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Is anyone aware of the validity of Hibernate's Criteria.list() and Query.list() methods returning multiple occurrences of the same entity?
Occasionally I find when using the Criteria API, that changing the default fetch strategy in my class mapping definition (from "select" to "join") can sometimes affect how many references to the same entity can appear in the resulting output of list(), and I'm unsure whether to treat this as a bug or not. The javadoc does not define it, it simply says "The list of matched query results." (thanks guys).
If this is expected and normal behaviour, then I can de-dup the list myself, that's not a problem, but if it's a bug, then I would prefer to avoid it, rather than de-dup the results and try to ignore it.
Anyone got any experience of this?
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Issue with @Id column, If we check closely, @Id column value is same for all the rows. Hence hibernate/JPA not able to get different records, it just get 1st record with this @Id and return duplicate records of it. Solution - Use @IdClass with columns which result in unique row instead of duplicate row.
Criteria crit = session. createCriteria(Test. class); final ResultTransformer trans = new DistinctRootEntityResultTransformer(); crit. setResultTransformer(trans); List rsList = trans.
The easiest way is to designate the primary key as UNIQUE. Be sure to check the return value of your insert commands as then the server will reject the duplicates.
Yes, getting duplicates is perfectly possible if you construct your queries so that this can happen. See for example Hibernate CollectionOfElements EAGER fetch duplicates elements
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