www.linkedin.com/in/bjornongenae

@BjornOngenae

Bjorn Ongenae

Development: The code side

Development: The database side (1/2)

Development: The database side (2/2)

DEV

PRODHmm, what to release this week?

New tables, some data, a view or two,…

Let’s compare

Version well defined Say what?

Version controlled sources On a good day locally

Well defined release I’ll have a look

The code The database

Let’s focus on the database for once

Version well defined Say what?

Version controlled sources On a good day locally

Well defined release I’ll have a look

The code The database

Ever considered database migrations?

Recreate from scratch

Clear state

Easy version upgrades

+

+=

How does it work

Step 1: version control

Creates a table SCHEMA_VERSION schema_version

How does it work

Step 1: version control

Creates a table SCHEMA_VERSION

Step 2: scanning

Scan filesystem/classpath for new migrations

schema_version

version 1

How does it work

Step 1: version control

Creates a table SCHEMA_VERSION

Step 2: scanning

Scan filesystem/classpath for new migrations

Step 3: sorting

Sort the new migrations on version number

schema_version

version 2

Inside the schema_version table

Ready to migrate

Step 1: version control

Creates a table SCHEMA_VERSION

Step 2: scanning

Scan filesystem/classpath for new migrations

Step 3: sorting

Sort the new migrations on version number

schema_version

version 2.8.1

pending

Result after migration

How do migrations look like? (1/3)

Plain SQL

Versioned

Repeatable

Java

V2.1__create_bar_invite.sql

CREATE TABLE bar_invite ( id uuid NOT NULL, email text NOT NULL, registration uuid, created_on timestamp with time zone NOT NULL, bar_id uuid, user_id uuid, bartender boolean);

How do migrations look like? (2/3)

Plain SQL

Versioned

Repeatable

Java

R__create_bar_invite_view.sql

CREATE OR REPLACE VIEW bar_invite_emails AS select email from bar_invites;

How do migrations look like? (3/3)

Plain SQL

Versioned

Repeatable

Java

V1_2__Another_user

Where to store the migrations?

Yeah nice, but how to run the migrations?

Maven API Command line

GradleAnt Scala Build Tool

Let’s migrate using Maven (1/2)

Step 1: add dependency

Obtains the Flyway library

Step 2: configure

Configure database, user, password,…

Step 3: run

mvn flyway:migrate

Let’s migrate using Maven (2/2)

Any other commands?

Migrate Clean Info

RepairValidate Baseline