JPA 使用annotation設定self join結構的Entity bean

請參考：
http://detailfocused.blogspot.com/2009/05/jpa-self-join-table.html

JPA/hibernate 使用MySQL讓資料為UTF-8 encoding

使用JPA/hibernate時若要讓預設資料庫的encoding為utf-8,並預設engine為innodb,則設定my.cnf在[mysqld]區段加上：
default-character-set=utf8
default-collation=utf8_general_ci
default-storage-engine=innodb
另外,Datasource JDBC url要加上
?characterEncoding=UTF-8&useUnicode=true&connectionCollation=utf8_general_ci&characterSetResults=utf8