Annotation Type OrderBy
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@Target({METHOD,FIELD}) @Retention(RUNTIME) public @interface OrderBy
Specifies the ordering of the elements of a collection valued association or element collection at the point when the association or collection is retrieved.The syntax of the
value
ordering element is anorderby_list
, as follows:orderby_list::= orderby_item [,orderby_item]* orderby_item::= [property_or_field_name] [ASC | DESC]
If
ASC
orDESC
is not specified,ASC
(ascending order) is assumed.If the ordering element is not specified for an entity association, ordering by the primary key of the associated entity is assumed.
The property or field name must correspond to that of a persistent property or field of the associated class or embedded class within it. The properties or fields used in the ordering must correspond to columns for which comparison operators are supported.
The dot (".") notation is used to refer to an attribute within an embedded attribute. The value of each identifier used with the dot notation is the name of the respective embedded field or property.
The
OrderBy
annotation may be applied to an element collection. WhenOrderBy
is applied to an element collection of basic type, the ordering will be by value of the basic objects and the property or field name is not used. When specifying an ordering over an element collection of embeddable type, the dot notation must be used to specify the attribute or attributes that determine the ordering.The
OrderBy
annotation is not used when an order column is specified.Example 1: @Entity public class Course { ... @ManyToMany @OrderBy("lastname ASC") public List<Student> getStudents() {...}; ... } Example 2: @Entity public class Student { ... @ManyToMany(mappedBy="students") @OrderBy // ordering by primary key is assumed public List<Course> getCourses() {...}; ... } Example 3: @Entity public class Person { ... @ElementCollection @OrderBy("zipcode.zip, zipcode.plusFour") public Set<Address> getResidences() {...}; ... } @Embeddable public class Address { protected String street; protected String city; protected String state; @Embedded protected Zipcode zipcode; } @Embeddable public class Zipcode { protected String zip; protected String plusFour; }
- Since:
- 1.0
- See Also:
OrderColumn
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-
Optional Element Summary
Optional Elements Modifier and Type Optional Element Description java.lang.String
value
Anorderby_list
.
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-
-
Element Detail
-
value
java.lang.String value
Anorderby_list
. Specified as follows:orderby_list::= orderby_item [,orderby_item]* orderby_item::= [property_or_field_name] [ASC | DESC]
If
ASC
orDESC
is not specified,ASC
(ascending order) is assumed.If the ordering element is not specified, ordering by the primary key of the associated entity is assumed.
- Default:
- ""
-
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