class ModifyStudy extends edu.northwestern.bioinformatics.bering.Migration {
    void up() {
 		if (databaseMatches('oracle')) {
     		execute('ALTER TABLE studies ADD completed integer NOT NULL')
     	} else if (databaseMatches('postgresql')) {
     		execute('ALTER TABLE studies ADD completed Boolean NOT NULL')     	
     	} else if (databaseMatches('hsqldb')) {
     		execute('ALTER TABLE studies ADD completed BOOLEAN NOT NULL')     	
     	}
     		
    }

    void down() {
 	  	execute('ALTER TABLE studies DROP COLUMN completed')
     }
}

class ModifyStudy extends edu.northwestern.bioinformatics.bering.Migration {
    void up() {
        if (databaseMatches('oracle')) {
            execute('ALTER TABLE studies ADD completed integer NOT NULL')
        } else {
            execute('ALTER TABLE studies ADD completed BOOLEAN NOT NULL')
        }
    }

    void down() {
        execute('ALTER TABLE studies DROP COLUMN completed')
    }
}

Use boolean column in the general case, instead of specifically for HSQLDB and PostgreSQL
Use boolean column in the general case, instead of specifically for HSQLDB and PostgreSQL
