程序包 org.hibernate.annotations

注释类型 Formula

@Target({METHOD,FIELD})
@Retention(RUNTIME)
public @interface Formula

Defines a formula (derived value) which is a SQL fragment that acts as a @Column alternative in most cases. Represents read-only state. In certain cases @ColumnTransformer might be a better option, especially as it leaves open the option of still being writable.

     // perform calculations
     @Formula( "sub_total + (sub_total * tax)" )
     long getTotalCost() { ... }
 

     // call database functions ( e.g. MySQL upper() and substring() )
     @Formula( "upper( substring( middle_name, 1 ) )" )
     Character getMiddleInitial() { ... }
 

     // this might be better handled through @ColumnTransformer
     @Formula( "decrypt(credit_card_num)" )
     String getCreditCardNumber() { ... }
 

作者:

Emmanuel Bernard, Steve Ebersole

另请参阅:

ColumnTransformer

必需元素概要

所需元素

修饰符和类型	必需的元素	说明
String	value	The formula string.

元素详细资料

value

String value

The formula string.