EntityResult (Java EE 5 SDK)

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Java EE 5 SDK

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摘要: REQUIRED | OPTIONAL

详细信息: ELEMENT

javax.persistence Annotation Type EntityResult

@Target(value={}) @Retention(value=RUNTIME) public @interface EntityResult

References an entity in the SELECT clause of a SQL query. If this annotation is used, the SQL statement should select all of the columns that are mapped to the entity object. This should include foreign key columns to related entities. The results obtained when insufficient data is available are undefined.

   Example
   Query q = em.createNativeQuery(
       "SELECT o.id, o.quantity, o.item, i.id, i.name, i.description "+
           "FROM Order o, Item i " +
           "WHERE (o.quantity > 25) AND (o.item = i.id)",
       "OrderItemResults");
   @SqlResultSetMapping(name="OrderItemResults",
       entities={
           @EntityResult(entityClass=com.acme.Order.class),
           @EntityResult(entityClass=com.acme.Item.class)
   })

从以下版本开始:: Java Persistence 1.0

Required Element Summary
`Class`	`entityClass` The class of the result

Optional Element Summary
`String`	`discriminatorColumn` Specifies the column name (or alias) of the column in the SELECT list that is used to determine the type of the entity instance.
`FieldResult[]`	`fields` Maps the columns specified in the SELECT list of the query to the properties or fields of the entity class.

元素详细信息

entityClass

public abstract Class entityClass

The class of the result

fields

public abstract FieldResult[] fields

Maps the columns specified in the SELECT list of the query to the properties or fields of the entity class.

默认值:: {}

discriminatorColumn

public abstract String discriminatorColumn

Specifies the column name (or alias) of the column in the SELECT list that is used to determine the type of the entity instance.

默认值:: ""

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