Client and backend. This class is shared: the same code is compiled into your app and into your server, so everything on this page works in both.

@Retention(CLASS) @Target({FIELD})

public @interface ElementCollection

Mapping for an owned collection of scalar values.

Methods

`public abstract` `FetchType fetch() default FetchType.LAZY`	Controls relationship initialization.
`public abstract` `String column() default "element_value"`	Names the scalar value column in the collection table.
`public abstract` `String positionColumn() default "element_position"`	Names the column that stores each element’s position, which keys the table together with the owner and keeps a List’s order and duplicates.

Method details

fetch

public abstract FetchType fetch() default FetchType.LAZY

Controls relationship initialization.

Returns

fetch policy; EAGER for to-one and LAZY for collections by default

column

public abstract String column() default "element_value"

Names the scalar value column in the collection table.

Returns

column name; element_value by default

positionColumn

public abstract String positionColumn() default "element_position"

Names the column that stores each element’s position, which keys the table together with the owner and keeps a List’s order and duplicates.

An empty name maps a Set to a table with no position column, keyed by the owner and the value – the layout JPA providers create, so a table one of them made can be adopted as it is. Such a Set cannot hold null, and a text value is limited to 255 characters, like any text key.

Returns

column name; element_position by default, empty for none