This document discusses database source control and automation. It introduces Flyway, an open source tool for database migrations. Flyway uses SQL scripts to represent database changes and tracks their execution in a metadata table. It scans script directories and applies migrations in order of their version numbers. The document demonstrates Flyway and discusses challenges like managing branches, script expiration, dependencies, and developer sandboxes when using a version control system for database scripts and Flyway.

1. Road To Database Automation
Database Source Control
Eduardo Piairo

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5. Database Source Control
Eduardo Piairo
DBA & DevOps
About me
@EdPiairo
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eduardopiairo@outlook.com
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6. Database Source Control
Overview
Source
Control
Continuous
Integration
Continuous
Delivery
Database
+
Application

7. Database Source Control
What’s so special about databases?
Overview

8. Database Source Control
Motivation
Database are out of pace with application development
Need of synchronization between development and DBA teams
No traceability of database changes (changes history)
What changed? Why? When? Who?
Manual databases processes prevent the CI and CD utilization in their full extent
Database release process is manual
Time consuming and error prone
Releases are less frequent and risky

9. Database Source Control
Motivation
Tests are manual or do not exists
Bugs in production environment
Database related bugs are only discovered after deployment to production
Fixes and hotfixes have time cost, what can lead to delay a release
Inability to roll back to the previous version of a database
Database setup time of a new environment
Databases become a bottleneck in agile delivery processes

10. Database Source Control
Why database automation?
Enable control over database development
Keep a versioned “history” of database sates
Increase release frequency though repeatability of processes
Greater predictability over releases
Efficiency by eliminating the repetition of a range of manual activities
Reduce time spent fixing bugs
More control, less exposure to error

11. Database Source Control
Why database automation?
Faster speed of response to change
Automated deployment of smaller units of change
Remove/reduce human intervention in the release process
The build step is automatic triggered by a “push” into source control repository
The deploy step is automatic triggered by a successfully build process
Greater reliability of the release process
Providing a series of automated test stages prior to deployment
Maintain an agile development environment

12. Database Source Control
Why database source control?
First step for database automation
Share code (SQL scripts)
Keep history of each change
Your best comunication system
Enforce standards

13. Database Source Control
Migrations-based approach vs State-based approach
Fundamental resource: SQL Script

14. Database Source Control
Migrations-based approach vs State-based approach
State based solutions
Script represents the current database state
Your source of truth is how the database should be
Migrations based solutions
Script represents a migration
Migration represents how to transition to the next database version
Your source of truth is how the database should change

15. Database Source Control
Flyway
Flyway – “Database migrations made easy”
http://flywaydb.org/
Open source database migration tool
Flyway command-line
Simplicity: easy to setup, no need to install
Zero dependencies (java + jdbc)
Scripts are written in SQL

16. Database Source Control
Demo

17. Database Source Control
Flyway – How it works?
Flyway commands
migrate, clean info, validate, baseline repair
Metadata table
Used to track the state of the database
If the database is empty, flyway won’t find it and will create it
Flyway scans the migrations directory and check migrations against the metadata table
Migrations are sorted based on their version number and applied in order

18. Database Source Control
Version Control System – The system
Two components:
Database scripts repository
Flyway – database migrations
Example:
V20161001.1100__Create_TB_MyTable.sql
Rule 1: Script version (timestamp)
Rule 2: Operation type
Rule 3: Object type
Rule 4: Object name

19. Database Source Control
Demo

20. Database Source Control
Version Control System – Challenges
Challenge 1 – manage multiple branches
In other words, is necessary to mange merge/interests conflicts
The default branch is the main/master branch and all the merges for this branch must be
done with caution
Challenge 2 – script expiration date
Should the migration script have expiration date?
Sometimes, in the next day the migration script makes no sense anymore

21. Database Source Control
Version Control System – Challenges
Challenge 3 – migration scripts stack
How can I manage the dependencies between different databases?
And how about dependencies between applications/components
Challenge 4 – developer sandbox
How to supply a disposable development environment where the database is
included?

22. Database Source Control
What’s next?

23. Database Source Control
Q&A
@EdPiairo
https://pt.linkedin.com/in/jesuspiairo
eduardopiairo@outlook.com
http://www.eduardopiairo.com/