Package org.hibernate.annotations

Annotation Interface Formula

@Target({METHOD,FIELD}) @Retention(RUNTIME) public @interface Formula
Specifies an expression written in native SQL that is used to read the value of an attribute instead of storing the value in a Column.

A Formula mapping defines a "derived" attribute, whose state is determined from other columns and functions when an entity is read from the database.

A formula may involve multiple columns and SQL operators: 

 // perform calculations using SQL operators
 @Formula("sub_total * (1.0 + tax)")
 BigDecimal totalWithTax;

It may even call SQL functions: 

 // call native SQL functions
 @Formula("upper(substring(middle_name from 0 for 1))")
 Character middleInitial;

For an entity with secondary tables, a formula may involve columns of the primary table, or columns of any one of the secondary tables. But it may not involve columns of more than one table.

The ColumnTransformer annotation is an alternative in certain cases, allowing the use of native SQL to read and write values to a column. 

 // it might be better to use @ColumnTransformer in this case
 @Formula("decrypt(credit_card_num)")
 String getCreditCardNumber() { ... }
Author:
Emmanuel Bernard, Steve Ebersole
See Also:

  • Required Element Summary

    Required Elements
    Modifier and Type
    Required Element
    Description
    String
    value
    The formula, written in native SQL.

  • Element Details

    • value

      String value
      The formula, written in native SQL.