
    

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43. 6
    commands
    info clean
    migrate baseline
    validate repair
    

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44. Demo
    

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45. Supported databases
    

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46. Supported execution platforms
    

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47. Third party plugins
    

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48. Basic architecture
    Migration
    Resolver
    API
    Database-
    specific
    support
    Metadata
    Table
    Migration
    Executor
    

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49. Flyway flyway = new Flyway();
    flyway.setDataSource(url, user, password);
    flyway.migrate();
    

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50. mvn flyway:migrate
    
    …
    …
    …
    
    

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51. 
    

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52. flyway migrate -url=… -user=… -password=…
    

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53. gradle flywayMigrate
    flyway {
    url = ‘…’
    user = ‘…’
    password = ‘…’
    }
    

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54. Demo
    

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55. When should you migrate the database ???
    

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56. Code and database share the same lifecycle
    So why risk having them not fit together?
    

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57. Database migration should be
    performed on application startup
    

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58. Flyway flyway = new Flyway();
    flyway.setDataSource(url, user, password);
    flyway.migrate();
    

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59. The Fear
    of
    DDL
    

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60. VS
    DML DDL
    

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61. Name Balance
    Homer 163
    Marge 214
    Bart 9
    Lisa 25
    

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62. VS
    DML DDL
    Name Balance
    Homer 0
    Marge 0
    Bart 0
    Lisa 0
    Name
    Homer
    Marge
    Bart
    Lisa
    From a business perspective
    the risk of DML and DDL is the same
    

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63. Demo
    

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64. A word about in-memory databases
    

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65. Do you really want to test your code
    with a different query engine
    from the one you have in production???
    

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66. Getting started
    

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67. http://flywaydb.org/getstarted
    

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68. Summary
    • Use a database migration tool
    

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69. Summary
    • Use a database migration tool
    • Run it on application startup
    • Get started tomorrow 
    

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70. flywaydb.org
    

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71. Thanks !
    AXEL FONTAINE
    @axelfontaine
    flywaydb.org boxfuse.com
    

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