2.4.1. Component / Embedded

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Most often, embeddable types are used to group multiple basic type mappings and reuse them across several entities.

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<div class="title">Example 79. Simple Embeddedable</div>
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<pre class="prettyprint highlight">`@Entity
public class Person {

    @Id
    private Integer id;

    @Embedded
    private Name name;

    ...
}`</pre>
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JPA defines two terms for working with an embeddable type: `@Embeddable` and `@Embedded`.
`@Embeddable` is used to describe the mapping type itself (e.g. `Name`).
`@Embedded` is for referencing a given embeddable type (e.g. `person.name`).

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So, the embeddable type is represented by the `Name` class and the parent makes use of it through the `person.name` object composition.

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<div class="title">Example 80. Person table</div>
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<pre class="prettyprint highlight">`create table Person (
    id integer not null,
    firstName VARCHAR,
    middleName VARCHAR,
    lastName VARCHAR,
    ...
)`</pre>
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The composed values are mapped to the same table as the parent table.
Composition is part of good OO data modeling (idiomatic Java).
In fact, that table could also be mapped by the following entity type instead.

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<div class="title">Example 81. Alternative to embeddable type composition</div>
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<pre class="prettyprint highlight">`@Entity
public class Person {

    @Id
    private Integer id;

    private String firstName;

    private String middleName;

    private String lastName;

    ...
}`</pre>
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The composition form is certainly more Object-oriented, and that becomes more evident as we work with multiple embeddable types.

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