Migrate4j - Database Migration Tool for Java

Migrate4j is a migration tool for java, similar to Ruby's db:migrate task. Unlike other Java based migration tools, database schema changes are defined in Java, not SQL. This means your migrations can be applied to different database engines without worrying about whether your DDL statements will still work.

Schema changes are defined in Migration classes, which define "up" and "down" methods - "up" is called when a Migration is being applied, while "down" is called when it is being rolled back. A simple Migration, which simply adds a table to a database, is written as:

package db.migrations;
import static com.eroi.migrate.Define.*;
import static com.eroi.migrate.Define.DataTypes.*;
import static com.eroi.migrate.Execute.*;
import com.eroi.migrate.Migration;
public class Migration_1 implements Migration 
{
 public void up() 
 {
    createTable(
      table("simple_table", 
              column("id", INTEGER, primaryKey(), notnull()),
           column("desc", VARCHAR, length(50), defaultValue("NA"))));
   }

  
  public void down() 
 {
    dropTable("simple_table");
  }
} 

This Migration can be applied at application startup, from an Ant task (included in migrate4j) or from the command line. Migrate4j will only apply the migration if it has not yet been applied. LIkewise, migrate4j will roll back the migration when instructed, only if the migration has been previously applied.

The migrate4j team is happy to announce a new release which adds improved usability (simplified syntax), additional schema changes and support for more database products. While migrate4j does not yet have support for all database products, we are actively seeking developers interested in helping fix this situation.

Visit http://migrate4j.sourceforge.net for more information on how migrate4j can simplify synchronizing your databases. To obtain migrate4j, go to http://sourceforge.net/projects/migrate4j and download the latest release. For questions or to help with future development of migrate4j, email us at migrate4j-users AT lists.sourceforge.net (replacing the AT with the "at symbol").