Introduction

In the spirit of TDD this library is intended to help facilitate schema migrations where table creation scripts, and alter commands are stored in XML and then applied to a database.

Overview

The mechanics are simple:

Step 1

Read database scripts from XML. The script with table creation and alter commands looks like this:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<databases>
    <database>
        <version>1</version>
        <script><![CDATA[
create table user_details (id int);
    ]]></script>
    </database>
    <database>
        <version>2</version>
        <script><![CDATA[
create table something_else (id int);
    ]]></script>
    </database>
</databases>

Step 2

The library will query the DB to determine the DB's current version via a version history table. After that it applies the list of scripts found in the above file to the DB which cause it to arrive at a 'target version'.

The code using the library to migrate the DB:

    Databases dbs = new XmlIO().read("sql/db-versions.xml", Databases.class);

    DbVersioning v = new DbVersioning(
        new DBI(applicationConnection()),
        new VersionScriptProvider(),
        new TransitionChecks(),
        MIGRATIONS_USER
    );

    v.toTargetVersion(dbs.getDatabases(), 2);

Step 3

Write tests that guarantee the updates applied via the 2 scripts, and the behavior which the DB helps to facilitate for a given application.

Setup

Currently, the project isn't held in a MVN repo (hopefully I'll update that soon). So, it must be installed manually and then a POM dependency can be used by any code base. To install it manually follow these steps:

• Install Dependencies: Java 8 and Maven.
• Clone this repo somewhere: %> git clone [this-repo]
• Run mvn package %> mvn package
• Run mvn install %> mvn install
• Use this Maven dependency in a project:

<dependency>
  <groupId>XplorJavaDB</groupId>
  <artifactId>XplorJavaDB</artifactId>
  <version>1.0-SNAPSHOT</version>
</dependency>

After that you should be able to run the code found in Step 2 above.