DiscriminatorValue could be used in WHERE Statement in OneToMany Joins to Speed up the Result --------------------------------------------------------------------------------------------- Key: HHH-4477 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-4477 Project: Hibernate Core Issue Type: Improvement Affects Versions: 3.3.1 Reporter: Robert Bartl Currently the DiscriminatorValue is not used in Queries that fetch multiple Entities. Adding this could increase the Speed of the Fetch as another index could be used. Example: @Entity(name="Issues") public class Issue { @Id @Column(nullable = false, insertable = true, updatable = false) private int id; @OneToMany(cascade=CascadeType.ALL,fetch=FetchType.LAZY,mappedBy="objectId") private List<TicketTransaction> transactions; public List<TicketTransaction> getTransactions() { return transactions; } } @Entity(name = "Transactions") @Table(name = "Transactions") @Inheritance(strategy = InheritanceType.SINGLE_TABLE) @DiscriminatorColumn(name = "ObjectType", discriminatorType = DiscriminatorType.STRING, length = 20) @DiscriminatorValue("null") public abstract class Transaction { @Id @Column(nullable = false, insertable = true, updatable = false) private int id; } @DiscriminatorValue("Issue") @Entity public final class TicketTransaction extends Transaction { @Column(nullable = true, insertable = false, updatable = false, name = "ObjectId") private int objectId; } ObjectId is in ticketTransaction class because of HBX-1075 Bug, should have been in Transaction class. This setup results in the following Query if Issue.getTransactions() is called: select transactio0_.ObjectId as ObjectId1_, transactio0_.id as id1_, transactio0_.ObjectType as ObjectType4_0_, transactio0_.ObjectId as ObjectId4_0_ from Transactions transactio0_ where transactio0_.ObjectId=4236 missing: "AND ObjectType = 'Issue'" -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://opensource.atlassian.com/projects/hibernate/secure/Administrators.... - For more information on JIRA, see: http://www.atlassian.com/software/jira