[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-5114) Column 'timestamp' in field list is ambiguous

Column 'timestamp' in field list is ambiguous --------------------------------------------- Key: HHH-5114 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-5114 Project: Hibernate Core Issue Type: Bug Affects Versions: 3.5.0-Final Environment: MySQL 5.1.45, MySQL5InnoDBDialect Reporter: ChB I ran into the following error today: 'Column 'timestamp' in field list is ambiguous' So i tried to figure out what is causing this. I have the following mapping ( public class X @OneToOne(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "y") @org.hibernate.annotations.Fetch(FetchMode.JOIN) public Y getY() { return this.y; } } public class Y @OneToOne(fetch = FetchType.EAGER) @JoinColumn(name = "x_id", unique = true, nullable = false, insertable = false, updatable = false) public X getX() { return this.x; } } and had the following Query "select x from X as y ..." which resulted in select bla0_.x_id as x_id1_5_4_, bla0_.xyz as xyz2_5_4_, timestamp as timestamp5_4_, foo1_.id as id3_0_, ... bla4_.x_id as x_id1_5_3_, bla4_.xyz as xyz2_5_3_, timestamp as timestamp5_3_ from Y bla0_ left outer join X foo1_ on bla0_.x_id=foo1_.id ... left outer join Y bla4_ on foo1_.id=bla4_.x_id As you can obviously see this is a combination of 2 bugs: 1.) The text 'bla0_.' is missing prior to 'timestamp' (first occurence) and 'bla4_.' is missing prior to 'timestamp' (next occurence) 2.) For no reason the table Y is loaded twice from the DB (as bla0_ and bla4_) This might be dialect specific, I'm using MySQL5InnoDBDialect. I could work around this by removing "(a)org.hibernate.annotations.Fetch(FetchMode.JOIN)", but thats not a real solution. This did not happend with hibernate 3.3.