Product articles Flyway Database migrations

Try Before You Commit in Flyway

Sometimes we want to check whether it is possible to run a Flyway migration without error, but not actually make the changes. We might just need to 'sanity test' the performance of a migration on the Staging server, for example. By using a placeholder 'switch' to trigger a SQL Exception, we can get Flyway to roll-back its transaction, and therefore the migration, on demand. Read more

Finding the Version of a Flyway-managed Database Using SQL

Maintaining a version of a database opens a lot of possibilities, especially if an automated process can easily grab the current version, at runtime, using just SQL. You might, for example, have a routine that is only appropriate after a particular version. It is also very handy to be able to associate entries in an event log or bug report with the database version. No more desultory quests, when dealing with support issues, or when bug fixing, to find which database version was running when the bug happened. Read more

Rollbacks, Undos and Undonts

Rollback scripts are designed to allow us to recover safely from a failed deployment that leaves the database in an indeterminate state. They must check exactly what needs to be reverted before doing so. If you work with an RDBMS that cannot support transaction DDL rollback they are vital. This article proposes a strategy where you create and test a rollback file, at the same time as the forward migration, and reuse it as a Flyway undo script. Read more

Managing Datasets for Database Development Work using Flyway

A generic way of exporting, deleting and loading data, for database development work. It uses Flyway Teams, a PowerShell framework, JSON files for storage and a table manifest to define the correct order of dependency for each task. It should help a team maintain datasets between database versions, as well as to switch between the datasets required to support different types of testing. Read more

Re-baselining a Database using Flyway Desktop

Over time, Flyway projects can accumulate a lot of migration scripts, with many database objects being created, altered, and dropped across many files. Tonie Huizer explains why you might want to create a new baseline migration file to create the latest version of a  Flyway-managed database in a single leap, and how to persuade Flyway Desktop to do it. Read more

Building a Database with Flyway

Flyway, especially Flyway Teams edition, can be used in several different ways to accommodate a database development that was originally based on builds rather than migrations. This article explores four different ways to use Flyway to build a particular version of a database, from the ground up, using a single migration script. It should help teams select the best way to incorporate Flyway into an existing database build system, during development, while benefitting from use of Flyway's versioned migration system for deployments and releases. Read more

Taming Database Documentation with Flyway and MySQL

Database object documentation is essential for explaining to busy developers, and the wider business, the purpose of each object and how to use it. The solution presented in this article consists of a SQL script to allow developers to add comments to MySQL database objects, without affecting the database version, and a simple way to generate a documentation report, in JSON. The SQL script will execute automatically as a callback, during any Flyway Teams migration run, and the report will allow the team to spot any gaps quickly. Read more

Getting Started with Flyway and any RDBMS

How to get started with Flyway, as simply as possible, using PowerShell. This article provides a practice set of Flyway migration scripts that will build the original pubs database on either SQL Server, PostgreSQL, MySQL, MariaDB or SQLite and then migrate it from version to version, making a series of improvements to its schema design. Read more

Flyway How-tos: a User’s Perspective

Flyway provides a database-independent way for a team to track, manage and apply database changes, while maintaining strict control of database versions. It updates a database by running a series of versioned migration scripts, in order, and keeps track of all the changes in a special "schema history" table. It sounds simple, but it is easy to derail this team discipline if you don't find the right answers to the following questions… Read more

What is the Flyway Teamwork Framework?

The FlywayTeamwork PowerShell framework is designed to help get you started quickly with scripting Flyway migrations for a range of database systems. It introduces a PowerShell task library to help with the scripting of repetitive chores and to generate some of the 'build artifacts' that are often required during team development work. This article explains the basics of the framework's design and provides a demo how to use Flyway to migrate a PostgreSQL database, while generating a high-level narrative of the changes made between versions. Read more

Flyway Gotchas

Explaining some of the 'gotchas' that can trip up the unwary Flyway user, and how to avoid them. One or two of these you'll encounter quickly, such as the case-sensitivity of parameters and arguments. Others, such as potential problems with undo scripts or running scripted callbacks, only when you are tackling more complex development processes. Read more

Testing a Flyway Database Migration

Often, we want to test the new version of a database, produced by a Flyway migration, before committing the new migration file, or to test the same migration run on a number of different databases. This article demonstrates how to do it, by generating and using JSON parameter files to run a series of Flyway actions on any number of databases, on any number of servers. Read more

Exploring the Flyway Schema History Table

Flyway uses a schema history table to track the version of each database, recording in it every versioned migration file applied to build that version. It's worth understanding exactly how Flyway uses this table, the possible dangers of moving it to a non-default location and how to do it safely, if required. Read more

Flyway Teams and the Problem of Database Variants

The 'ShouldExecute' script configuration option in Flyway Teams simplifies 'conditional execution' of SQL migration files. This makes it easier to support multiple application versions from the same Flyway project, to deal with different cultural or legislative requirements. It also helps developers handle environmental differences between development, test and staging, such as the need to support multiple versions or releases of the RDBMS. Read more

Flyway Without the Typing

How to use Flyway configuration files to minimize typing during ad-hoc development from PowerShell or DOS; you just type in the Flyway commands you need and hit "go" and the config files take care of all the tiresome connection, authentication and project details. Read more