JPA: defining an index column

Question

Possible Duplicate:
Specifying an index (non unique key) using JPA

Is there a way to define index on enitity column, to improve searches performance? I saw that hibernate gives @Index and @IndexColumn, but I am looking for JPA way to do it.

thanks

Here is an example of my entity, I need to index a name column

@Entity
@Table(name = "MY_TABLE")
public class MyEntity {
    private long id;
    private String name;
    private String sourceInfo;

  ...

[A list of JPA and non-JPA @Index annotations](http://stackoverflow.com/a/29650733/1429387). — naXa stands with Ukraine, Apr 15 '15 at 12:55
Jpa 2.1 is able to do this, have a look at the comment from Joel Pearson below — Marged, Feb 05 '16 at 05:01

score 30 · Accepted Answer · edited Jun 20 '20 at 09:12

30

No, jpa doesn't provide any feature to define or create indexes. For some (unknown to me) reason, it's only possible to create unique indexes in JPA.

If you are not using hibernate or if you really don't want to use those annotations, you'll need to build your annotations and processor to output or update the database accordingly, but I don't think it's very trivial (and it's definitely, non standard)

Edit

Here's an example of how to define an index with Hibernate

@org.hibernate.annotations.Table(
   appliesTo = "table_name",
   indexes = {
      @Index(name="single_column_index", columnNames = "col"),
      @Index(name="multi_column_index", columnNames = {"col1", "col2"}),
   }
)

edited Jun 20 '20 at 09:12

Community

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answered Jun 23 '11 at 12:07

Augusto

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FWIW JPA also doesn't allow the user to define Foreign-Key details; incomplete ORM specification. Only JDO allows complete control over RDBMS constraints – DataNucleus Jun 23 '11 at 12:35
Thank you, I use hibernate but wanted to avoid vendor-specific dependency. Do you have an example of hibernate solution for this problem? – lili Jun 23 '11 at 14:43
@lili, please check the edit with the example. @DataNucleus: you are so, so right, JPA is almost a joke with its basic features. – Augusto Jun 23 '11 at 16:19
5

For what it's worth, JPA 2.1 can do indexes in the @Table annotation now, see: https://blogs.oracle.com/arungupta/entry/jpa_2_1_schema_generation – Joel Pearson May 18 '14 at 04:08
See: http://stackoverflow.com/a/22658951/16206 – borjab Dec 05 '14 at 11:34

score 2 · Answer 2 · edited Feb 25 '16 at 23:07

2

There is no standard JPA annotation. (JPA does not even require DDL generation).

For EclipseLink see the @Index page.

edited Feb 25 '16 at 23:07

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answered Jun 23 '11 at 12:49

James

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score 2 · Answer 3 · edited Feb 25 '16 at 22:52

2

OpenJPA allows you to specify non-standard annotation to define index on property.

Details are here.

edited Feb 25 '16 at 22:52

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answered Dec 16 '11 at 23:12

expert

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JPA: defining an index column

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